Return 400 for missing /api/serialize IDs (#1272)

### Summary

When two or more sibling instances share the same `Name` and
`ClassName`, Rojo's reconciler previously paired them with their
server-side counterparts purely by child order (first-unvisited match in
`GetChildren()` order). If the workspace child order ever diverged from
the server's, the wrong instance got paired so each duplicate could
inherit a sibling's properties.

This is the root of the #1257 bug: the welded parts would oscillate
between positions on each connect/disconnect because hydration kept
mis-pairing them. (#1265 stopped the sync fallback from scrambling child
order in the first place but this PR makes hydration robust even when
order *does* diverge.)

This PR makes `hydrate` break ties by comparing properties: when several
existing children match on `Name`+`ClassName`, it scores each candidate
by how many of the virtual instance's properties match the candidate's
live values, and picks the best. Order remains the tiebreak when scores
are equal, so behavior is unchanged for uniquely-named instances and for
indistinguishable siblings.

### Changes

- `trueEquals.lua`: extracted verbatim from `diff.lua` (the fuzzy
value-equality helper) so it can be shared. No behavior change;
`diff.lua` now requires it.
- `countMatchingProperties.lua`: added
`countMatchingProperties(instance, virtualInstance, instanceMap) ->
number`. Skips `Ref` properties (the instanceMap isn't fully built
mid-hydrate, so refs can't be decoded reliably, and they're a poor
disambiguator anyway) and any property that can't be read or decoded.
- `hydrate.lua`: See details below.

### Hydrate Changes

This touches `hydrate`, which runs over the whole tree on every
connect/resync, so I want state clearly that **the common path is faster
than before, not slower** even for parents with thousands of children!

The old algorithm was a nested scan: for each of `V` virtual children,
scan existing children until the first unvisited `Name`+`ClassName`
match. Two costs stand out:
- A `pcall` (to guard DataModel permission errors) ran on every
comparison (up to `V*E` `pcall`s per parent).
- Even for in-order trees the re-scanning of the visited prefix made it
`O(V^2)`.

The new algorithm does a single bucketing pass, then `O(1)` lookups:
1. One `O(E)` pass groups existing children into nested
`buckets[name][className]` tables. This runs exactly `E` `pcall`s total
(one per child), down from the `V*E` worst case.
2. Each virtual child does an `O(1)` bucket lookup to find its
candidates.
3. A per-bucket cursor skips already-paired children, so order-based
matching is amortized `O(1)` per child instead of rescanning.

| Scenario | Old | New |
| ------------------------------------------------ |
--------------------------------------- |
--------------------------------------------- |
| Unique-named children (typical, incl. thousands) | `O(V^2)`, plus up
to `V*E` pcalls | `O(V + E)`, plus exactly `E` pcalls |
| `C <= 32` candidates | `O(C^2)` | `O(P * C^2)` scoring |
| `C > 32` candidates | `O(C^2)` | `O(C)` |

Property scoring (`getProperty`/`decodeValue`/`trueEquals`) is the only
new expense, and it's gated two ways:
- It runs only when a `Name`+`ClassName` group has >=2 candidates (i.e.
never for uniquely-named instances).
- A cap, `MAX_CANDIDATES_TO_SCORE = 32`, means scoring only kicks in
once a group has <=32 unvisited candidates. A folder of thousands of
identically-named parts therefore does not trigger scoring; it falls
back to the original order-based pairing. The worst-case added scoring
work is bounded to roughly `32^2` property comparisons per group,
independent of group size.

So overall this is faster when you have unique names or many children.
It is slower but more robust when you have small groups of duplicate
names. Memory usage is increased as it creates the candidate buckets.

.github/workflows/ci.yml

@@ -60,7 +60,7 @@ jobs:
         submodules: true
 
     - name: Install Rust
-      uses: dtolnay/rust-toolchain@1.79.0
+      uses: dtolnay/rust-toolchain@1.88.0
 
     - name: Restore Rust Cache
       uses: actions/cache/restore@v4

.github/workflows/release.yml

@@ -45,6 +45,13 @@ jobs:
           name: Rojo.rbxm
           path: Rojo.rbxm
       
+      - name: Upload Plugin to Roblox
+        env:
+          RBX_API_KEY: ${{ secrets.PLUGIN_UPLOAD_TOKEN }}
+          RBX_UNIVERSE_ID: ${{ vars.PLUGIN_CI_PLACE_ID }}
+          RBX_PLACE_ID: ${{ vars.PLUGIN_CI_UNIVERSE_ID }}
+        run: lune run upload-plugin Rojo.rbxm
+
   build:
     needs: ["create-release"]
     strategy:

.gitignore

@@ -23,3 +23,6 @@
 # Macos file system junk
 ._*
 .DS_STORE
+
+# JetBrains IDEs
+/.idea/

.gitmodules

@@ -16,3 +16,9 @@
 [submodule "plugin/Packages/Highlighter"]
 	path = plugin/Packages/Highlighter
 	url = https://github.com/boatbomber/highlighter.git
+[submodule "plugin/Packages/msgpack-luau"]
+	path = plugin/Packages/msgpack-luau
+	url = https://github.com/cipharius/msgpack-luau/
+[submodule ".lune/opencloud-execute"]
+	path = .lune/opencloud-execute
+	url = https://github.com/Dekkonot/opencloud-luau-execute-lune.git

.lune/.config.luau

@@ -0,0 +1,8 @@
+return {
+	luau = {
+		languagemode = "strict",
+		aliases = {
+			lune = "~/.lune/.typedefs/0.10.4/",
+		},
+	},
+}

.lune/scripts/plugin-upload.luau

@@ -0,0 +1,51 @@
+local args: any = ...
+assert(args, "no arguments passed to script")
+
+local input: buffer = args.BinaryInput
+
+local AssetService = game:GetService("AssetService")
+local SerializationService = game:GetService("SerializationService")
+local EncodingService = game:GetService("EncodingService")
+
+local input_hash: buffer = EncodingService:ComputeBufferHash(input, Enum.HashAlgorithm.Sha256)
+local hex_hash: { string } = table.create(buffer.len(input_hash))
+for i = 0, buffer.len(input_hash) - 1 do
+	table.insert(hex_hash, string.format("%02x", buffer.readu8(input_hash, i)))
+end
+
+print(`Deserializing plugin file (size: {buffer.len(input)} bytes, hash: {table.concat(hex_hash, "")})`)
+local plugin = SerializationService:DeserializeInstancesAsync(input)[1]
+
+local UploadDetails = require(plugin.UploadDetails) :: any
+local PLUGIN_ID = UploadDetails.assetId
+local PLUGIN_NAME = UploadDetails.name
+local PLUGIN_DESCRIPTION = UploadDetails.description
+local PLUGIN_CREATOR_ID = UploadDetails.creatorId
+local PLUGIN_CREATOR_TYPE = UploadDetails.creatorType
+
+assert(typeof(PLUGIN_ID) == "number", "UploadDetails did not contain a number field 'assetId'")
+assert(typeof(PLUGIN_NAME) == "string", "UploadDetails did not contain a string field 'name'")
+assert(typeof(PLUGIN_DESCRIPTION) == "string", "UploadDetails did not contain a string field 'description'")
+assert(typeof(PLUGIN_CREATOR_ID) == "number", "UploadDetails did not contain a number field 'creatorId'")
+assert(typeof(PLUGIN_CREATOR_TYPE) == "string", "UploadDetails did not contain a string field 'creatorType'")
+assert(
+	Enum.AssetCreatorType:FromName(PLUGIN_CREATOR_TYPE) ~= nil,
+	"UploadDetails field 'creatorType' was not a valid member of Enum.AssetCreatorType"
+)
+
+print(`Uploading to {PLUGIN_ID}`)
+print(`Plugin Name: {PLUGIN_NAME}`)
+print(`Plugin Description: {PLUGIN_DESCRIPTION}`)
+
+local result, version_or_err = AssetService:CreateAssetVersionAsync(plugin, Enum.AssetType.Plugin, PLUGIN_ID, {
+	["Name"] = PLUGIN_NAME,
+	["Description"] = PLUGIN_DESCRIPTION,
+	["CreatorId"] = PLUGIN_CREATOR_ID,
+	["CreatorType"] = Enum.AssetCreatorType:FromName(PLUGIN_CREATOR_TYPE),
+})
+
+if result ~= Enum.CreateAssetResult.Success then
+	error(`Plugin failed to upload because: {result.Name} - {version_or_err}`)
+end
+
+print(`Plugin uploaded successfully. New version is {version_or_err}.`)

.lune/upload-plugin.luau

@@ -0,0 +1,78 @@
+local fs = require("@lune/fs")
+local process = require("@lune/process")
+local stdio = require("@lune/stdio")
+
+local luau_execute = require("./opencloud-execute")
+
+local UNIVERSE_ID = process.env["RBX_UNIVERSE_ID"]
+local PLACE_ID = process.env["RBX_PLACE_ID"]
+
+local version_string = fs.readFile("plugin/Version.txt")
+local versions = { string.match(version_string, "^v?(%d+)%.(%d+)%.(%d+)(.*)$") }
+if versions[4] ~= "" then
+	print("This release is a pre-release. Skipping uploading plugin.")
+	process.exit(0)
+end
+
+local plugin_path = process.args[1]
+assert(
+	typeof(plugin_path) == "string",
+	"no plugin path provided, expected usage is `lune run upload-plugin [PATH TO RBXM]`."
+)
+
+-- For local testing
+if process.env["CI"] ~= "true" then
+	local rojo = process.exec("rojo", { "build", "plugin.project.json", "--output", plugin_path })
+	if not rojo.ok then
+		stdio.ewrite("plugin upload failed because: could not build plugin.rbxm\n\n")
+		stdio.ewrite(rojo.stderr)
+		stdio.ewrite("\n")
+		process.exit(1)
+	end
+else
+	assert(fs.isFile(plugin_path), `Plugin file did not exist at {plugin_path}`)
+end
+local plugin_content = fs.readFile(plugin_path)
+
+local engine_script = fs.readFile(".lune/scripts/plugin-upload.luau")
+
+print("Creating task to upload plugin")
+local task = luau_execute.create_task_latest(UNIVERSE_ID, PLACE_ID, engine_script, 300, false, plugin_content)
+
+print("Waiting for task to finish")
+local success = luau_execute.await_finish(task)
+if not success then
+	local error = luau_execute.get_error(task)
+	assert(error, "could not fetch error from task")
+	stdio.ewrite("plugin upload failed because: task did not finish successfully\n\n")
+	stdio.ewrite(error.code)
+	stdio.ewrite("\n")
+	stdio.ewrite(error.message)
+	stdio.ewrite("\n")
+	process.exit(1)
+end
+
+print("Output from task:\n")
+for _, log in luau_execute.get_structured_logs(task) do
+	if log.messageType == "ERROR" then
+		stdio.write(stdio.color("red"))
+		stdio.write(log.message)
+		stdio.write("\n")
+		stdio.write(stdio.color("reset"))
+	elseif log.messageType == "INFO" then
+		stdio.write(stdio.color("cyan"))
+		stdio.write(log.message)
+		stdio.write("\n")
+		stdio.write(stdio.color("reset"))
+	elseif log.messageType == "WARNING" then
+		stdio.write(stdio.color("yellow"))
+		stdio.write(log.message)
+		stdio.write("\n")
+		stdio.write(stdio.color("reset"))
+	else
+		stdio.write(stdio.color("reset"))
+		stdio.write(log.message)
+		stdio.write("\n")
+		stdio.write(stdio.color("reset"))
+	end
+end

CONTRIBUTING.md

@@ -13,11 +13,27 @@ Code contributions are welcome for features and bugs that have been reported in
 
 You'll want these tools to work on Rojo:
 
-* Latest stable Rust compiler
-* Latest stable [Rojo](https://github.com/rojo-rbx/rojo)
+* Rust 1.88 or newer
+  * Rustfmt and Clippy are used for code formatting and linting.
 * [Rokit](https://github.com/rojo-rbx/rokit)
 * [Luau Language Server](https://github.com/JohnnyMorganz/luau-lsp) (Only needed if working on the Studio plugin.)
 
+Rokit installs the pinned Rojo, Selene, StyLua, Lune, and run-in-roblox versions listed in [`rokit.toml`](rokit.toml):
+
+```bash
+rokit install
+```
+
+Before opening a pull request, run the relevant checks:
+
+```bash
+cargo test
+cargo fmt -- --check
+cargo clippy
+stylua --check plugin/src
+selene plugin/src
+```
+
 When working on the Studio plugin, we recommend using this command to automatically rebuild the plugin when you save a change:
 
 *(Make sure you've enabled the Studio setting to reload plugins on file change!)*
@@ -28,7 +44,7 @@ bash scripts/watch-build-plugin.sh
 
 You can also run the plugin's unit tests with the following:
 
-*(Make sure you have `run-in-roblox` installed first!)*
+*(If you are not using Rokit, make sure you have `run-in-roblox` installed first!)*
 
 ```bash
 bash scripts/unit-test-plugin.sh
@@ -48,26 +64,26 @@ Please file issues and we'll try to help figure out what the best way forward is
 
 ## Local Development Gotchas
 
-If your build fails with "Error: failed to open file `D:\code\rojo\plugin\modules\roact\src`" you need to update your Git submodules.
+If your build fails with an error about a missing path under `plugin/Packages`, such as `plugin/Packages/Roact`, you need to update your Git submodules.
 Run the command and try building again: `git submodule update --init --recursive`.
 
 ## Pushing a Rojo Release
-The Rojo release process is pretty manual right now. If you need to do it, here's how:
+The Rojo release process is driven by the GitHub Actions release workflow. If you need to do it, here's how:
 
 1. Bump server version in [`Cargo.toml`](Cargo.toml)
-2. Bump plugin version in [`plugin/src/Config.lua`](plugin/src/Config.lua)
-3. Run `cargo test` to update `Cargo.lock` and run tests
+2. Bump plugin version in [`plugin/Version.txt`](plugin/Version.txt)
+   * The build checks that the Cargo and plugin versions match.
+3. Run `cargo test` to update `Cargo.lock` after the version bump and run tests
 4. Update [`CHANGELOG.md`](CHANGELOG.md)
 5. Commit!
     * `git add . && git commit -m "Release vX.Y.Z"`
 6. Tag the commit
     * `git tag vX.Y.Z`
-7. Publish the CLI
-    * `cargo publish`
-8. Publish the Plugin
-    * `cargo run -- upload plugin --asset_id 6415005344`
-9. Push commits and tags
+7. Push commits and tags
     * `git push && git push --tags`
+8. Wait for the GitHub Actions release workflow to create the draft release and upload CLI/plugin artifacts
+9. Publish the CLI crate
+    * `cargo publish`
 10. Copy GitHub release content from previous release
     * Update the leading text with a summary about the release
     * Paste the changelog notes (as-is!) from [`CHANGELOG.md`](CHANGELOG.md)

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "rojo"
-version = "7.5.1"
-rust-version = "1.79.0"
+version = "7.7.0-rc.1"
+rust-version = "1.88"
 authors = [
     "Lucien Greathouse <me@lpghatguy.com>",
     "Micah Reid <git@dekkonot.com>",
@@ -46,20 +46,22 @@ name = "build"
 harness = false
 
 [dependencies]
-memofs = { version = "0.3.0", path = "crates/memofs" }
+memofs = { version = "0.3.1", path = "crates/memofs" }
 
 # These dependencies can be uncommented when working on rbx-dom simultaneously
-# rbx_binary = { path = "../rbx-dom/rbx_binary" }
+# rbx_binary = { path = "../rbx-dom/rbx_binary", features = [
+#     "unstable_text_format",
+# ] }
 # rbx_dom_weak = { path = "../rbx-dom/rbx_dom_weak" }
 # rbx_reflection = { path = "../rbx-dom/rbx_reflection" }
 # rbx_reflection_database = { path = "../rbx-dom/rbx_reflection_database" }
 # rbx_xml = { path = "../rbx-dom/rbx_xml" }
 
-rbx_binary = "1.0.0"
-rbx_dom_weak = "3.0.0"
-rbx_reflection = "5.0.0"
-rbx_reflection_database = "1.0.3"
-rbx_xml = "1.0.0"
+rbx_binary = { version = "2.0.1", features = ["unstable_text_format"] }
+rbx_dom_weak = "4.1.0"
+rbx_reflection = "6.1.0"
+rbx_reflection_database = "2.0.2"
+rbx_xml = "2.0.1"
 
 anyhow = "1.0.80"
 backtrace = "0.3.69"
@@ -72,6 +74,7 @@ futures = "0.3.30"
 globset = "0.4.14"
 humantime = "2.1.0"
 hyper = { version = "0.14.28", features = ["server", "tcp", "http1"] }
+hyper-tungstenite = "0.11.0"
 jod-thread = "0.1.2"
 log = "0.4.21"
 num_cpus = "1.16.0"
@@ -85,16 +88,25 @@ reqwest = { version = "0.11.24", default-features = false, features = [
 ritz = "0.1.0"
 roblox_install = "1.0.0"
 serde = { version = "1.0.197", features = ["derive", "rc"] }
-serde_json = "1.0.114"
+serde_json = "1.0.145"
+jsonc-parser = { version = "0.27.0", features = ["serde"] }
+strum = { version = "0.27", features = ["derive"] }
 toml = "0.5.11"
 termcolor = "1.4.1"
 thiserror = "1.0.57"
-tokio = { version = "1.36.0", features = ["rt", "rt-multi-thread"] }
+tokio = { version = "1.36.0", features = ["rt", "rt-multi-thread", "macros"] }
 uuid = { version = "1.7.0", features = ["v4", "serde"] }
 clap = { version = "3.2.25", features = ["derive"] }
 profiling = "1.0.15"
 yaml-rust2 = "0.10.3"
 data-encoding = "2.8.0"
+pathdiff = "0.2.3"
+
+blake3 = "1.5.0"
+float-cmp = "0.9.0"
+indexmap = { version = "2.10.0", features = ["serde"] }
+rmp-serde = "1.3.0"
+serde_bytes = "0.11.19"
 
 [target.'cfg(windows)'.dependencies]
 winreg = "0.10.1"
@@ -113,7 +125,7 @@ semver = "1.0.22"
 rojo-insta-ext = { path = "crates/rojo-insta-ext" }
 
 criterion = "0.3.6"
-insta = { version = "1.36.1", features = ["redactions", "yaml"] }
+insta = { version = "1.36.1", features = ["redactions", "yaml", "json"] }
 paste = "1.0.14"
 pretty_assertions = "1.4.0"
 serde_yaml = "0.8.26"

README.md

@@ -25,12 +25,11 @@ Rojo enables:
 * Versioning your game, library, or plugin using Git or another VCS
 * Streaming `rbxmx` and `rbxm` models into your game in real time
 * Packaging and deploying your project to Roblox.com from the command line
+* Pulling Instances from Roblox place and model files back into an existing Rojo project with `rojo syncback`
 
-In the future, Rojo will be able to:
+Rojo also has an optional two-way sync setting in the Studio plugin for syncing supported Studio edits back to the filesystem.
 
-* Sync instances from Roblox Studio to the filesystem
-* Automatically convert your existing game to work with Rojo
-* Import custom instances like MoonScript code
+Some workflows, like fully automatic conversion of every existing game into a Rojo project, are still limited and may require manual project configuration.
 
 ## [Documentation](https://rojo.space/docs)
 Documentation is hosted in the [rojo.space repository](https://github.com/rojo-rbx/rojo.space).
@@ -40,7 +39,7 @@ Check out our [contribution guide](CONTRIBUTING.md) for detailed instructions fo
 
 Pull requests are welcome!
 
-Rojo supports Rust 1.70.0 and newer. The minimum supported version of Rust is based on the latest versions of the dependencies that Rojo has.
+Rojo supports Rust 1.88 and newer. The minimum supported version of Rust is based on the latest versions of the dependencies that Rojo has.
 
 ## License
 Rojo is available under the terms of the Mozilla Public License, Version 2.0. See [LICENSE.txt](LICENSE.txt) for details.

assets/project-templates/model/gitignore.txt

@@ -1,3 +1,5 @@
 # Roblox Studio lock files
 /*.rbxlx.lock
 /*.rbxl.lock
+
+sourcemap.json

assets/project-templates/place/gitignore.txt

@@ -4,3 +4,5 @@
 # Roblox Studio lock files
 /*.rbxlx.lock
 /*.rbxl.lock
+
+sourcemap.json

assets/project-templates/place/src/client/init.client.luau

@@ -0,0 +1 @@
+print("Hello world, from client!")

assets/project-templates/place/src/server/init.server.luau

@@ -0,0 +1 @@
+print("Hello world, from server!")

assets/project-templates/place/src/shared/Hello.luau

@@ -0,0 +1,3 @@
+return function()
+	print("Hello, world!")
+end

assets/project-templates/plugin/gitignore.txt

@@ -1,3 +1,5 @@
 # Plugin model files
 /{project_name}.rbxmx
 /{project_name}.rbxm
+
+sourcemap.json

assets/project-templates/plugin/src/init.server.luau

@@ -0,0 +1 @@
+print("Hello world, from plugin!")

build.rs

@@ -30,6 +30,11 @@ fn snapshot_from_fs_path(path: &Path) -> io::Result<VfsSnapshot> {
                 continue;
             }
 
+            // Ignore images in msgpack-luau because they aren't UTF-8 encoded.
+            if file_name.ends_with(".png") {
+                continue;
+            }
+
             let child_snapshot = snapshot_from_fs_path(&entry.path())?;
             children.push((file_name, child_snapshot));
         }
@@ -47,6 +52,7 @@ fn main() -> Result<(), anyhow::Error> {
 
     let root_dir = PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap());
     let plugin_dir = root_dir.join("plugin");
+    let templates_dir = root_dir.join("assets").join("project-templates");
 
     let our_version = Version::parse(env::var_os("CARGO_PKG_VERSION").unwrap().to_str().unwrap())?;
     let plugin_version =
@@ -57,7 +63,9 @@ fn main() -> Result<(), anyhow::Error> {
         "plugin version does not match Cargo version"
     );
 
-    let snapshot = VfsSnapshot::dir(hashmap! {
+    let template_snapshot = snapshot_from_fs_path(&templates_dir)?;
+
+    let plugin_snapshot = VfsSnapshot::dir(hashmap! {
         "default.project.json" => snapshot_from_fs_path(&root_dir.join("plugin.project.json"))?,
         "plugin" => VfsSnapshot::dir(hashmap! {
             "fmt" => snapshot_from_fs_path(&plugin_dir.join("fmt"))?,
@@ -67,13 +75,15 @@ fn main() -> Result<(), anyhow::Error> {
             "src" => snapshot_from_fs_path(&plugin_dir.join("src"))?,
             "Packages" => snapshot_from_fs_path(&plugin_dir.join("Packages"))?,
             "Version.txt" => snapshot_from_fs_path(&plugin_dir.join("Version.txt"))?,
+            "UploadDetails.json" => snapshot_from_fs_path(&plugin_dir.join("UploadDetails.json"))?,
         }),
     });
 
-    let out_path = Path::new(&out_dir).join("plugin.bincode");
-    let out_file = File::create(out_path)?;
+    let template_file = File::create(Path::new(&out_dir).join("templates.bincode"))?;
+    let plugin_file = File::create(Path::new(&out_dir).join("plugin.bincode"))?;
 
-    bincode::serialize_into(out_file, &snapshot)?;
+    bincode::serialize_into(plugin_file, &plugin_snapshot)?;
+    bincode::serialize_into(template_file, &template_snapshot)?;
 
     println!("cargo:rerun-if-changed=build/windows/rojo-manifest.rc");
     println!("cargo:rerun-if-changed=build/windows/rojo.manifest");

crates/memofs/CHANGELOG.md

@@ -1,6 +1,17 @@
 # memofs Changelog
 
 ## Unreleased Changes
+* Added `Vfs::canonicalize`. [#1201]
+* **Breaking:** `StdBackend::new` and `Vfs::new_default` now return `io::Result`, so a failure to create the filesystem watcher is reported as an error instead of panicking. The `Default` implementation for `StdBackend` has been removed as a result. [#1267]
+
+[#1267]: https://github.com/rojo-rbx/rojo/pull/1267
+
+## 0.3.1 (2025-11-27)
+* Added `Vfs::exists`. [#1169]
+* Added `create_dir` and `create_dir_all` to allow creating directories. [#937]
+
+[#1169]: https://github.com/rojo-rbx/rojo/pull/1169
+[#937]: https://github.com/rojo-rbx/rojo/pull/937
 
 ## 0.3.0 (2024-03-15)
 * Changed `StdBackend` file watching component to use minimal recursive watches. [#830]

crates/memofs/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "memofs"
 description = "Virtual filesystem with configurable backends."
-version = "0.3.0"
+version = "0.3.1"
 authors = [
     "Lucien Greathouse <me@lpghatguy.com>",
     "Micah Reid <git@dekkonot.com>",
@@ -19,3 +19,6 @@ crossbeam-channel = "0.5.12"
 fs-err = "2.11.0"
 notify = "4.0.17"
 serde = { version = "1.0.197", features = ["derive"] }
+
+[dev-dependencies]
+tempfile = "3.10.1"

crates/memofs/src/in_memory_fs.rs

@@ -157,6 +157,11 @@ impl VfsBackend for InMemoryFs {
         )
     }
 
+    fn exists(&mut self, path: &Path) -> io::Result<bool> {
+        let inner = self.inner.lock().unwrap();
+        Ok(inner.entries.contains_key(path))
+    }
+
     fn read_dir(&mut self, path: &Path) -> io::Result<ReadDir> {
         let inner = self.inner.lock().unwrap();
 
@@ -176,6 +181,21 @@ impl VfsBackend for InMemoryFs {
         }
     }
 
+    fn create_dir(&mut self, path: &Path) -> io::Result<()> {
+        let mut inner = self.inner.lock().unwrap();
+        inner.load_snapshot(path.to_path_buf(), VfsSnapshot::empty_dir())
+    }
+
+    fn create_dir_all(&mut self, path: &Path) -> io::Result<()> {
+        let mut inner = self.inner.lock().unwrap();
+        let mut path_buf = path.to_path_buf();
+        while let Some(parent) = path_buf.parent() {
+            inner.load_snapshot(parent.to_path_buf(), VfsSnapshot::empty_dir())?;
+            path_buf.pop();
+        }
+        inner.load_snapshot(path.to_path_buf(), VfsSnapshot::empty_dir())
+    }
+
     fn remove_file(&mut self, path: &Path) -> io::Result<()> {
         let mut inner = self.inner.lock().unwrap();
 
@@ -212,6 +232,33 @@ impl VfsBackend for InMemoryFs {
         }
     }
 
+    // TODO: We rely on Rojo to prepend cwd to any relative path before storing paths
+    // in MemoFS. The current implementation will error if no prepended absolute path
+    // is found. It really only normalizes paths within the provided path's context.
+    // Example: "/Users/username/project/../other/file.txt" ->
+    // "/Users/username/other/file.txt"
+    // Erroneous example: "/Users/../../other/file.txt" -> "/other/file.txt"
+    // This is not very robust. We should implement proper path normalization here or otherwise
+    // warn if we are missing context and can not fully canonicalize the path correctly.
+    fn canonicalize(&mut self, path: &Path) -> io::Result<PathBuf> {
+        let mut normalized = PathBuf::new();
+        for component in path.components() {
+            match component {
+                std::path::Component::ParentDir => {
+                    normalized.pop();
+                }
+                std::path::Component::CurDir => {}
+                _ => normalized.push(component),
+            }
+        }
+
+        let inner = self.inner.lock().unwrap();
+        match inner.entries.get(&normalized) {
+            Some(_) => Ok(normalized),
+            None => not_found(&normalized),
+        }
+    }
+
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
         let inner = self.inner.lock().unwrap();
 
@@ -228,23 +275,17 @@ impl VfsBackend for InMemoryFs {
 }
 
 fn must_be_file<T>(path: &Path) -> io::Result<T> {
-    Err(io::Error::new(
-        io::ErrorKind::Other,
-        format!(
+    Err(io::Error::other(format!(
         "path {} was a directory, but must be a file",
         path.display()
-        ),
-    ))
+    )))
 }
 
 fn must_be_dir<T>(path: &Path) -> io::Result<T> {
-    Err(io::Error::new(
-        io::ErrorKind::Other,
-        format!(
+    Err(io::Error::other(format!(
         "path {} was a file, but must be a directory",
         path.display()
-        ),
-    ))
+    )))
 }
 
 fn not_found<T>(path: &Path) -> io::Result<T> {

crates/memofs/src/lib.rs

@@ -70,10 +70,14 @@ impl<T> IoResultExt<T> for io::Result<T> {
 pub trait VfsBackend: sealed::Sealed + Send + 'static {
     fn read(&mut self, path: &Path) -> io::Result<Vec<u8>>;
     fn write(&mut self, path: &Path, data: &[u8]) -> io::Result<()>;
+    fn exists(&mut self, path: &Path) -> io::Result<bool>;
     fn read_dir(&mut self, path: &Path) -> io::Result<ReadDir>;
+    fn create_dir(&mut self, path: &Path) -> io::Result<()>;
+    fn create_dir_all(&mut self, path: &Path) -> io::Result<()>;
     fn metadata(&mut self, path: &Path) -> io::Result<Metadata>;
     fn remove_file(&mut self, path: &Path) -> io::Result<()>;
     fn remove_dir_all(&mut self, path: &Path) -> io::Result<()>;
+    fn canonicalize(&mut self, path: &Path) -> io::Result<PathBuf>;
 
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent>;
     fn watch(&mut self, path: &Path) -> io::Result<()>;
@@ -173,6 +177,11 @@ impl VfsInner {
         Ok(Arc::new(contents_str.into()))
     }
 
+    fn exists<P: AsRef<Path>>(&mut self, path: P) -> io::Result<bool> {
+        let path = path.as_ref();
+        self.backend.exists(path)
+    }
+
     fn write<P: AsRef<Path>, C: AsRef<[u8]>>(&mut self, path: P, contents: C) -> io::Result<()> {
         let path = path.as_ref();
         let contents = contents.as_ref();
@@ -190,6 +199,16 @@ impl VfsInner {
         Ok(dir)
     }
 
+    fn create_dir<P: AsRef<Path>>(&mut self, path: P) -> io::Result<()> {
+        let path = path.as_ref();
+        self.backend.create_dir(path)
+    }
+
+    fn create_dir_all<P: AsRef<Path>>(&mut self, path: P) -> io::Result<()> {
+        let path = path.as_ref();
+        self.backend.create_dir_all(path)
+    }
+
     fn remove_file<P: AsRef<Path>>(&mut self, path: P) -> io::Result<()> {
         let path = path.as_ref();
         let _ = self.backend.unwatch(path);
@@ -207,6 +226,11 @@ impl VfsInner {
         self.backend.metadata(path)
     }
 
+    fn canonicalize<P: AsRef<Path>>(&mut self, path: P) -> io::Result<PathBuf> {
+        let path = path.as_ref();
+        self.backend.canonicalize(path)
+    }
+
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
         self.backend.event_receiver()
     }
@@ -231,8 +255,11 @@ pub struct Vfs {
 
 impl Vfs {
     /// Creates a new `Vfs` with the default backend, `StdBackend`.
-    pub fn new_default() -> Self {
-        Self::new(StdBackend::new())
+    ///
+    /// Returns an error if the filesystem watcher could not be initialized,
+    /// which can happen in restricted or sandboxed environments.
+    pub fn new_default() -> io::Result<Self> {
+        Ok(Self::new(StdBackend::new()?))
     }
 
     /// Creates a new `Vfs` with the given backend.
@@ -326,6 +353,42 @@ impl Vfs {
         self.inner.lock().unwrap().read_dir(path)
     }
 
+    /// Return whether the given path exists.
+    ///
+    /// Roughly equivalent to [`std::fs::exists`][std::fs::exists].
+    ///
+    /// [std::fs::exists]: https://doc.rust-lang.org/stable/std/fs/fn.exists.html
+    #[inline]
+    pub fn exists<P: AsRef<Path>>(&self, path: P) -> io::Result<bool> {
+        let path = path.as_ref();
+        self.inner.lock().unwrap().exists(path)
+    }
+
+    /// Creates a directory at the provided location.
+    ///
+    /// Roughly equivalent to [`std::fs::create_dir`][std::fs::create_dir].
+    /// Similiar to that function, this function will fail if the parent of the
+    /// path does not exist.
+    ///
+    /// [std::fs::create_dir]: https://doc.rust-lang.org/stable/std/fs/fn.create_dir.html
+    #[inline]
+    pub fn create_dir<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
+        let path = path.as_ref();
+        self.inner.lock().unwrap().create_dir(path)
+    }
+
+    /// Creates a directory at the provided location, recursively creating
+    /// all parent components if they are missing.
+    ///
+    /// Roughly equivalent to [`std::fs::create_dir_all`][std::fs::create_dir_all].
+    ///
+    /// [std::fs::create_dir_all]: https://doc.rust-lang.org/stable/std/fs/fn.create_dir_all.html
+    #[inline]
+    pub fn create_dir_all<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
+        let path = path.as_ref();
+        self.inner.lock().unwrap().create_dir_all(path)
+    }
+
     /// Remove a file.
     ///
     /// Roughly equivalent to [`std::fs::remove_file`][std::fs::remove_file].
@@ -359,6 +422,19 @@ impl Vfs {
         self.inner.lock().unwrap().metadata(path)
     }
 
+    /// Normalize a path via the underlying backend.
+    ///
+    /// Roughly equivalent to [`std::fs::canonicalize`][std::fs::canonicalize]. Relative paths are
+    /// resolved against the backend's current working directory (if applicable) and errors are
+    /// surfaced directly from the backend.
+    ///
+    /// [std::fs::canonicalize]: https://doc.rust-lang.org/stable/std/fs/fn.canonicalize.html
+    #[inline]
+    pub fn canonicalize<P: AsRef<Path>>(&self, path: P) -> io::Result<PathBuf> {
+        let path = path.as_ref();
+        self.inner.lock().unwrap().canonicalize(path)
+    }
+
     /// Retrieve a handle to the event receiver for this `Vfs`.
     #[inline]
     pub fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
@@ -428,6 +504,31 @@ impl VfsLock<'_> {
         self.inner.read_dir(path)
     }
 
+    /// Creates a directory at the provided location.
+    ///
+    /// Roughly equivalent to [`std::fs::create_dir`][std::fs::create_dir].
+    /// Similiar to that function, this function will fail if the parent of the
+    /// path does not exist.
+    ///
+    /// [std::fs::create_dir]: https://doc.rust-lang.org/stable/std/fs/fn.create_dir.html
+    #[inline]
+    pub fn create_dir<P: AsRef<Path>>(&mut self, path: P) -> io::Result<()> {
+        let path = path.as_ref();
+        self.inner.create_dir(path)
+    }
+
+    /// Creates a directory at the provided location, recursively creating
+    /// all parent components if they are missing.
+    ///
+    /// Roughly equivalent to [`std::fs::create_dir_all`][std::fs::create_dir_all].
+    ///
+    /// [std::fs::create_dir_all]: https://doc.rust-lang.org/stable/std/fs/fn.create_dir_all.html
+    #[inline]
+    pub fn create_dir_all<P: AsRef<Path>>(&mut self, path: P) -> io::Result<()> {
+        let path = path.as_ref();
+        self.inner.create_dir_all(path)
+    }
+
     /// Remove a file.
     ///
     /// Roughly equivalent to [`std::fs::remove_file`][std::fs::remove_file].
@@ -461,6 +562,13 @@ impl VfsLock<'_> {
         self.inner.metadata(path)
     }
 
+    /// Normalize a path via the underlying backend.
+    #[inline]
+    pub fn normalize<P: AsRef<Path>>(&mut self, path: P) -> io::Result<PathBuf> {
+        let path = path.as_ref();
+        self.inner.canonicalize(path)
+    }
+
     /// Retrieve a handle to the event receiver for this `Vfs`.
     #[inline]
     pub fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
@@ -476,7 +584,9 @@ impl VfsLock<'_> {
 
 #[cfg(test)]
 mod test {
-    use crate::{InMemoryFs, Vfs, VfsSnapshot};
+    use crate::{InMemoryFs, StdBackend, Vfs, VfsSnapshot};
+    use std::io;
+    use std::path::PathBuf;
 
     /// https://github.com/rojo-rbx/rojo/issues/899
     #[test]
@@ -492,4 +602,62 @@ mod test {
             "bar\nfoo\n\n"
         );
     }
+
+    /// https://github.com/rojo-rbx/rojo/issues/1200
+    #[test]
+    fn canonicalize_in_memory_success() {
+        let mut imfs = InMemoryFs::new();
+        let contents = "Lorem ipsum dolor sit amet.".to_string();
+
+        imfs.load_snapshot("/test/file.txt", VfsSnapshot::file(contents.to_string()))
+            .unwrap();
+
+        let vfs = Vfs::new(imfs);
+
+        assert_eq!(
+            vfs.canonicalize("/test/nested/../file.txt").unwrap(),
+            PathBuf::from("/test/file.txt")
+        );
+        assert_eq!(
+            vfs.read_to_string(vfs.canonicalize("/test/nested/../file.txt").unwrap())
+                .unwrap()
+                .to_string(),
+            contents.to_string()
+        );
+    }
+
+    #[test]
+    fn canonicalize_in_memory_missing_errors() {
+        let imfs = InMemoryFs::new();
+        let vfs = Vfs::new(imfs);
+
+        let err = vfs.canonicalize("test").unwrap_err();
+        assert_eq!(err.kind(), io::ErrorKind::NotFound);
+    }
+
+    #[test]
+    fn canonicalize_std_backend_success() {
+        let contents = "Lorem ipsum dolor sit amet.".to_string();
+        let dir = tempfile::tempdir().unwrap();
+        let file_path = dir.path().join("file.txt");
+        fs_err::write(&file_path, contents.to_string()).unwrap();
+
+        let vfs = Vfs::new(StdBackend::new().unwrap());
+        let canonicalized = vfs.canonicalize(&file_path).unwrap();
+        assert_eq!(canonicalized, file_path.canonicalize().unwrap());
+        assert_eq!(
+            vfs.read_to_string(&canonicalized).unwrap().to_string(),
+            contents.to_string()
+        );
+    }
+
+    #[test]
+    fn canonicalize_std_backend_missing_errors() {
+        let dir = tempfile::tempdir().unwrap();
+        let file_path = dir.path().join("test");
+
+        let vfs = Vfs::new(StdBackend::new().unwrap());
+        let err = vfs.canonicalize(&file_path).unwrap_err();
+        assert_eq!(err.kind(), io::ErrorKind::NotFound);
+    }
 }

crates/memofs/src/noop_backend.rs

@@ -1,5 +1,5 @@
 use std::io;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use crate::{Metadata, ReadDir, VfsBackend, VfsEvent};
 
@@ -15,45 +15,43 @@ impl NoopBackend {
 
 impl VfsBackend for NoopBackend {
     fn read(&mut self, _path: &Path) -> io::Result<Vec<u8>> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "NoopBackend doesn't do anything",
-        ))
+        Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
     fn write(&mut self, _path: &Path, _data: &[u8]) -> io::Result<()> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "NoopBackend doesn't do anything",
-        ))
+        Err(io::Error::other("NoopBackend doesn't do anything"))
+    }
+
+    fn exists(&mut self, _path: &Path) -> io::Result<bool> {
+        Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
     fn read_dir(&mut self, _path: &Path) -> io::Result<ReadDir> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "NoopBackend doesn't do anything",
-        ))
+        Err(io::Error::other("NoopBackend doesn't do anything"))
+    }
+
+    fn create_dir(&mut self, _path: &Path) -> io::Result<()> {
+        Err(io::Error::other("NoopBackend doesn't do anything"))
+    }
+
+    fn create_dir_all(&mut self, _path: &Path) -> io::Result<()> {
+        Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
     fn remove_file(&mut self, _path: &Path) -> io::Result<()> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "NoopBackend doesn't do anything",
-        ))
+        Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
     fn remove_dir_all(&mut self, _path: &Path) -> io::Result<()> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "NoopBackend doesn't do anything",
-        ))
+        Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
     fn metadata(&mut self, _path: &Path) -> io::Result<Metadata> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "NoopBackend doesn't do anything",
-        ))
+        Err(io::Error::other("NoopBackend doesn't do anything"))
+    }
+
+    fn canonicalize(&mut self, _path: &Path) -> io::Result<PathBuf> {
+        Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
@@ -61,17 +59,11 @@ impl VfsBackend for NoopBackend {
     }
 
     fn watch(&mut self, _path: &Path) -> io::Result<()> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "NoopBackend doesn't do anything",
-        ))
+        Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
     fn unwatch(&mut self, _path: &Path) -> io::Result<()> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "NoopBackend doesn't do anything",
-        ))
+        Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 }
 

crates/memofs/src/std_backend.rs

@@ -17,9 +17,9 @@ pub struct StdBackend {
 }
 
 impl StdBackend {
-    pub fn new() -> StdBackend {
+    pub fn new() -> io::Result<StdBackend> {
         let (notify_tx, notify_rx) = mpsc::channel();
-        let watcher = watcher(notify_tx, Duration::from_millis(50)).unwrap();
+        let watcher = watcher(notify_tx, Duration::from_millis(50)).map_err(io::Error::other)?;
 
         let (tx, rx) = crossbeam_channel::unbounded();
 
@@ -46,11 +46,11 @@ impl StdBackend {
             Result::<(), crossbeam_channel::SendError<VfsEvent>>::Ok(())
         });
 
-        Self {
+        Ok(Self {
             watcher,
             watcher_receiver: rx,
             watches: HashSet::new(),
-        }
+        })
     }
 }
 
@@ -63,6 +63,10 @@ impl VfsBackend for StdBackend {
         fs_err::write(path, data)
     }
 
+    fn exists(&mut self, path: &Path) -> io::Result<bool> {
+        std::fs::exists(path)
+    }
+
     fn read_dir(&mut self, path: &Path) -> io::Result<ReadDir> {
         let entries: Result<Vec<_>, _> = fs_err::read_dir(path)?.collect();
         let mut entries = entries?;
@@ -78,6 +82,14 @@ impl VfsBackend for StdBackend {
         })
     }
 
+    fn create_dir(&mut self, path: &Path) -> io::Result<()> {
+        fs_err::create_dir(path)
+    }
+
+    fn create_dir_all(&mut self, path: &Path) -> io::Result<()> {
+        fs_err::create_dir_all(path)
+    }
+
     fn remove_file(&mut self, path: &Path) -> io::Result<()> {
         fs_err::remove_file(path)
     }
@@ -94,6 +106,10 @@ impl VfsBackend for StdBackend {
         })
     }
 
+    fn canonicalize(&mut self, path: &Path) -> io::Result<PathBuf> {
+        fs_err::canonicalize(path)
+    }
+
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
         self.watcher_receiver.clone()
     }
@@ -109,20 +125,12 @@ impl VfsBackend for StdBackend {
             self.watches.insert(path.to_path_buf());
             self.watcher
                 .watch(path, RecursiveMode::Recursive)
-                .map_err(|inner| io::Error::new(io::ErrorKind::Other, inner))
+                .map_err(io::Error::other)
         }
     }
 
     fn unwatch(&mut self, path: &Path) -> io::Result<()> {
         self.watches.remove(path);
-        self.watcher
-            .unwatch(path)
-            .map_err(|inner| io::Error::new(io::ErrorKind::Other, inner))
-    }
-}
-
-impl Default for StdBackend {
-    fn default() -> Self {
-        Self::new()
+        self.watcher.unwatch(path).map_err(io::Error::other)
     }
 }

plugin.project.json

@@ -22,6 +22,9 @@
     },
     "Version": {
       "$path": "plugin/Version.txt"
+    },
+    "UploadDetails": {
+      "$path": "plugin/UploadDetails.json"
     }
   }
 }

plugin/UploadDetails.json

@@ -0,0 +1,7 @@
+{
+  "assetId": 13916111004,
+  "name": "Rojo",
+  "description": "The plugin portion of Rojo, a tool to enable professional tooling for Roblox developers.",
+  "creatorId": 32644114,
+  "creatorType": "Group"
+}

plugin/Version.txt

@@ -1 +1 @@
-7.5.1
+7.7.0-rc.1

plugin/fmt/init.lua

@@ -25,7 +25,7 @@
 local function defaultTableDebug(buffer, input)
 	buffer:writeRaw("{")
 
-	for key, value in pairs(input) do
+	for key, value in input do
 		buffer:write("[{:?}] = {:?}", key, value)
 
 		if next(input, key) ~= nil then
@@ -50,7 +50,7 @@ local function defaultTableDebugExtended(buffer, input)
 	buffer:writeLineRaw("{")
 	buffer:indent()
 
-	for key, value in pairs(input) do
+	for key, value in input do
 		buffer:writeLine("[{:?}] = {:#?},", key, value)
 	end
 

plugin/http/Response.lua

@@ -1,5 +1,7 @@
 local HttpService = game:GetService("HttpService")
 
+local msgpack = require(script.Parent.Parent.msgpack)
+
 local stringTemplate = [[
 Http.Response {
 	code: %d
@@ -31,4 +33,8 @@ function Response:json()
 	return HttpService:JSONDecode(self.body)
 end
 
+function Response:msgpack()
+	return msgpack.decode(self.body)
+end
+
 return Response

plugin/http/init.lua

@@ -1,7 +1,8 @@
 local HttpService = game:GetService("HttpService")
 
-local Promise = require(script.Parent.Promise)
 local Log = require(script.Parent.Log)
+local msgpack = require(script.Parent.msgpack)
+local Promise = require(script.Parent.Promise)
 
 local HttpError = require(script.Error)
 local HttpResponse = require(script.Response)
@@ -13,6 +14,13 @@ local Http = {}
 Http.Error = HttpError
 Http.Response = HttpResponse
 
+-- Monkey patch msgpack.UInt64.new to lossily convert the low and high bits of the integer
+-- to a native Luau number. We should change the upstream decoder to emit a native
+-- integer, once those are live.
+function msgpack.UInt64.new(mostSignificantPart: number, leastSignificantPart: number): number
+	return (mostSignificantPart % 2 ^ 32) * 2 ^ 32 + (leastSignificantPart % 2 ^ 32)
+end
+
 local function performRequest(requestParams)
 	local requestId = lastRequestId + 1
 	lastRequestId = requestId
@@ -68,4 +76,12 @@ function Http.jsonDecode(source)
 	return HttpService:JSONDecode(source)
 end
 
+function Http.msgpackEncode(object)
+	return msgpack.encode(object)
+end
+
+function Http.msgpackDecode(source)
+	return msgpack.decode(source)
+end
+
 return Http

plugin/rbx_dom_lua/EncodedValue.lua

@@ -377,6 +377,18 @@ types = {
 		fromPod = function(pod)
 			if pod == "Default" then
 				return nil
+			else
+				-- Passing `nil` instead of not passing anything gives
+				-- different results, so we have to branch here.
+				if pod.acousticAbsorption then
+					return (PhysicalProperties.new :: any)(
+						pod.density,
+						pod.friction,
+						pod.elasticity,
+						pod.frictionWeight,
+						pod.elasticityWeight,
+						pod.acousticAbsorption
+					)
 				else
 					return PhysicalProperties.new(
 						pod.density,
@@ -386,6 +398,7 @@ types = {
 						pod.elasticityWeight
 					)
 				end
+			end
 		end,
 
 		toPod = function(roblox)
@@ -398,6 +411,7 @@ types = {
 					elasticity = roblox.Elasticity,
 					frictionWeight = roblox.FrictionWeight,
 					elasticityWeight = roblox.ElasticityWeight,
+					acousticAbsorption = roblox.AcousticAbsorption,
 				}
 			end
 		end,

plugin/rbx_dom_lua/allValues.json

@@ -441,7 +441,8 @@
         "friction": 1.0,
         "elasticity": 0.0,
         "frictionWeight": 50.0,
-        "elasticityWeight": 25.0
+        "elasticityWeight": 25.0,
+        "acousticAbsorption": 0.15625
       }
     },
     "ty": "PhysicalProperties"

plugin/rbx_dom_lua/base64.lua

@@ -1,139 +1,10 @@
--- Thanks to Tiffany352 for this base64 implementation!
-
-local floor = math.floor
-local char = string.char
-
-local function encodeBase64(str)
-	local out = {}
-	local nOut = 0
-	local alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
-	local strLen = #str
-
-	-- 3 octets become 4 hextets
-	for i = 1, strLen - 2, 3 do
-		local b1, b2, b3 = str:byte(i, i + 3)
-		local word = b3 + b2 * 256 + b1 * 256 * 256
-
-		local h4 = word % 64 + 1
-		word = floor(word / 64)
-		local h3 = word % 64 + 1
-		word = floor(word / 64)
-		local h2 = word % 64 + 1
-		word = floor(word / 64)
-		local h1 = word % 64 + 1
-
-		out[nOut + 1] = alphabet:sub(h1, h1)
-		out[nOut + 2] = alphabet:sub(h2, h2)
-		out[nOut + 3] = alphabet:sub(h3, h3)
-		out[nOut + 4] = alphabet:sub(h4, h4)
-		nOut = nOut + 4
-	end
-
-	local remainder = strLen % 3
-
-	if remainder == 2 then
-		-- 16 input bits -> 3 hextets (2 full, 1 partial)
-		local b1, b2 = str:byte(-2, -1)
-		-- partial is 4 bits long, leaving 2 bits of zero padding ->
-		-- offset = 4
-		local word = b2 * 4 + b1 * 4 * 256
-
-		local h3 = word % 64 + 1
-		word = floor(word / 64)
-		local h2 = word % 64 + 1
-		word = floor(word / 64)
-		local h1 = word % 64 + 1
-
-		out[nOut + 1] = alphabet:sub(h1, h1)
-		out[nOut + 2] = alphabet:sub(h2, h2)
-		out[nOut + 3] = alphabet:sub(h3, h3)
-		out[nOut + 4] = "="
-	elseif remainder == 1 then
-		-- 8 input bits -> 2 hextets (2 full, 1 partial)
-		local b1 = str:byte(-1, -1)
-		-- partial is 2 bits long, leaving 4 bits of zero padding ->
-		-- offset = 16
-		local word = b1 * 16
-
-		local h2 = word % 64 + 1
-		word = floor(word / 64)
-		local h1 = word % 64 + 1
-
-		out[nOut + 1] = alphabet:sub(h1, h1)
-		out[nOut + 2] = alphabet:sub(h2, h2)
-		out[nOut + 3] = "="
-		out[nOut + 4] = "="
-	end
-	-- if the remainder is 0, then no work is needed
-
-	return table.concat(out, "")
-end
-
-local function decodeBase64(str)
-	local out = {}
-	local nOut = 0
-	local alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
-	local strLen = #str
-	local acc = 0
-	local nAcc = 0
-
-	local alphabetLut = {}
-	for i = 1, #alphabet do
-		alphabetLut[alphabet:sub(i, i)] = i - 1
-	end
-
-	-- 4 hextets become 3 octets
-	for i = 1, strLen do
-		local ch = str:sub(i, i)
-		local byte = alphabetLut[ch]
-		if byte then
-			acc = acc * 64 + byte
-			nAcc = nAcc + 1
-		end
-
-		if nAcc == 4 then
-			local b3 = acc % 256
-			acc = floor(acc / 256)
-			local b2 = acc % 256
-			acc = floor(acc / 256)
-			local b1 = acc % 256
-
-			out[nOut + 1] = char(b1)
-			out[nOut + 2] = char(b2)
-			out[nOut + 3] = char(b3)
-			nOut = nOut + 3
-			nAcc = 0
-			acc = 0
-		end
-	end
-
-	if nAcc == 3 then
-		-- 3 hextets -> 16 bit output
-		acc = acc * 64
-		acc = floor(acc / 256)
-		local b2 = acc % 256
-		acc = floor(acc / 256)
-		local b1 = acc % 256
-
-		out[nOut + 1] = char(b1)
-		out[nOut + 2] = char(b2)
-	elseif nAcc == 2 then
-		-- 2 hextets -> 8 bit output
-		acc = acc * 64
-		acc = floor(acc / 256)
-		acc = acc * 64
-		acc = floor(acc / 256)
-		local b1 = acc % 256
-
-		out[nOut + 1] = char(b1)
-	elseif nAcc == 1 then
-		error("Base64 has invalid length")
-	end
-
-	return table.concat(out, "")
-end
+local EncodingService = game:GetService("EncodingService")
 
 return {
-	decode = decodeBase64,
-	encode = encodeBase64,
+	decode = function(input: string)
+		return buffer.tostring(EncodingService:Base64Decode(buffer.fromstring(input)))
+	end,
+	encode = function(input: string)
+		return buffer.tostring(EncodingService:Base64Encode(buffer.fromstring(input)))
+	end,
 }

plugin/rbx_dom_lua/customProperties.lua

@@ -208,4 +208,30 @@ return {
 			end,
 		},
 	},
+	StyleRule = {
+		PropertiesSerialize = {
+			read = function(instance: StyleRule)
+				return true, instance:GetProperties()
+			end,
+			write = function(instance: StyleRule, _, value: { [any]: any })
+				if typeof(value) ~= "table" then
+					return false, Error.new(Error.Kind.CannotParseBinaryString)
+				end
+
+				local existing = instance:GetProperties()
+
+				for itemName, itemValue in pairs(value) do
+					instance:SetProperty(itemName, itemValue)
+				end
+
+				for existingItemName in pairs(existing) do
+					if value[existingItemName] == nil then
+						instance:SetProperty(existingItemName, nil)
+					end
+				end
+
+				return true
+			end,
+		},
+	},
 }

plugin/run-tests.server.lua

@@ -1,8 +1,8 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 
-local TestEZ = require(ReplicatedStorage.Packages:WaitForChild("TestEZ", 10))
+local TestEZ = require(ReplicatedStorage:WaitForChild("Packages", 10):WaitForChild("TestEZ", 10))
 
-local Rojo = ReplicatedStorage.Rojo
+local Rojo = ReplicatedStorage:WaitForChild("Rojo", 10)
 
 local Settings = require(Rojo.Plugin.Settings)
 Settings:set("logLevel", "Trace")

plugin/src/ApiContext.lua

@@ -1,4 +1,5 @@
 local Packages = script.Parent.Parent.Packages
+local HttpService = game:GetService("HttpService")
 local Http = require(Packages.Http)
 local Log = require(Packages.Log)
 local Promise = require(Packages.Promise)
@@ -9,7 +10,7 @@ local Version = require(script.Parent.Version)
 
 local validateApiInfo = Types.ifEnabled(Types.ApiInfoResponse)
 local validateApiRead = Types.ifEnabled(Types.ApiReadResponse)
-local validateApiSubscribe = Types.ifEnabled(Types.ApiSubscribeResponse)
+local validateApiSocketPacket = Types.ifEnabled(Types.ApiSocketPacket)
 local validateApiSerialize = Types.ifEnabled(Types.ApiSerializeResponse)
 local validateApiRefPatch = Types.ifEnabled(Types.ApiRefPatchResponse)
 
@@ -99,6 +100,7 @@ function ApiContext.new(baseUrl)
 		__baseUrl = baseUrl,
 		__sessionId = nil,
 		__messageCursor = -1,
+		__wsClient = nil,
 		__connected = true,
 		__activeRequests = {},
 	}
@@ -126,6 +128,12 @@ function ApiContext:disconnect()
 		request:cancel()
 	end
 	self.__activeRequests = {}
+
+	if self.__wsClient then
+		Log.trace("Closing WebSocket client")
+		self.__wsClient:Close()
+	end
+	self.__wsClient = nil
 end
 
 function ApiContext:setMessageCursor(index)
@@ -137,7 +145,7 @@ function ApiContext:connect()
 
 	return Http.get(url)
 		:andThen(rejectFailedRequests)
-		:andThen(Http.Response.json)
+		:andThen(Http.Response.msgpack)
 		:andThen(rejectWrongProtocolVersion)
 		:andThen(function(body)
 			assert(validateApiInfo(body))
@@ -155,7 +163,7 @@ end
 function ApiContext:read(ids)
 	local url = ("%s/api/read/%s"):format(self.__baseUrl, table.concat(ids, ","))
 
-	return Http.get(url):andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(body)
+	return Http.get(url):andThen(rejectFailedRequests):andThen(Http.Response.msgpack):andThen(function(body)
 		if body.sessionId ~= self.__sessionId then
 			return Promise.reject("Server changed ID")
 		end
@@ -183,9 +191,9 @@ function ApiContext:write(patch)
 		table.insert(updated, fixedUpdate)
 	end
 
-	-- Only add the 'added' field if the table is non-empty, or else Roblox's
-	-- JSON implementation will turn the table into an array instead of an
-	-- object, causing API validation to fail.
+	-- Only add the 'added' field if the table is non-empty, or else the msgpack
+	-- encode implementation will turn the table into an array instead of a map,
+	-- causing API validation to fail.
 	local added
 	if next(patch.added) ~= nil then
 		added = patch.added
@@ -198,54 +206,84 @@ function ApiContext:write(patch)
 		added = added,
 	}
 
-	body = Http.jsonEncode(body)
+	body = Http.msgpackEncode(body)
 
-	return Http.post(url, body):andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(responseBody)
+	return Http.post(url, body)
+		:andThen(rejectFailedRequests)
+		:andThen(Http.Response.msgpack)
+		:andThen(function(responseBody)
 			Log.info("Write response: {:?}", responseBody)
 
 			return responseBody
 		end)
 end
 
-function ApiContext:retrieveMessages()
-	local url = ("%s/api/subscribe/%s"):format(self.__baseUrl, self.__messageCursor)
+function ApiContext:connectWebSocket(packetHandlers)
+	local url = ("%s/api/socket/%s"):format(self.__baseUrl, self.__messageCursor)
+	-- Convert HTTP/HTTPS URL to WS/WSS
+	url = url:gsub("^http://", "ws://"):gsub("^https://", "wss://")
 
-	local function sendRequest()
-		local request = Http.get(url):catch(function(err)
-			if err.type == Http.Error.Kind.Timeout and self.__connected then
-				return sendRequest()
+	return Promise.new(function(resolve, reject)
+		local success, wsClient =
+			pcall(HttpService.CreateWebStreamClient, HttpService, Enum.WebStreamClientType.WebSocket, {
+				Url = url,
+			})
+		if not success then
+			reject("Failed to create WebSocket client: " .. tostring(wsClient))
+			return
+		end
+		self.__wsClient = wsClient
+
+		local closed, errored, received
+
+		received = self.__wsClient.MessageReceived:Connect(function(msg)
+			local data = Http.msgpackDecode(msg)
+			if data.sessionId ~= self.__sessionId then
+				Log.warn("Received message with wrong session ID; ignoring")
+				return
 			end
 
-			return Promise.reject(err)
+			assert(validateApiSocketPacket(data))
+
+			Log.trace("Received websocket packet: {:#?}", data)
+
+			local handler = packetHandlers[data.packetType]
+			if handler then
+				local ok, err = pcall(handler, data.body)
+				if not ok then
+					Log.error("Error in WebSocket packet handler for type '%s': %s", data.packetType, err)
+				end
+			else
+				Log.warn("No handler for WebSocket packet type '%s'", data.packetType)
+			end
 		end)
 
-		Log.trace("Tracking request {}", request)
-		self.__activeRequests[request] = true
+		closed = self.__wsClient.Closed:Connect(function()
+			closed:Disconnect()
+			errored:Disconnect()
+			received:Disconnect()
 
-		return request:finally(function(...)
-			Log.trace("Cleaning up request {}", request)
-			self.__activeRequests[request] = nil
-			return ...
+			if self.__connected then
+				reject("WebSocket connection closed unexpectedly")
+			else
+				resolve()
+			end
 		end)
-	end
 
-	return sendRequest():andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(body)
-		if body.sessionId ~= self.__sessionId then
-			return Promise.reject("Server changed ID")
-		end
+		errored = self.__wsClient.Error:Connect(function(code, msg)
+			closed:Disconnect()
+			errored:Disconnect()
+			received:Disconnect()
 
-		assert(validateApiSubscribe(body))
-
-		self:setMessageCursor(body.messageCursor)
-
-		return body.messages
+			reject("WebSocket error: " .. code .. " - " .. msg)
+		end)
 	end)
 end
 
 function ApiContext:open(id)
 	local url = ("%s/api/open/%s"):format(self.__baseUrl, id)
 
-	return Http.post(url, ""):andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(body)
+	return Http.post(url, ""):andThen(rejectFailedRequests):andThen(Http.Response.msgpack):andThen(function(body)
 		if body.sessionId ~= self.__sessionId then
 			return Promise.reject("Server changed ID")
 		end
@@ -255,30 +293,38 @@ function ApiContext:open(id)
 end
 
 function ApiContext:serialize(ids: { string })
-	local url = ("%s/api/serialize/%s"):format(self.__baseUrl, table.concat(ids, ","))
+	local url = ("%s/api/serialize"):format(self.__baseUrl)
+	local request_body = Http.msgpackEncode({ sessionId = self.__sessionId, ids = ids })
 
-	return Http.get(url):andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(body)
-		if body.sessionId ~= self.__sessionId then
+	return Http.post(url, request_body)
+		:andThen(rejectFailedRequests)
+		:andThen(Http.Response.msgpack)
+		:andThen(function(response_body)
+			if response_body.sessionId ~= self.__sessionId then
 				return Promise.reject("Server changed ID")
 			end
 
-		assert(validateApiSerialize(body))
+			assert(validateApiSerialize(response_body))
 
-		return body
+			return response_body
 		end)
 end
 
 function ApiContext:refPatch(ids: { string })
-	local url = ("%s/api/ref-patch/%s"):format(self.__baseUrl, table.concat(ids, ","))
+	local url = ("%s/api/ref-patch"):format(self.__baseUrl)
+	local request_body = Http.msgpackEncode({ sessionId = self.__sessionId, ids = ids })
 
-	return Http.get(url):andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(body)
-		if body.sessionId ~= self.__sessionId then
+	return Http.post(url, request_body)
+		:andThen(rejectFailedRequests)
+		:andThen(Http.Response.msgpack)
+		:andThen(function(response_body)
+			if response_body.sessionId ~= self.__sessionId then
 				return Promise.reject("Server changed ID")
 			end
 
-		assert(validateApiRefPatch(body))
+			assert(validateApiRefPatch(response_body))
 
-		return body
+			return response_body
 		end)
 end
 

plugin/src/App/Components/ClassIcon.lua

@@ -1,6 +1,11 @@
 local StudioService = game:GetService("StudioService")
 local AssetService = game:GetService("AssetService")
 
+type CachedImageInfo = {
+	pixels: buffer,
+	size: Vector2,
+}
+
 local Rojo = script:FindFirstAncestor("Rojo")
 local Plugin = Rojo.Plugin
 local Packages = Rojo.Packages
@@ -11,44 +16,71 @@ local e = Roact.createElement
 
 local EditableImage = require(Plugin.App.Components.EditableImage)
 
-local imageCache = {}
-local function getImageSizeAndPixels(image)
-	if not imageCache[image] then
-		local editableImage = AssetService:CreateEditableImageAsync(image)
+local imageCache: { [string]: CachedImageInfo } = {}
+
+local function cloneBuffer(b: buffer): buffer
+	local newBuffer = buffer.create(buffer.len(b))
+	buffer.copy(newBuffer, 0, b)
+	return newBuffer
+end
+
+local function getImageSizeAndPixels(image: string): (Vector2, buffer)
+	local cachedImage = imageCache[image]
+
+	if not cachedImage then
+		local editableImage = AssetService:CreateEditableImageAsync(Content.fromUri(image))
+		local size = editableImage.Size
+		local pixels = editableImage:ReadPixelsBuffer(Vector2.zero, size)
 		imageCache[image] = {
-			Size = editableImage.Size,
-			Pixels = editableImage:ReadPixels(Vector2.zero, editableImage.Size),
+			pixels = pixels,
+			size = size,
 		}
+
+		return size, cloneBuffer(pixels)
 	end
 
-	return imageCache[image].Size, table.clone(imageCache[image].Pixels)
+	return cachedImage.size, cloneBuffer(cachedImage.pixels)
 end
 
 local function getRecoloredClassIcon(className, color)
 	local iconProps = StudioService:GetClassIcon(className)
 
 	if iconProps and color then
-		local success, editableImageSize, editableImagePixels = pcall(function()
-			local size, pixels = getImageSizeAndPixels(iconProps.Image)
+		--stylua: ignore
+		local success, editableImageSize, editableImagePixels = pcall(function(_iconProps: { [any]: any }, _color: Color3): (Vector2, buffer)
+			local size, pixels = getImageSizeAndPixels(_iconProps.Image)
+			local pixelsLen = buffer.len(pixels)
 
 			local minVal, maxVal = math.huge, -math.huge
-			for i = 1, #pixels, 4 do
-				if pixels[i + 3] == 0 then
+
+			for i = 0, pixelsLen, 4 do
+				if buffer.readu8(pixels, i + 3) == 0 then
 					continue
 				end
-				local pixelVal = math.max(pixels[i], pixels[i + 1], pixels[i + 2])
+				local pixelVal = math.max(
+					buffer.readu8(pixels, i),
+					buffer.readu8(pixels, i + 1),
+					buffer.readu8(pixels, i + 2)
+				)
 
 				minVal = math.min(minVal, pixelVal)
 				maxVal = math.max(maxVal, pixelVal)
 			end
 
-			local hue, sat, val = color:ToHSV()
-			for i = 1, #pixels, 4 do
-				if pixels[i + 3] == 0 then
+			local hue, sat, val = _color:ToHSV()
+
+			for i = 0, pixelsLen, 4 do
+				if buffer.readu8(pixels, i + 3) == 0 then
 					continue
 				end
+				local gIndex = i + 1
+				local bIndex = i + 2
 
-				local pixelVal = math.max(pixels[i], pixels[i + 1], pixels[i + 2])
+				local pixelVal = math.max(
+					buffer.readu8(pixels, i),
+					buffer.readu8(pixels, gIndex),
+					buffer.readu8(pixels, bIndex)
+				)
 				local newVal = val
 				if minVal < maxVal then
 					-- Remap minVal - maxVal to val*0.9 - val
@@ -56,10 +88,12 @@ local function getRecoloredClassIcon(className, color)
 				end
 
 				local newPixelColor = Color3.fromHSV(hue, sat, newVal)
-				pixels[i], pixels[i + 1], pixels[i + 2] = newPixelColor.R, newPixelColor.G, newPixelColor.B
+				buffer.writeu8(pixels, i, newPixelColor.R)
+				buffer.writeu8(pixels, gIndex, newPixelColor.G)
+				buffer.writeu8(pixels, bIndex, newPixelColor.B)
 			end
 			return size, pixels
-		end)
+		end, iconProps, color)
 		if success then
 			iconProps.EditableImagePixels = editableImagePixels
 			iconProps.EditableImageSize = editableImageSize

plugin/src/App/Components/CodeLabel.lua

@@ -1,66 +0,0 @@
-local Rojo = script:FindFirstAncestor("Rojo")
-local Plugin = Rojo.Plugin
-local Packages = Rojo.Packages
-
-local Roact = require(Packages.Roact)
-local Highlighter = require(Packages.Highlighter)
-Highlighter.matchStudioSettings()
-
-local e = Roact.createElement
-
-local Theme = require(Plugin.App.Theme)
-
-local CodeLabel = Roact.PureComponent:extend("CodeLabel")
-
-function CodeLabel:init()
-	self.labelRef = Roact.createRef()
-	self.highlightsRef = Roact.createRef()
-end
-
-function CodeLabel:didMount()
-	Highlighter.highlight({
-		textObject = self.labelRef:getValue(),
-	})
-	self:updateHighlights()
-end
-
-function CodeLabel:didUpdate()
-	self:updateHighlights()
-end
-
-function CodeLabel:updateHighlights()
-	local highlights = self.highlightsRef:getValue()
-	if not highlights then
-		return
-	end
-
-	for _, lineLabel in highlights:GetChildren() do
-		local lineNum = tonumber(string.match(lineLabel.Name, "%d+") or "0")
-		lineLabel.BackgroundColor3 = self.props.lineBackground
-		lineLabel.BorderSizePixel = 0
-		lineLabel.BackgroundTransparency = if self.props.markedLines[lineNum] then 0.25 else 1
-	end
-end
-
-function CodeLabel:render()
-	return Theme.with(function(theme)
-		return e("TextLabel", {
-			Size = self.props.size,
-			Position = self.props.position,
-			Text = self.props.text,
-			BackgroundTransparency = 1,
-			FontFace = theme.Font.Code,
-			TextSize = theme.TextSize.Code,
-			TextXAlignment = Enum.TextXAlignment.Left,
-			TextYAlignment = Enum.TextYAlignment.Top,
-			TextColor3 = Color3.fromRGB(255, 255, 255),
-			[Roact.Ref] = self.labelRef,
-		}, {
-			SyntaxHighlights = e("Folder", {
-				[Roact.Ref] = self.highlightsRef,
-			}),
-		})
-	end)
-end
-
-return CodeLabel

plugin/src/App/Components/EditableImage.lua

@@ -12,7 +12,8 @@ function EditableImage:init()
 end
 
 function EditableImage:writePixels()
-	local image = self.ref.current
+	local image = self.ref.current :: EditableImage
+
 	if not image then
 		return
 	end
@@ -20,7 +21,7 @@ function EditableImage:writePixels()
 		return
 	end
 
-	image:WritePixels(Vector2.zero, self.props.size, self.props.pixels)
+	image:WritePixelsBuffer(Vector2.zero, self.props.size, self.props.pixels)
 end
 
 function EditableImage:render()

plugin/src/App/Components/Notifications/FullscreenNotification.lua

@@ -19,9 +19,15 @@ local FullscreenNotification = Roact.Component:extend("FullscreeFullscreenNotifi
 function FullscreenNotification:init()
 	self.transparency, self.setTransparency = Roact.createBinding(0)
 	self.lifetime = self.props.timeout
+	self.dismissed = false
 end
 
 function FullscreenNotification:dismiss()
+	if self.dismissed then
+		return
+	end
+	self.dismissed = true
+
 	if self.props.onClose then
 		self.props.onClose()
 	end
@@ -59,7 +65,7 @@ function FullscreenNotification:didMount()
 end
 
 function FullscreenNotification:willUnmount()
-	if self.timeout and coroutine.status(self.timeout) ~= "dead" then
+	if self.timeout and coroutine.status(self.timeout) == "suspended" then
 		task.cancel(self.timeout)
 	end
 end

plugin/src/App/Components/Notifications/Notification.lua

@@ -25,6 +25,7 @@ function Notification:init()
 	self.binding = bindingUtil.fromMotor(self.motor)
 
 	self.lifetime = self.props.timeout
+	self.dismissed = false
 
 	self.motor:onStep(function(value)
 		if value <= 0 and self.props.onClose then
@@ -34,6 +35,11 @@ function Notification:init()
 end
 
 function Notification:dismiss()
+	if self.dismissed then
+		return
+	end
+	self.dismissed = true
+
 	self.motor:setGoal(Flipper.Spring.new(0, {
 		frequency = 5,
 		dampingRatio = 1,
@@ -75,7 +81,7 @@ function Notification:didMount()
 end
 
 function Notification:willUnmount()
-	if self.timeout and coroutine.status(self.timeout) ~= "dead" then
+	if self.timeout and coroutine.status(self.timeout) == "suspended" then
 		task.cancel(self.timeout)
 	end
 end

plugin/src/App/Components/StringDiffVisualizer/StringDiff.lua

@@ -1,3 +1,4 @@
+--!strict
 --[[
     Based on DiffMatchPatch by Neil Fraser.
     https://github.com/google/diff-match-patch
@@ -67,8 +68,187 @@ function StringDiff.findDiffs(text1: string, text2: string): Diffs
 	end
 
 	-- Cleanup the diff
+	diffs = StringDiff._cleanupSemantic(diffs)
 	diffs = StringDiff._reorderAndMerge(diffs)
 
+	-- Remove any empty diffs
+	local cursor = 1
+	while cursor and diffs[cursor] do
+		if diffs[cursor].value == "" then
+			table.remove(diffs, cursor)
+		else
+			cursor += 1
+		end
+	end
+
+	return diffs
+end
+
+function StringDiff._computeDiff(text1: string, text2: string): Diffs
+	-- Assumes that the prefix and suffix have already been trimmed off
+	-- and shortcut returns have been made so these texts must be different
+
+	local text1Length, text2Length = #text1, #text2
+
+	if text1Length == 0 then
+		-- It's simply inserting all of text2 into text1
+		return { { actionType = StringDiff.ActionTypes.Insert, value = text2 } }
+	end
+
+	if text2Length == 0 then
+		-- It's simply deleting all of text1
+		return { { actionType = StringDiff.ActionTypes.Delete, value = text1 } }
+	end
+
+	local longText = if text1Length > text2Length then text1 else text2
+	local shortText = if text1Length > text2Length then text2 else text1
+	local shortTextLength = #shortText
+
+	-- Shortcut if the shorter string exists entirely inside the longer one
+	local indexOf = if shortTextLength == 0 then nil else string.find(longText, shortText, 1, true)
+	if indexOf ~= nil then
+		local diffs = {
+			{ actionType = StringDiff.ActionTypes.Insert, value = string.sub(longText, 1, indexOf - 1) },
+			{ actionType = StringDiff.ActionTypes.Equal, value = shortText },
+			{ actionType = StringDiff.ActionTypes.Insert, value = string.sub(longText, indexOf + shortTextLength) },
+		}
+		-- Swap insertions for deletions if diff is reversed
+		if text1Length > text2Length then
+			diffs[1].actionType, diffs[3].actionType = StringDiff.ActionTypes.Delete, StringDiff.ActionTypes.Delete
+		end
+		return diffs
+	end
+
+	if shortTextLength == 1 then
+		-- Single character string
+		-- After the previous shortcut, the character can't be an equality
+		return {
+			{ actionType = StringDiff.ActionTypes.Delete, value = text1 },
+			{ actionType = StringDiff.ActionTypes.Insert, value = text2 },
+		}
+	end
+
+	return StringDiff._bisect(text1, text2)
+end
+
+function StringDiff._cleanupSemantic(diffs: Diffs): Diffs
+	-- Reduce the number of edits by eliminating semantically trivial equalities.
+	local changes = false
+	local equalities = {} -- Stack of indices where equalities are found.
+	local equalitiesLength = 0 -- Keeping our own length var is faster.
+	local lastEquality: string? = nil
+	-- Always equal to diffs[equalities[equalitiesLength]].value
+	local pointer = 1 -- Index of current position.
+	-- Number of characters that changed prior to the equality.
+	local length_insertions1 = 0
+	local length_deletions1 = 0
+	-- Number of characters that changed after the equality.
+	local length_insertions2 = 0
+	local length_deletions2 = 0
+
+	while diffs[pointer] do
+		if diffs[pointer].actionType == StringDiff.ActionTypes.Equal then -- Equality found.
+			equalitiesLength = equalitiesLength + 1
+			equalities[equalitiesLength] = pointer
+			length_insertions1 = length_insertions2
+			length_deletions1 = length_deletions2
+			length_insertions2 = 0
+			length_deletions2 = 0
+			lastEquality = diffs[pointer].value
+		else -- An insertion or deletion.
+			if diffs[pointer].actionType == StringDiff.ActionTypes.Insert then
+				length_insertions2 = length_insertions2 + #diffs[pointer].value
+			else
+				length_deletions2 = length_deletions2 + #diffs[pointer].value
+			end
+			-- Eliminate an equality that is smaller or equal to the edits on both
+			-- sides of it.
+			if
+				lastEquality
+				and (#lastEquality <= math.max(length_insertions1, length_deletions1))
+				and (#lastEquality <= math.max(length_insertions2, length_deletions2))
+			then
+				-- Duplicate record.
+				table.insert(
+					diffs,
+					equalities[equalitiesLength],
+					{ actionType = StringDiff.ActionTypes.Delete, value = lastEquality }
+				)
+				-- Change second copy to insert.
+				diffs[equalities[equalitiesLength] + 1].actionType = StringDiff.ActionTypes.Insert
+				-- Throw away the equality we just deleted.
+				equalitiesLength = equalitiesLength - 1
+				-- Throw away the previous equality (it needs to be reevaluated).
+				equalitiesLength = equalitiesLength - 1
+				pointer = (equalitiesLength > 0) and equalities[equalitiesLength] or 0
+				length_insertions1, length_deletions1 = 0, 0 -- Reset the counters.
+				length_insertions2, length_deletions2 = 0, 0
+				lastEquality = nil
+				changes = true
+			end
+		end
+		pointer = pointer + 1
+	end
+
+	-- Normalize the diff.
+	if changes then
+		StringDiff._reorderAndMerge(diffs)
+	end
+	StringDiff._cleanupSemanticLossless(diffs)
+
+	-- Find any overlaps between deletions and insertions.
+	-- e.g: <del>abcxxx</del><ins>xxxdef</ins>
+	--   -> <del>abc</del>xxx<ins>def</ins>
+	-- e.g: <del>xxxabc</del><ins>defxxx</ins>
+	--   -> <ins>def</ins>xxx<del>abc</del>
+	-- Only extract an overlap if it is as big as the edit ahead or behind it.
+	pointer = 2
+	while diffs[pointer] do
+		if
+			diffs[pointer - 1].actionType == StringDiff.ActionTypes.Delete
+			and diffs[pointer].actionType == StringDiff.ActionTypes.Insert
+		then
+			local deletion = diffs[pointer - 1].value
+			local insertion = diffs[pointer].value
+			local overlap_length1 = StringDiff._commonOverlap(deletion, insertion)
+			local overlap_length2 = StringDiff._commonOverlap(insertion, deletion)
+			if overlap_length1 >= overlap_length2 then
+				if overlap_length1 >= #deletion / 2 or overlap_length1 >= #insertion / 2 then
+					-- Overlap found.  Insert an equality and trim the surrounding edits.
+					table.insert(
+						diffs,
+						pointer,
+						{ actionType = StringDiff.ActionTypes.Equal, value = string.sub(insertion, 1, overlap_length1) }
+					)
+					diffs[pointer - 1].value = string.sub(deletion, 1, #deletion - overlap_length1)
+					diffs[pointer + 1].value = string.sub(insertion, overlap_length1 + 1)
+					pointer = pointer + 1
+				end
+			else
+				if overlap_length2 >= #deletion / 2 or overlap_length2 >= #insertion / 2 then
+					-- Reverse overlap found.
+					-- Insert an equality and swap and trim the surrounding edits.
+					table.insert(
+						diffs,
+						pointer,
+						{ actionType = StringDiff.ActionTypes.Equal, value = string.sub(deletion, 1, overlap_length2) }
+					)
+					diffs[pointer - 1] = {
+						actionType = StringDiff.ActionTypes.Insert,
+						value = string.sub(insertion, 1, #insertion - overlap_length2),
+					}
+					diffs[pointer + 1] = {
+						actionType = StringDiff.ActionTypes.Delete,
+						value = string.sub(deletion, overlap_length2 + 1),
+					}
+					pointer = pointer + 1
+				end
+			end
+			pointer = pointer + 1
+		end
+		pointer = pointer + 1
+	end
+
 	return diffs
 end
 
@@ -124,51 +304,164 @@ function StringDiff._sharedSuffix(text1: string, text2: string): number
 	return pointerMid
 end
 
-function StringDiff._computeDiff(text1: string, text2: string): Diffs
-	-- Assumes that the prefix and suffix have already been trimmed off
-	-- and shortcut returns have been made so these texts must be different
+function StringDiff._commonOverlap(text1: string, text2: string): number
+	-- Determine if the suffix of one string is the prefix of another.
 
-	local text1Length, text2Length = #text1, #text2
-
-	if text1Length == 0 then
-		-- It's simply inserting all of text2 into text1
-		return { { actionType = StringDiff.ActionTypes.Insert, value = text2 } }
+	-- Cache the text lengths to prevent multiple calls.
+	local text1_length = #text1
+	local text2_length = #text2
+	-- Eliminate the null case.
+	if text1_length == 0 or text2_length == 0 then
+		return 0
+	end
+	-- Truncate the longer string.
+	if text1_length > text2_length then
+		text1 = string.sub(text1, text1_length - text2_length + 1)
+	elseif text1_length < text2_length then
+		text2 = string.sub(text2, 1, text1_length)
+	end
+	local text_length = math.min(text1_length, text2_length)
+	-- Quick check for the worst case.
+	if text1 == text2 then
+		return text_length
 	end
 
-	if text2Length == 0 then
-		-- It's simply deleting all of text1
-		return { { actionType = StringDiff.ActionTypes.Delete, value = text1 } }
+	-- Start by looking for a single character match
+	-- and increase length until no match is found.
+	-- Performance analysis: https://neil.fraser.name/news/2010/11/04/
+	local best = 0
+	local length = 1
+	while true do
+		local pattern = string.sub(text1, text_length - length + 1)
+		local found = string.find(text2, pattern, 1, true)
+		if found == nil then
+			return best
+		end
+		length = length + found - 1
+		if found == 1 or string.sub(text1, text_length - length + 1) == string.sub(text2, 1, length) then
+			best = length
+			length = length + 1
+		end
+	end
+end
+
+function StringDiff._cleanupSemanticScore(one: string, two: string): number
+	-- Given two strings, compute a score representing whether the internal
+	-- boundary falls on logical boundaries.
+	-- Scores range from 6 (best) to 0 (worst).
+
+	if (#one == 0) or (#two == 0) then
+		-- Edges are the best.
+		return 6
 	end
 
-	local longText = if text1Length > text2Length then text1 else text2
-	local shortText = if text1Length > text2Length then text2 else text1
-	local shortTextLength = #shortText
+	-- Each port of this function behaves slightly differently due to
+	-- subtle differences in each language's definition of things like
+	-- 'whitespace'.  Since this function's purpose is largely cosmetic,
+	-- the choice has been made to use each language's native features
+	-- rather than force total conformity.
+	local char1 = string.sub(one, -1)
+	local char2 = string.sub(two, 1, 1)
+	local nonAlphaNumeric1 = string.match(char1, "%W")
+	local nonAlphaNumeric2 = string.match(char2, "%W")
+	local whitespace1 = nonAlphaNumeric1 and string.match(char1, "%s")
+	local whitespace2 = nonAlphaNumeric2 and string.match(char2, "%s")
+	local lineBreak1 = whitespace1 and string.match(char1, "%c")
+	local lineBreak2 = whitespace2 and string.match(char2, "%c")
+	local blankLine1 = lineBreak1 and string.match(one, "\n\r?\n$")
+	local blankLine2 = lineBreak2 and string.match(two, "^\r?\n\r?\n")
 
-	-- Shortcut if the shorter string exists entirely inside the longer one
-	local indexOf = if shortTextLength == 0 then nil else string.find(longText, shortText, 1, true)
-	if indexOf ~= nil then
-		local diffs = {
-			{ actionType = StringDiff.ActionTypes.Insert, value = string.sub(longText, 1, indexOf - 1) },
-			{ actionType = StringDiff.ActionTypes.Equal, value = shortText },
-			{ actionType = StringDiff.ActionTypes.Insert, value = string.sub(longText, indexOf + shortTextLength) },
-		}
-		-- Swap insertions for deletions if diff is reversed
-		if text1Length > text2Length then
-			diffs[1].actionType, diffs[3].actionType = StringDiff.ActionTypes.Delete, StringDiff.ActionTypes.Delete
+	if blankLine1 or blankLine2 then
+		-- Five points for blank lines.
+		return 5
+	elseif lineBreak1 or lineBreak2 then
+		-- Four points for line breaks
+		-- DEVIATION: Prefer to start on a line break instead of end on it
+		return if lineBreak1 then 4 else 4.5
+	elseif nonAlphaNumeric1 and not whitespace1 and whitespace2 then
+		-- Three points for end of sentences.
+		return 3
+	elseif whitespace1 or whitespace2 then
+		-- Two points for whitespace.
+		return 2
+	elseif nonAlphaNumeric1 or nonAlphaNumeric2 then
+		-- One point for non-alphanumeric.
+		return 1
 	end
-		return diffs
+	return 0
+end
+
+function StringDiff._cleanupSemanticLossless(diffs: Diffs)
+	-- Look for single edits surrounded on both sides by equalities
+	-- which can be shifted sideways to align the edit to a word boundary.
+	-- e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
+
+	local pointer = 2
+	-- Intentionally ignore the first and last element (don't need checking).
+	while diffs[pointer + 1] do
+		local prevDiff, nextDiff = diffs[pointer - 1], diffs[pointer + 1]
+		if
+			(prevDiff.actionType == StringDiff.ActionTypes.Equal)
+			and (nextDiff.actionType == StringDiff.ActionTypes.Equal)
+		then
+			-- This is a single edit surrounded by equalities.
+			local diff = diffs[pointer]
+
+			local equality1 = prevDiff.value
+			local edit = diff.value
+			local equality2 = nextDiff.value
+
+			-- First, shift the edit as far left as possible.
+			local commonOffset = StringDiff._sharedSuffix(equality1, edit)
+			if commonOffset > 0 then
+				local commonString = string.sub(edit, -commonOffset)
+				equality1 = string.sub(equality1, 1, -commonOffset - 1)
+				edit = commonString .. string.sub(edit, 1, -commonOffset - 1)
+				equality2 = commonString .. equality2
 			end
 
-	if shortTextLength == 1 then
-		-- Single character string
-		-- After the previous shortcut, the character can't be an equality
-		return {
-			{ actionType = StringDiff.ActionTypes.Delete, value = text1 },
-			{ actionType = StringDiff.ActionTypes.Insert, value = text2 },
-		}
-	end
+			-- Second, step character by character right, looking for the best fit.
+			local bestEquality1 = equality1
+			local bestEdit = edit
+			local bestEquality2 = equality2
+			local bestScore = StringDiff._cleanupSemanticScore(equality1, edit)
+				+ StringDiff._cleanupSemanticScore(edit, equality2)
 
-	return StringDiff._bisect(text1, text2)
+			while string.byte(edit, 1) == string.byte(equality2, 1) do
+				equality1 = equality1 .. string.sub(edit, 1, 1)
+				edit = string.sub(edit, 2) .. string.sub(equality2, 1, 1)
+				equality2 = string.sub(equality2, 2)
+				local score = StringDiff._cleanupSemanticScore(equality1, edit)
+					+ StringDiff._cleanupSemanticScore(edit, equality2)
+				-- The > (rather than >=) encourages leading rather than trailing whitespace on edits.
+				-- I just think it looks better for indentation changes to start the line,
+				-- since then indenting several lines all have aligned diffs at the start
+				if score > bestScore then
+					bestScore = score
+					bestEquality1 = equality1
+					bestEdit = edit
+					bestEquality2 = equality2
+				end
+			end
+			if prevDiff.value ~= bestEquality1 then
+				-- We have an improvement, save it back to the diff.
+				if #bestEquality1 > 0 then
+					diffs[pointer - 1].value = bestEquality1
+				else
+					table.remove(diffs, pointer - 1)
+					pointer = pointer - 1
+				end
+				diffs[pointer].value = bestEdit
+				if #bestEquality2 > 0 then
+					diffs[pointer + 1].value = bestEquality2
+				else
+					table.remove(diffs, pointer + 1)
+					pointer = pointer - 1
+				end
+			end
+		end
+		pointer = pointer + 1
+	end
 end
 
 function StringDiff._bisect(text1: string, text2: string): Diffs

plugin/src/App/Components/StringDiffVisualizer/init.lua

@@ -5,15 +5,15 @@ local Packages = Rojo.Packages
 local Roact = require(Packages.Roact)
 local Log = require(Packages.Log)
 local Highlighter = require(Packages.Highlighter)
+Highlighter.matchStudioSettings()
 local StringDiff = require(script:FindFirstChild("StringDiff"))
 
 local Timer = require(Plugin.Timer)
 local Theme = require(Plugin.App.Theme)
 local getTextBoundsAsync = require(Plugin.App.getTextBoundsAsync)
 
-local CodeLabel = require(Plugin.App.Components.CodeLabel)
 local BorderedContainer = require(Plugin.App.Components.BorderedContainer)
-local ScrollingFrame = require(Plugin.App.Components.ScrollingFrame)
+local VirtualScroller = require(Plugin.App.Components.VirtualScroller)
 
 local e = Roact.createElement
 
@@ -21,26 +21,29 @@ local StringDiffVisualizer = Roact.Component:extend("StringDiffVisualizer")
 
 function StringDiffVisualizer:init()
 	self.scriptBackground, self.setScriptBackground = Roact.createBinding(Color3.fromRGB(0, 0, 0))
-	self.contentSize, self.setContentSize = Roact.createBinding(Vector2.new(0, 0))
+	self.updateEvent = Instance.new("BindableEvent")
+	self.lineHeight, self.setLineHeight = Roact.createBinding(15)
+	self.canvasPosition, self.setCanvasPosition = Roact.createBinding(Vector2.zero)
+	self.windowWidth, self.setWindowWidth = Roact.createBinding(math.huge)
 
 	-- Ensure that the script background is up to date with the current theme
 	self.themeChangedConnection = settings().Studio.ThemeChanged:Connect(function()
-		task.defer(function()
-			-- Defer to allow Highlighter to process the theme change first
+		-- Delay to allow Highlighter to process the theme change first
+		task.delay(1 / 20, function()
 			self:updateScriptBackground()
+			self:updateDiffs()
+			-- Rerender the virtual list elements
+			self.updateEvent:Fire()
 		end)
 	end)
 
 	self:updateScriptBackground()
-
-	self:setState({
-		add = {},
-		remove = {},
-	})
+	self:updateDiffs()
 end
 
 function StringDiffVisualizer:willUnmount()
 	self.themeChangedConnection:Disconnect()
+	self.updateEvent:Destroy()
 end
 
 function StringDiffVisualizer:updateScriptBackground()
@@ -51,96 +54,188 @@ function StringDiffVisualizer:updateScriptBackground()
 end
 
 function StringDiffVisualizer:didUpdate(previousProps)
-	if previousProps.oldString ~= self.props.oldString or previousProps.newString ~= self.props.newString then
-		local add, remove = self:calculateDiffLines()
-		self:setState({
-			add = add,
-			remove = remove,
-		})
+	if
+		previousProps.currentString ~= self.props.currentString
+		or previousProps.incomingString ~= self.props.incomingString
+	then
+		self:updateDiffs()
 	end
 end
 
-function StringDiffVisualizer:calculateContentSize(theme)
-	local oldString, newString = self.props.oldString, self.props.newString
-
-	local oldStringBounds = getTextBoundsAsync(oldString, theme.Font.Code, theme.TextSize.Code, math.huge)
-	local newStringBounds = getTextBoundsAsync(newString, theme.Font.Code, theme.TextSize.Code, math.huge)
-
-	self.setContentSize(
-		Vector2.new(math.max(oldStringBounds.X, newStringBounds.X), math.max(oldStringBounds.Y, newStringBounds.Y))
-	)
-end
-
-function StringDiffVisualizer:calculateDiffLines()
-	Timer.start("StringDiffVisualizer:calculateDiffLines")
-	local oldString, newString = self.props.oldString, self.props.newString
+function StringDiffVisualizer:updateDiffs()
+	Timer.start("StringDiffVisualizer:updateDiffs")
+	local currentString, incomingString = self.props.currentString, self.props.incomingString
 
 	-- Diff the two texts
 	local startClock = os.clock()
-	local diffs = StringDiff.findDiffs(oldString, newString)
+	local diffs =
+		StringDiff.findDiffs((string.gsub(currentString, "\t", "    ")), (string.gsub(incomingString, "\t", "    ")))
 	local stopClock = os.clock()
 
 	Log.trace(
 		"Diffing {} byte and {} byte strings took {} microseconds and found {} diff sections",
-		#oldString,
-		#newString,
+		#currentString,
+		#incomingString,
 		math.round((stopClock - startClock) * 1000 * 1000),
 		#diffs
 	)
 
-	-- Determine which lines to highlight
-	local add, remove = {}, {}
+	-- Build the rich text lines
+	local currentRichTextLines = Highlighter.buildRichTextLines({
+		src = currentString,
+	})
+	local incomingRichTextLines = Highlighter.buildRichTextLines({
+		src = incomingString,
+	})
 
-	local oldLineNum, newLineNum = 1, 1
+	local maxLines = math.max(#currentRichTextLines, #incomingRichTextLines)
+
+	-- Find the diff locations
+	local currentDiffs, incomingDiffs = {}, {}
+	local firstDiffLineNum = 0
+
+	local currentLineNum, incomingLineNum = 1, 1
+	local currentIdx, incomingIdx = 1, 1
 	for _, diff in diffs do
 		local actionType, text = diff.actionType, diff.value
-		local lines = select(2, string.gsub(text, "\n", "\n"))
+		local lineCount = select(2, string.gsub(text, "\n", "\n"))
+		local lines = string.split(text, "\n")
 
 		if actionType == StringDiff.ActionTypes.Equal then
-			oldLineNum += lines
-			newLineNum += lines
-		elseif actionType == StringDiff.ActionTypes.Insert then
-			if lines > 0 then
-				local textLines = string.split(text, "\n")
-				for i, textLine in textLines do
-					if string.match(textLine, "%S") then
-						add[newLineNum + i - 1] = true
-					end
-				end
+			if lineCount > 0 then
+				-- Jump cursor ahead to last line
+				currentLineNum += lineCount
+				incomingLineNum += lineCount
+				currentIdx = #lines[#lines]
+				incomingIdx = #lines[#lines]
 			else
-				if string.match(text, "%S") then
-					add[newLineNum] = true
+				-- Move along this line
+				currentIdx += #text
+				incomingIdx += #text
 			end
+
+			continue
+		end
+
+		if actionType == StringDiff.ActionTypes.Insert then
+			if firstDiffLineNum == 0 then
+				firstDiffLineNum = incomingLineNum
+			end
+
+			for i, lineText in lines do
+				if i > 1 then
+					-- Move to next line
+					incomingLineNum += 1
+					incomingIdx = 0
+				end
+				if not incomingDiffs[incomingLineNum] then
+					incomingDiffs[incomingLineNum] = {}
+				end
+				-- Mark these characters on this line
+				table.insert(incomingDiffs[incomingLineNum], {
+					start = incomingIdx,
+					stop = incomingIdx + #lineText,
+				})
+				incomingIdx += #lineText
 			end
-			newLineNum += lines
 		elseif actionType == StringDiff.ActionTypes.Delete then
-			if lines > 0 then
-				local textLines = string.split(text, "\n")
-				for i, textLine in textLines do
-					if string.match(textLine, "%S") then
-						remove[oldLineNum + i - 1] = true
+			if firstDiffLineNum == 0 then
+				firstDiffLineNum = currentLineNum
 			end
+
+			for i, lineText in lines do
+				if i > 1 then
+					-- Move to next line
+					currentLineNum += 1
+					currentIdx = 0
 				end
-			else
-				if string.match(text, "%S") then
-					remove[oldLineNum] = true
+				if not currentDiffs[currentLineNum] then
+					currentDiffs[currentLineNum] = {}
 				end
+				-- Mark these characters on this line
+				table.insert(currentDiffs[currentLineNum], {
+					start = currentIdx,
+					stop = currentIdx + #lineText,
+				})
+				currentIdx += #lineText
 			end
-			oldLineNum += lines
 		else
 			Log.warn("Unknown diff action: {} {}", actionType, text)
 		end
 	end
 
 	Timer.stop()
-	return add, remove
+
+	self:setState({
+		maxLines = maxLines,
+		currentRichTextLines = currentRichTextLines,
+		incomingRichTextLines = incomingRichTextLines,
+		currentDiffs = currentDiffs,
+		incomingDiffs = incomingDiffs,
+	})
+
+	-- Scroll to the first diff line
+	task.defer(self.setCanvasPosition, Vector2.new(0, math.max(0, (firstDiffLineNum - 4) * 16)))
 end
 
 function StringDiffVisualizer:render()
-	local oldString, newString = self.props.oldString, self.props.newString
+	local currentDiffs, incomingDiffs = self.state.currentDiffs, self.state.incomingDiffs
+	local currentRichTextLines, incomingRichTextLines =
+		self.state.currentRichTextLines, self.state.incomingRichTextLines
+	local maxLines = self.state.maxLines
 
 	return Theme.with(function(theme)
-		self:calculateContentSize(theme)
+		self.setLineHeight(theme.TextSize.Code)
+
+		-- Calculate the width of the canvas
+		-- (One line at a time to avoid the char limit of getTextBoundsAsync)
+		local canvasWidth = 0
+		for i = 1, maxLines do
+			local currentLine = currentRichTextLines[i]
+			if currentLine and string.find(currentLine, "%S") then
+				local bounds = getTextBoundsAsync(currentLine, theme.Font.Code, theme.TextSize.Code, math.huge, true)
+				if bounds.X > canvasWidth then
+					canvasWidth = bounds.X
+				end
+			end
+			local incomingLine = incomingRichTextLines[i]
+			if incomingLine and string.find(incomingLine, "%S") then
+				local bounds = getTextBoundsAsync(incomingLine, theme.Font.Code, theme.TextSize.Code, math.huge, true)
+				if bounds.X > canvasWidth then
+					canvasWidth = bounds.X
+				end
+			end
+		end
+
+		local lineNumberWidth =
+			getTextBoundsAsync(tostring(maxLines), theme.Font.Code, theme.TextSize.Body, math.huge, true).X
+
+		canvasWidth += lineNumberWidth + 12
+
+		local removalScrollMarkers = {}
+		local insertionScrollMarkers = {}
+		for lineNum in currentDiffs do
+			table.insert(
+				removalScrollMarkers,
+				e("Frame", {
+					Size = UDim2.fromScale(0.5, 1 / maxLines),
+					Position = UDim2.fromScale(0, (lineNum - 1) / maxLines),
+					BorderSizePixel = 0,
+					BackgroundColor3 = theme.Diff.Background.Remove,
+				})
+			)
+		end
+		for lineNum in incomingDiffs do
+			table.insert(
+				insertionScrollMarkers,
+				e("Frame", {
+					Size = UDim2.fromScale(0.5, 1 / maxLines),
+					Position = UDim2.fromScale(0.5, (lineNum - 1) / maxLines),
+					BorderSizePixel = 0,
+					BackgroundColor3 = theme.Diff.Background.Add,
+				})
+			)
+		end
 
 		return e(BorderedContainer, {
 			size = self.props.size,
@@ -159,6 +254,14 @@ function StringDiffVisualizer:render()
 					CornerRadius = UDim.new(0, 5),
 				}),
 			}),
+			Main = e("Frame", {
+				Size = UDim2.new(1, -10, 1, -2),
+				Position = UDim2.new(0, 2, 0, 2),
+				BackgroundTransparency = 1,
+				[Roact.Change.AbsoluteSize] = function(rbx)
+					self.setWindowWidth(rbx.AbsoluteSize.X * 0.5 - 10)
+				end,
+			}, {
 				Separator = e("Frame", {
 					Size = UDim2.new(0, 2, 1, 0),
 					Position = UDim2.new(0.5, 0, 0, 0),
@@ -167,35 +270,180 @@ function StringDiffVisualizer:render()
 					BackgroundColor3 = theme.BorderedContainer.BorderColor,
 					BackgroundTransparency = 0.5,
 				}),
-			Old = e(ScrollingFrame, {
-				position = UDim2.new(0, 2, 0, 2),
-				size = UDim2.new(0.5, -7, 1, -4),
-				scrollingDirection = Enum.ScrollingDirection.XY,
-				transparency = self.props.transparency,
-				contentSize = self.contentSize,
-			}, {
-				Source = e(CodeLabel, {
-					size = UDim2.new(1, 0, 1, 0),
+				Current = e(VirtualScroller, {
 					position = UDim2.new(0, 0, 0, 0),
-					text = oldString,
-					lineBackground = theme.Diff.Background.Remove,
-					markedLines = self.state.remove,
-				}),
-			}),
-			New = e(ScrollingFrame, {
-				position = UDim2.new(0.5, 5, 0, 2),
-				size = UDim2.new(0.5, -7, 1, -4),
-				scrollingDirection = Enum.ScrollingDirection.XY,
+					size = UDim2.new(0.5, -1, 1, 0),
 					transparency = self.props.transparency,
-				contentSize = self.contentSize,
+					count = maxLines,
+					updateEvent = self.updateEvent.Event,
+					canvasWidth = canvasWidth,
+					canvasPosition = self.canvasPosition,
+					onCanvasPositionChanged = self.setCanvasPosition,
+					render = function(i)
+						local lineDiffs = currentDiffs[i]
+						local diffFrames = table.create(if lineDiffs then #lineDiffs else 0)
+
+						-- Show diff markers over the specific changed characters
+						if lineDiffs then
+							local charWidth = math.round(theme.TextSize.Code * 0.5)
+							for diffIdx, diff in lineDiffs do
+								local start, stop = diff.start, diff.stop
+								diffFrames[diffIdx] = e("Frame", {
+									Size = if #lineDiffs == 1
+											and start == 0
+											and stop == 0
+										then UDim2.fromScale(1, 1)
+										else UDim2.new(
+											0,
+											math.max(charWidth * (stop - start), charWidth * 0.4),
+											1,
+											0
+										),
+									Position = UDim2.fromOffset(charWidth * start, 0),
+									BackgroundColor3 = theme.Diff.Background.Remove,
+									BackgroundTransparency = 0.85,
+									BorderSizePixel = 0,
+									ZIndex = -1,
+								})
+							end
+						end
+
+						return Roact.createFragment({
+							LineNumber = e("TextLabel", {
+								Size = UDim2.new(0, lineNumberWidth + 8, 1, 0),
+								Text = i,
+								BackgroundColor3 = Color3.new(0, 0, 0),
+								BackgroundTransparency = 0.9,
+								BorderSizePixel = 0,
+								FontFace = theme.Font.Code,
+								TextSize = theme.TextSize.Body,
+								TextColor3 = if lineDiffs then theme.Diff.Background.Remove else theme.SubTextColor,
+								TextXAlignment = Enum.TextXAlignment.Right,
 							}, {
-				Source = e(CodeLabel, {
-					size = UDim2.new(1, 0, 1, 0),
-					position = UDim2.new(0, 0, 0, 0),
-					text = newString,
-					lineBackground = theme.Diff.Background.Add,
-					markedLines = self.state.add,
+								Padding = e("UIPadding", { PaddingRight = UDim.new(0, 6) }),
 							}),
+							Content = e("Frame", {
+								Size = UDim2.new(1, -(lineNumberWidth + 10), 1, 0),
+								Position = UDim2.fromScale(1, 0),
+								AnchorPoint = Vector2.new(1, 0),
+								BackgroundColor3 = theme.Diff.Background.Remove,
+								BackgroundTransparency = if lineDiffs then 0.95 else 1,
+								BorderSizePixel = 0,
+							}, {
+								CodeLabel = e("TextLabel", {
+									Size = UDim2.fromScale(1, 1),
+									Position = UDim2.fromScale(0, 0),
+									Text = currentRichTextLines[i] or "",
+									RichText = true,
+									BackgroundTransparency = 1,
+									BorderSizePixel = 0,
+									FontFace = theme.Font.Code,
+									TextSize = theme.TextSize.Code,
+									TextXAlignment = Enum.TextXAlignment.Left,
+									TextYAlignment = Enum.TextYAlignment.Top,
+									TextColor3 = Color3.fromRGB(255, 255, 255),
+								}),
+								DiffFrames = Roact.createFragment(diffFrames),
+							}),
+						})
+					end,
+					getHeightBinding = function()
+						return self.lineHeight
+					end,
+				}),
+				Incoming = e(VirtualScroller, {
+					position = UDim2.new(0.5, 1, 0, 0),
+					size = UDim2.new(0.5, -1, 1, 0),
+					transparency = self.props.transparency,
+					count = maxLines,
+					updateEvent = self.updateEvent.Event,
+					canvasWidth = canvasWidth,
+					canvasPosition = self.canvasPosition,
+					onCanvasPositionChanged = self.setCanvasPosition,
+					render = function(i)
+						local lineDiffs = incomingDiffs[i]
+						local diffFrames = table.create(if lineDiffs then #lineDiffs else 0)
+
+						-- Show diff markers over the specific changed characters
+						if lineDiffs then
+							local charWidth = math.round(theme.TextSize.Code * 0.5)
+							for diffIdx, diff in lineDiffs do
+								local start, stop = diff.start, diff.stop
+								diffFrames[diffIdx] = e("Frame", {
+									Size = if #lineDiffs == 1
+											and start == 0
+											and stop == 0
+										then UDim2.fromScale(1, 1)
+										else UDim2.new(
+											0,
+											math.max(charWidth * (stop - start), charWidth * 0.4),
+											1,
+											0
+										),
+									Position = UDim2.fromOffset(charWidth * start, 0),
+									BackgroundColor3 = theme.Diff.Background.Add,
+									BackgroundTransparency = 0.85,
+									BorderSizePixel = 0,
+									ZIndex = -1,
+								})
+							end
+						end
+
+						return Roact.createFragment({
+							LineNumber = e("TextLabel", {
+								Size = UDim2.new(0, lineNumberWidth + 8, 1, 0),
+								Text = i,
+								BackgroundColor3 = Color3.new(0, 0, 0),
+								BackgroundTransparency = 0.9,
+								BorderSizePixel = 0,
+								FontFace = theme.Font.Code,
+								TextSize = theme.TextSize.Body,
+								TextColor3 = if lineDiffs then theme.Diff.Background.Add else theme.SubTextColor,
+								TextXAlignment = Enum.TextXAlignment.Right,
+							}, {
+								Padding = e("UIPadding", { PaddingRight = UDim.new(0, 6) }),
+							}),
+							Content = e("Frame", {
+								Size = UDim2.new(1, -(lineNumberWidth + 10), 1, 0),
+								Position = UDim2.fromScale(1, 0),
+								AnchorPoint = Vector2.new(1, 0),
+								BackgroundColor3 = theme.Diff.Background.Add,
+								BackgroundTransparency = if lineDiffs then 0.95 else 1,
+								BorderSizePixel = 0,
+							}, {
+								CodeLabel = e("TextLabel", {
+									Size = UDim2.fromScale(1, 1),
+									Position = UDim2.fromScale(0, 0),
+									Text = incomingRichTextLines[i] or "",
+									RichText = true,
+									BackgroundColor3 = theme.Diff.Background.Add,
+									BackgroundTransparency = 1,
+									BorderSizePixel = 0,
+									FontFace = theme.Font.Code,
+									TextSize = theme.TextSize.Code,
+									TextXAlignment = Enum.TextXAlignment.Left,
+									TextYAlignment = Enum.TextYAlignment.Top,
+									TextColor3 = Color3.fromRGB(255, 255, 255),
+								}),
+								DiffFrames = Roact.createFragment(diffFrames),
+							}),
+						})
+					end,
+					getHeightBinding = function()
+						return self.lineHeight
+					end,
+				}),
+			}),
+			ScrollMarkers = e("Frame", {
+				Size = self.windowWidth:map(function(windowWidth)
+					return UDim2.new(0, 8, 1, -4 - (if canvasWidth > windowWidth then 10 else 0))
+				end),
+				Position = UDim2.new(1, -2, 0, 2),
+				AnchorPoint = Vector2.new(1, 0),
+				BackgroundTransparency = 1,
+			}, {
+				insertions = Roact.createFragment(insertionScrollMarkers),
+				removals = Roact.createFragment(removalScrollMarkers),
 			}),
 		})
 	end)

plugin/src/App/Components/VirtualScroller.lua

@@ -15,8 +15,10 @@ local VirtualScroller = Roact.Component:extend("VirtualScroller")
 function VirtualScroller:init()
 	self.scrollFrameRef = Roact.createRef()
 	self:setState({
-		WindowSize = Vector2.new(),
-		CanvasPosition = Vector2.new(),
+		WindowSize = Vector2.zero,
+		CanvasPosition = if self.props.canvasPosition
+			then self.props.canvasPosition:getValue() or Vector2.zero
+			else Vector2.zero,
 	})
 
 	self.totalCanvas, self.setTotalCanvas = Roact.createBinding(0)
@@ -41,6 +43,10 @@ function VirtualScroller:didMount()
 
 	local canvasPositionSignal = rbx:GetPropertyChangedSignal("CanvasPosition")
 	self.canvasPositionChanged = canvasPositionSignal:Connect(function()
+		if self.props.onCanvasPositionChanged then
+			pcall(self.props.onCanvasPositionChanged, rbx.CanvasPosition)
+		end
+
 		if math.abs(rbx.CanvasPosition.Y - self.state.CanvasPosition.Y) > 5 then
 			self:setState({ CanvasPosition = rbx.CanvasPosition })
 			self:refresh()
@@ -134,8 +140,9 @@ function VirtualScroller:render()
 			BackgroundColor3 = props.backgroundColor3 or theme.BorderedContainer.BackgroundColor,
 			BorderColor3 = props.borderColor3 or theme.BorderedContainer.BorderColor,
 			CanvasSize = self.totalCanvas:map(function(s)
-				return UDim2.fromOffset(0, s)
+				return UDim2.fromOffset(props.canvasWidth or 0, s)
 			end),
+			CanvasPosition = self.props.canvasPosition,
 			ScrollBarThickness = 9,
 			ScrollBarImageColor3 = theme.ScrollBarColor,
 			ScrollBarImageTransparency = props.transparency:map(function(value)
@@ -146,7 +153,7 @@ function VirtualScroller:render()
 			BottomImage = Assets.Images.ScrollBar.Bottom,
 
 			ElasticBehavior = Enum.ElasticBehavior.Always,
-			ScrollingDirection = Enum.ScrollingDirection.Y,
+			ScrollingDirection = Enum.ScrollingDirection.XY,
 			VerticalScrollBarInset = Enum.ScrollBarInset.ScrollBar,
 			[Roact.Ref] = self.scrollFrameRef,
 		}, {

plugin/src/App/StatusPages/Confirming.lua

@@ -4,8 +4,6 @@ local Packages = Rojo.Packages
 
 local Roact = require(Packages.Roact)
 
-local Timer = require(Plugin.Timer)
-local PatchTree = require(Plugin.PatchTree)
 local Settings = require(Plugin.Settings)
 local Theme = require(Plugin.App.Theme)
 local TextButton = require(Plugin.App.Components.TextButton)
@@ -24,36 +22,13 @@ function ConfirmingPage:init()
 	self.containerSize, self.setContainerSize = Roact.createBinding(Vector2.new(0, 0))
 
 	self:setState({
-		patchTree = nil,
 		showingStringDiff = false,
-		oldString = "",
-		newString = "",
+		currentString = "",
+		incomingString = "",
 		showingTableDiff = false,
 		oldTable = {},
 		newTable = {},
 	})
-
-	if self.props.confirmData and self.props.confirmData.patch and self.props.confirmData.instanceMap then
-		self:buildPatchTree()
-	end
-end
-
-function ConfirmingPage:didUpdate(prevProps)
-	if prevProps.confirmData ~= self.props.confirmData then
-		self:buildPatchTree()
-	end
-end
-
-function ConfirmingPage:buildPatchTree()
-	Timer.start("ConfirmingPage:buildPatchTree")
-	self:setState({
-		patchTree = PatchTree.build(
-			self.props.confirmData.patch,
-			self.props.confirmData.instanceMap,
-			{ "Property", "Current", "Incoming" }
-		),
-	})
-	Timer.stop()
 end
 
 function ConfirmingPage:render()
@@ -79,13 +54,13 @@ function ConfirmingPage:render()
 				transparency = self.props.transparency,
 				layoutOrder = 3,
 
-				patchTree = self.state.patchTree,
+				patchTree = self.props.patchTree,
 
-				showStringDiff = function(oldString: string, newString: string)
+				showStringDiff = function(currentString: string, incomingString: string)
 					self:setState({
 						showingStringDiff = true,
-						oldString = oldString,
-						newString = newString,
+						currentString = currentString,
+						incomingString = incomingString,
 					})
 				end,
 				showTableDiff = function(oldTable: { [any]: any? }, newTable: { [any]: any? })
@@ -192,8 +167,8 @@ function ConfirmingPage:render()
 							anchorPoint = Vector2.new(0, 0),
 							transparency = self.props.transparency,
 
-							oldString = self.state.oldString,
-							newString = self.state.newString,
+							currentString = self.state.currentString,
+							incomingString = self.state.incomingString,
 						}),
 					}),
 				}),

plugin/src/App/StatusPages/Connected.lua

@@ -307,8 +307,8 @@ function ConnectedPage:init()
 		renderChanges = false,
 		hoveringChangeInfo = false,
 		showingStringDiff = false,
-		oldString = "",
-		newString = "",
+		currentString = "",
+		incomingString = "",
 	})
 
 	self.changeInfoText, self.setChangeInfoText = Roact.createBinding("")
@@ -511,11 +511,11 @@ function ConnectedPage:render()
 							patchData = self.props.patchData,
 							patchTree = self.props.patchTree,
 							serveSession = self.props.serveSession,
-							showStringDiff = function(oldString: string, newString: string)
+							showStringDiff = function(currentString: string, incomingString: string)
 								self:setState({
 									showingStringDiff = true,
-									oldString = oldString,
-									newString = newString,
+									currentString = currentString,
+									incomingString = incomingString,
 								})
 							end,
 							showTableDiff = function(oldTable: { [any]: any? }, newTable: { [any]: any? })
@@ -566,8 +566,8 @@ function ConnectedPage:render()
 							anchorPoint = Vector2.new(0, 0),
 							transparency = self.props.transparency,
 
-							oldString = self.state.oldString,
-							newString = self.state.newString,
+							currentString = self.state.currentString,
+							incomingString = self.state.incomingString,
 						}),
 					}),
 				}),

plugin/src/App/StatusPages/Connecting.lua

@@ -4,6 +4,8 @@ local Packages = Rojo.Packages
 
 local Roact = require(Packages.Roact)
 
+local Theme = require(Plugin.App.Theme)
+
 local Spinner = require(Plugin.App.Components.Spinner)
 
 local e = Roact.createElement
@@ -11,11 +13,35 @@ local e = Roact.createElement
 local ConnectingPage = Roact.Component:extend("ConnectingPage")
 
 function ConnectingPage:render()
-	return e(Spinner, {
+	return Theme.with(function(theme)
+		return e("Frame", {
+			Size = UDim2.new(1, 0, 1, 0),
+			BackgroundTransparency = 1,
+		}, {
+			Spinner = e(Spinner, {
 				position = UDim2.new(0.5, 0, 0.5, 0),
 				anchorPoint = Vector2.new(0.5, 0.5),
 				transparency = self.props.transparency,
+			}),
+			Text = if type(self.props.text) == "string" and #self.props.text > 0
+				then e("TextLabel", {
+					Text = self.props.text,
+					Position = UDim2.new(0.5, 0, 0.5, 30),
+					Size = UDim2.new(1, -40, 0.5, -40),
+					AnchorPoint = Vector2.new(0.5, 0),
+					TextXAlignment = Enum.TextXAlignment.Center,
+					TextYAlignment = Enum.TextYAlignment.Top,
+					RichText = true,
+					FontFace = theme.Font.Thin,
+					TextSize = theme.TextSize.Medium,
+					TextColor3 = theme.SubTextColor,
+					TextTruncate = Enum.TextTruncate.AtEnd,
+					TextTransparency = self.props.transparency,
+					BackgroundTransparency = 1,
 				})
+				else nil,
+		})
+	end)
 end
 
 return ConnectingPage

plugin/src/App/bindingUtil.lua

@@ -44,7 +44,7 @@ end
 local function blendAlpha(alphaValues)
 	local alpha = 0
 
-	for _, value in pairs(alphaValues) do
+	for _, value in alphaValues do
 		alpha = alpha + (1 - alpha) * value
 	end
 

plugin/src/App/init.lua

@@ -174,6 +174,8 @@ function App:init()
 end
 
 function App:willUnmount()
+	self:endSession()
+
 	self.waypointConnection:Disconnect()
 	self.confirmationBindable:Destroy()
 
@@ -299,6 +301,19 @@ function App:setPriorSyncInfo(host: string, port: string, projectName: string)
 	Settings:set("priorEndpoints", priorSyncInfos)
 end
 
+function App:forgetPriorSyncInfo()
+	local priorSyncInfos = Settings:get("priorEndpoints")
+	if not priorSyncInfos then
+		priorSyncInfos = {}
+	end
+
+	local id = tostring(game.PlaceId)
+	priorSyncInfos[id] = nil
+	Log.trace("Erased last used endpoint for {}", game.PlaceId)
+
+	Settings:set("priorEndpoints", priorSyncInfos)
+end
+
 function App:getHostAndPort()
 	local host = self.host:getValue()
 	local port = self.port:getValue()
@@ -433,7 +448,8 @@ function App:checkSyncReminder()
 	self:findActiveServer()
 		:andThen(function(serverInfo, host, port)
 			self:sendSyncReminder(
-				`Project '{serverInfo.projectName}' is serving at {host}:{port}.\nWould you like to connect?`
+				`Project '{serverInfo.projectName}' is serving at {host}:{port}.\nWould you like to connect?`,
+				{ "Connect", "Dismiss" }
 			)
 		end)
 		:catch(function()
@@ -444,7 +460,8 @@ function App:checkSyncReminder()
 
 				local timeSinceSync = timeUtil.elapsedToText(os.time() - priorSyncInfo.timestamp)
 				self:sendSyncReminder(
-					`You synced project '{priorSyncInfo.projectName}' to this place {timeSinceSync}.\nDid you mean to run 'rojo serve' and then connect?`
+					`You synced project '{priorSyncInfo.projectName}' to this place {timeSinceSync}.\nDid you mean to run 'rojo serve' and then connect?`,
+					{ "Connect", "Forget", "Dismiss" }
 				)
 			end
 		end)
@@ -484,12 +501,16 @@ function App:stopSyncReminderPolling()
 	end
 end
 
-function App:sendSyncReminder(message: string)
+function App:sendSyncReminder(message: string, shownActions: { string })
 	local syncReminderMode = Settings:get("syncReminderMode")
 	if syncReminderMode == "None" then
 		return
 	end
 
+	local connectIndex = table.find(shownActions, "Connect")
+	local forgetIndex = table.find(shownActions, "Forget")
+	local dismissIndex = table.find(shownActions, "Dismiss")
+
 	self.dismissSyncReminder = self:addNotification({
 		text = message,
 		timeout = 120,
@@ -498,24 +519,39 @@ function App:sendSyncReminder(message: string)
 			self.dismissSyncReminder = nil
 		end,
 		actions = {
-			Connect = {
+			Connect = if connectIndex
+				then {
 					text = "Connect",
 					style = "Solid",
-				layoutOrder = 1,
+					layoutOrder = connectIndex,
 					onClick = function()
 						self:startSession()
 					end,
-			},
-			Dismiss = {
+				}
+				else nil,
+			Forget = if forgetIndex
+				then {
+					text = "Forget",
+					style = "Bordered",
+					layoutOrder = forgetIndex,
+					onClick = function()
+						-- The user doesn't want to be reminded again about this sync
+						self:forgetPriorSyncInfo()
+					end,
+				}
+				else nil,
+			Dismiss = if dismissIndex
+				then {
 					text = "Dismiss",
 					style = "Bordered",
-				layoutOrder = 2,
+					layoutOrder = dismissIndex,
 					onClick = function()
 						-- If the user dismisses the reminder,
 						-- then we don't need to remind them again
 						self:stopSyncReminderPolling()
 					end,
-			},
+				}
+				else nil,
 		},
 	})
 end
@@ -595,6 +631,12 @@ function App:startSession()
 		twoWaySync = Settings:get("twoWaySync"),
 	})
 
+	serveSession:setUpdateLoadingTextCallback(function(text: string)
+		self:setState({
+			connectingText = text,
+		})
+	end)
+
 	self.cleanupPrecommit = serveSession:hookPrecommit(function(patch, instanceMap)
 		-- Build new tree for patch
 		self:setState({
@@ -602,44 +644,30 @@ function App:startSession()
 		})
 	end)
 	self.cleanupPostcommit = serveSession:hookPostcommit(function(patch, instanceMap, unappliedPatch)
-		-- Update tree with unapplied metadata
-		self:setState(function(prevState)
-			return {
-				patchTree = PatchTree.updateMetadata(prevState.patchTree, patch, instanceMap, unappliedPatch),
-			}
-		end)
-	end)
-
-	serveSession:hookPostcommit(function(patch, _instanceMap, unapplied)
 		local now = DateTime.now().UnixTimestamp
-		local old = self.state.patchData
+		self:setState(function(prevState)
+			local oldPatchData = prevState.patchData
+			local newPatchData = {
+				patch = patch,
+				unapplied = unappliedPatch,
+				timestamp = now,
+			}
 
 			if PatchSet.isEmpty(patch) then
-			-- Ignore empty patch, but update timestamp
-			self:setState({
-				patchData = {
-					patch = old.patch,
-					unapplied = old.unapplied,
-					timestamp = now,
-				},
-			})
-			return
+				-- Keep existing patch info, but use new timestamp
+				newPatchData.patch = oldPatchData.patch
+				newPatchData.unapplied = oldPatchData.unapplied
+			elseif now - oldPatchData.timestamp < 2 then
+				-- Patches that apply in the same second are combined for human clarity
+				newPatchData.patch = PatchSet.assign(PatchSet.newEmpty(), oldPatchData.patch, patch)
+				newPatchData.unapplied = PatchSet.assign(PatchSet.newEmpty(), oldPatchData.unapplied, unappliedPatch)
 			end
 
-		if now - old.timestamp < 2 then
-			-- Patches that apply in the same second are
-			-- considered to be part of the same change for human clarity
-			patch = PatchSet.assign(PatchSet.newEmpty(), old.patch, patch)
-			unapplied = PatchSet.assign(PatchSet.newEmpty(), old.unapplied, unapplied)
-		end
-
-		self:setState({
-			patchData = {
-				patch = patch,
-				unapplied = unapplied,
-				timestamp = now,
-			},
-		})
+			return {
+				patchTree = PatchTree.updateMetadata(prevState.patchTree, patch, instanceMap, unappliedPatch),
+				patchData = newPatchData,
+			}
+		end)
 	end)
 
 	serveSession:onStatusChanged(function(status, details)
@@ -773,11 +801,13 @@ function App:startSession()
 			end
 		end
 
+		self:setState({
+			connectingText = "Computing diff view...",
+		})
 		self:setState({
 			appStatus = AppStatus.Confirming,
+			patchTree = PatchTree.build(patch, instanceMap, { "Property", "Current", "Incoming" }),
 			confirmData = {
-				instanceMap = instanceMap,
-				patch = patch,
 				serverInfo = serverInfo,
 			},
 			toolbarIcon = Assets.Images.PluginButton,
@@ -888,6 +918,7 @@ function App:render()
 
 					ConfirmingPage = createPageElement(AppStatus.Confirming, {
 						confirmData = self.state.confirmData,
+						patchTree = self.state.patchTree,
 						createPopup = not self.state.guiEnabled,
 
 						onAbort = function()
@@ -901,7 +932,9 @@ function App:render()
 						end,
 					}),
 
-					Connecting = createPageElement(AppStatus.Connecting),
+					Connecting = createPageElement(AppStatus.Connecting, {
+						text = self.state.connectingText,
+					}),
 
 					Connected = createPageElement(AppStatus.Connected, {
 						projectName = self.state.projectName,

plugin/src/Assets.lua

@@ -74,7 +74,7 @@ local Assets = {
 local function guardForTypos(name, map)
 	strict(name, map)
 
-	for key, child in pairs(map) do
+	for key, child in map do
 		if type(child) == "table" then
 			guardForTypos(("%s.%s"):format(name, key), child)
 		end

plugin/src/ChangeBatcher/createPatchSet.lua

@@ -15,7 +15,7 @@ local encodePatchUpdate = require(script.Parent.encodePatchUpdate)
 return function(instanceMap, propertyChanges)
 	local patch = PatchSet.newEmpty()
 
-	for instance, properties in pairs(propertyChanges) do
+	for instance, properties in propertyChanges do
 		local instanceId = instanceMap.fromInstances[instance]
 
 		if instanceId == nil then

plugin/src/ChangeBatcher/encodePatchUpdate.lua

@@ -10,7 +10,7 @@ return function(instance, instanceId, properties)
 		changedProperties = {},
 	}
 
-	for propertyName in pairs(properties) do
+	for propertyName in properties do
 		if propertyName == "Name" then
 			update.changedName = instance.Name
 		else

plugin/src/Config.lua

@@ -21,7 +21,7 @@ return strict("Config", {
 	codename = "Epiphany",
 	version = realVersion,
 	expectedServerVersionString = ("%d.%d or newer"):format(realVersion[1], realVersion[2]),
-	protocolVersion = 4,
+	protocolVersion = 5,
 	defaultHost = "localhost",
 	defaultPort = "34872",
 })

plugin/src/Dictionary.lua

@@ -14,7 +14,7 @@ local function merge(...)
 		local source = select(i, ...)
 
 		if source ~= nil then
-			for key, value in pairs(source) do
+			for key, value in source do
 				if value == None then
 					output[key] = nil
 				else

plugin/src/InstanceMap.lua

@@ -63,7 +63,7 @@ function InstanceMap:__fmtDebug(output)
 	-- Collect all of the entries in the InstanceMap and sort them by their
 	-- label, which helps make our output deterministic.
 	local entries = {}
-	for id, instance in pairs(self.fromIds) do
+	for id, instance in self.fromIds do
 		local label = string.format("%s (%s)", instance:GetFullName(), instance.ClassName)
 
 		table.insert(entries, { id, label })
@@ -73,7 +73,7 @@ function InstanceMap:__fmtDebug(output)
 		return a[2] < b[2]
 	end)
 
-	for _, entry in ipairs(entries) do
+	for _, entry in entries do
 		output:writeLine("{}: {}", entry[1], entry[2])
 	end
 
@@ -227,7 +227,7 @@ function InstanceMap:__disconnectSignals(instance)
 		-- around the extra table. ValueBase objects force us to use multiple
 		-- signals to emulate the Instance.Changed event, however.
 		if typeof(signals) == "table" then
-			for _, signal in ipairs(signals) do
+			for _, signal in signals do
 				signal:Disconnect()
 			end
 		else

plugin/src/PatchTree.lua

@@ -16,6 +16,14 @@ local Types = require(Plugin.Types)
 local decodeValue = require(Plugin.Reconciler.decodeValue)
 local getProperty = require(Plugin.Reconciler.getProperty)
 
+local function yieldIfNeeded(clock)
+	if os.clock() - clock > 1 / 20 then
+		task.wait()
+		return os.clock()
+	end
+	return clock
+end
+
 local function alphabeticalNext(t, state)
 	-- Equivalent of the next function, but returns the keys in the alphabetic
 	-- order of node names. We use a temporary ordered key table that is stored in the
@@ -132,7 +140,6 @@ end
 -- props must contain id, and cannot contain children or parentId
 -- other than those three, it can hold anything
 function Tree:addNode(parent, props)
-	Timer.start("Tree:addNode")
 	assert(props.id, "props must contain id")
 
 	parent = parent or "ROOT"
@@ -143,7 +150,6 @@ function Tree:addNode(parent, props)
 		for k, v in props do
 			node[k] = v
 		end
-		Timer.stop()
 		return node
 	end
 
@@ -154,25 +160,25 @@ function Tree:addNode(parent, props)
 	local parentNode = self:getNode(parent)
 	if not parentNode then
 		Log.warn("Failed to create node since parent doesnt exist: {}, {}", parent, props)
-		Timer.stop()
 		return
 	end
 
 	parentNode.children[node.id] = node
 	self.idToNode[node.id] = node
 
-	Timer.stop()
 	return node
 end
 
 -- Given a list of ancestor ids in descending order, builds the nodes for them
 -- using the patch and instanceMap info
 function Tree:buildAncestryNodes(previousId: string?, ancestryIds: { string }, patch, instanceMap)
-	Timer.start("Tree:buildAncestryNodes")
+	local clock = os.clock()
 	-- Build nodes for ancestry by going up the tree
 	previousId = previousId or "ROOT"
 
 	for _, ancestorId in ancestryIds do
+		clock = yieldIfNeeded(clock)
+
 		local value = instanceMap.fromIds[ancestorId] or patch.added[ancestorId]
 		if not value then
 			Log.warn("Failed to find ancestor object for " .. ancestorId)
@@ -186,8 +192,6 @@ function Tree:buildAncestryNodes(previousId: string?, ancestryIds: { string }, p
 		})
 		previousId = ancestorId
 	end
-
-	Timer.stop()
 end
 
 local PatchTree = {}
@@ -196,12 +200,16 @@ local PatchTree = {}
 -- uses changeListHeaders in node.changeList
 function PatchTree.build(patch, instanceMap, changeListHeaders)
 	Timer.start("PatchTree.build")
+	local clock = os.clock()
+
 	local tree = Tree.new()
 
 	local knownAncestors = {}
 
 	Timer.start("patch.updated")
 	for _, change in patch.updated do
+		clock = yieldIfNeeded(clock)
+
 		local instance = instanceMap.fromIds[change.id]
 		if not instance then
 			continue
@@ -281,6 +289,8 @@ function PatchTree.build(patch, instanceMap, changeListHeaders)
 
 	Timer.start("patch.removed")
 	for _, idOrInstance in patch.removed do
+		clock = yieldIfNeeded(clock)
+
 		local instance = if Types.RbxId(idOrInstance) then instanceMap.fromIds[idOrInstance] else idOrInstance
 		if not instance then
 			-- If we're viewing a past patch, the instance is already removed
@@ -325,6 +335,8 @@ function PatchTree.build(patch, instanceMap, changeListHeaders)
 
 	Timer.start("patch.added")
 	for id, change in patch.added do
+		clock = yieldIfNeeded(clock)
+
 		-- Gather ancestors from existing DOM or future additions
 		local ancestryIds = {}
 		local parentId = change.Parent

plugin/src/Reconciler/countMatchingProperties.lua

@@ -0,0 +1,44 @@
+--[[
+	Counts how many of a virtual instance's properties match the live values on a
+	candidate Roblox instance. `hydrate` uses this to break ties when several
+	existing children share the same Name and ClassName.
+
+	This mirrors the read -> decode -> compare flow that `diff` uses, reusing the
+	same `getProperty`, `decodeValue`, and `trueEquals` helpers.
+]]
+
+local getProperty = require(script.Parent.getProperty)
+local decodeValue = require(script.Parent.decodeValue)
+local trueEquals = require(script.Parent.trueEquals)
+
+local function countMatchingProperties(instance, virtualInstance, instanceMap)
+	local score = 0
+
+	for propertyName, virtualValue in virtualInstance.Properties do
+		-- Skip refs. During hydration the instanceMap is still being built
+		-- top-down, so a ref may point at an instance we haven't hydrated yet
+		-- and therefore can't decode reliably. Refs are also a poor
+		-- disambiguator between same-named siblings.
+		if next(virtualValue) == "Ref" then
+			continue
+		end
+
+		local getSuccess, existingValue = getProperty(instance, propertyName)
+		if not getSuccess then
+			continue
+		end
+
+		local decodeSuccess, decodedValue = decodeValue(virtualValue, instanceMap)
+		if not decodeSuccess then
+			continue
+		end
+
+		if trueEquals(existingValue, decodedValue) then
+			score += 1
+		end
+	end
+
+	return score
+end
+
+return countMatchingProperties

plugin/src/Reconciler/countMatchingProperties.spec.lua

@@ -0,0 +1,91 @@
+return function()
+	local countMatchingProperties = require(script.Parent.countMatchingProperties)
+
+	local InstanceMap = require(script.Parent.Parent.InstanceMap)
+
+	it("counts properties whose values match the instance", function()
+		local instance = Instance.new("StringValue")
+		instance.Value = "hello"
+
+		local virtualInstance = {
+			ClassName = "StringValue",
+			Name = "Value",
+			Properties = {
+				Value = { String = "hello" },
+			},
+			Children = {},
+		}
+
+		expect(countMatchingProperties(instance, virtualInstance, InstanceMap.new())).to.equal(1)
+	end)
+
+	it("does not count properties whose values differ", function()
+		local instance = Instance.new("StringValue")
+		instance.Value = "hello"
+
+		local virtualInstance = {
+			ClassName = "StringValue",
+			Name = "Value",
+			Properties = {
+				Value = { String = "different" },
+			},
+			Children = {},
+		}
+
+		expect(countMatchingProperties(instance, virtualInstance, InstanceMap.new())).to.equal(0)
+	end)
+
+	it("counts multiple matching properties independently", function()
+		local instance = Instance.new("Part")
+		instance.Anchored = true
+		instance.CanCollide = false
+
+		local virtualInstance = {
+			ClassName = "Part",
+			Name = "Part",
+			Properties = {
+				Anchored = { Bool = true },
+				CanCollide = { Bool = false },
+			},
+			Children = {},
+		}
+
+		expect(countMatchingProperties(instance, virtualInstance, InstanceMap.new())).to.equal(2)
+
+		-- Flip one so only a single property matches.
+		instance.CanCollide = true
+		expect(countMatchingProperties(instance, virtualInstance, InstanceMap.new())).to.equal(1)
+	end)
+
+	it("skips unknown properties without counting or erroring", function()
+		local instance = Instance.new("Folder")
+
+		local virtualInstance = {
+			ClassName = "Folder",
+			Name = "Folder",
+			Properties = {
+				FAKE_PROPERTY = { String = "nope" },
+			},
+			Children = {},
+		}
+
+		expect(countMatchingProperties(instance, virtualInstance, InstanceMap.new())).to.equal(0)
+	end)
+
+	it("skips Ref properties without counting or erroring", function()
+		local instance = Instance.new("ObjectValue")
+
+		local virtualInstance = {
+			ClassName = "ObjectValue",
+			Name = "ObjectValue",
+			Properties = {
+				-- A ref must be skipped rather than decoded: during hydration
+				-- the target may not be in the map yet.
+				Value = { Ref = "00000000000000000000000000000000" },
+			},
+			Children = {},
+		}
+
+		expect(countMatchingProperties(instance, virtualInstance, InstanceMap.new())).to.equal(0)
+	end)
+end

plugin/src/Reconciler/diff.lua

@@ -10,100 +10,12 @@ local invariant = require(script.Parent.Parent.invariant)
 local getProperty = require(script.Parent.getProperty)
 local Error = require(script.Parent.Error)
 local decodeValue = require(script.Parent.decodeValue)
+local trueEquals = require(script.Parent.trueEquals)
 
 local function isEmpty(table)
 	return next(table) == nil
 end
 
-local function fuzzyEq(a: number, b: number, epsilon: number): boolean
-	return math.abs(a - b) < epsilon
-end
-
-local function trueEquals(a, b): boolean
-	-- Exit early for simple equality values
-	if a == b then
-		return true
-	end
-
-	-- Treat nil and { Ref = "000...0" } as equal
-	if
-		(a == nil and type(b) == "table" and b.Ref == "00000000000000000000000000000000")
-		or (b == nil and type(a) == "table" and a.Ref == "00000000000000000000000000000000")
-	then
-		return true
-	end
-
-	local typeA, typeB = typeof(a), typeof(b)
-
-	-- For tables, try recursive deep equality
-	if typeA == "table" and typeB == "table" then
-		local checkedKeys = {}
-		for key, value in pairs(a) do
-			checkedKeys[key] = true
-			if not trueEquals(value, b[key]) then
-				return false
-			end
-		end
-		for key, value in pairs(b) do
-			if checkedKeys[key] then
-				continue
-			end
-			if not trueEquals(value, a[key]) then
-				return false
-			end
-		end
-		return true
-
-	-- For numbers, compare with epsilon of 0.0001 to avoid floating point inequality
-	elseif typeA == "number" and typeB == "number" then
-		return fuzzyEq(a, b, 0.0001)
-
-	-- For EnumItem->number, compare the EnumItem's value
-	elseif typeA == "number" and typeB == "EnumItem" then
-		return a == b.Value
-	elseif typeA == "EnumItem" and typeB == "number" then
-		return a.Value == b
-
-	-- For Color3s, compare to RGB ints to avoid floating point inequality
-	elseif typeA == "Color3" and typeB == "Color3" then
-		local aR, aG, aB = math.floor(a.R * 255), math.floor(a.G * 255), math.floor(a.B * 255)
-		local bR, bG, bB = math.floor(b.R * 255), math.floor(b.G * 255), math.floor(b.B * 255)
-		return aR == bR and aG == bG and aB == bB
-
-	-- For CFrames, compare to components with epsilon of 0.0001 to avoid floating point inequality
-	elseif typeA == "CFrame" and typeB == "CFrame" then
-		local aComponents, bComponents = { a:GetComponents() }, { b:GetComponents() }
-		for i, aComponent in aComponents do
-			if not fuzzyEq(aComponent, bComponents[i], 0.0001) then
-				return false
-			end
-		end
-		return true
-
-	-- For Vector3s, compare to components with epsilon of 0.0001 to avoid floating point inequality
-	elseif typeA == "Vector3" and typeB == "Vector3" then
-		local aComponents, bComponents = { a.X, a.Y, a.Z }, { b.X, b.Y, b.Z }
-		for i, aComponent in aComponents do
-			if not fuzzyEq(aComponent, bComponents[i], 0.0001) then
-				return false
-			end
-		end
-		return true
-
-	-- For Vector2s, compare to components with epsilon of 0.0001 to avoid floating point inequality
-	elseif typeA == "Vector2" and typeB == "Vector2" then
-		local aComponents, bComponents = { a.X, a.Y }, { b.X, b.Y }
-		for i, aComponent in aComponents do
-			if not fuzzyEq(aComponent, bComponents[i], 0.0001) then
-				return false
-			end
-		end
-		return true
-	end
-
-	return false
-end
-
 local function shouldDeleteUnknownInstances(virtualInstance)
 	if virtualInstance.Metadata ~= nil then
 		return not virtualInstance.Metadata.ignoreUnknownInstances

plugin/src/Reconciler/diff.spec.lua

@@ -14,7 +14,7 @@ return function()
 	local function size(dict)
 		local len = 0
 
-		for _ in pairs(dict) do
+		for _ in dict do
 			len = len + 1
 		end
 

plugin/src/Reconciler/hydrate.lua

@@ -3,9 +3,22 @@
 	concrete instances and assigning them IDs.
 ]]
 
-local invariant = require(script.Parent.Parent.invariant)
+local Packages = script.Parent.Parent.Parent.Packages
+local Log = require(Packages.Log)
 
-local function hydrate(instanceMap, virtualInstances, rootId, rootInstance)
+local invariant = require(script.Parent.Parent.invariant)
+local countMatchingProperties = require(script.Parent.countMatchingProperties)
+
+-- When several existing children share a Name and ClassName we disambiguate
+-- them by scoring how well each one's properties match the virtual instance.
+-- That scoring is far more expensive than a Name/ClassName check, so we only do
+-- it for reasonably-sized groups. Larger groups (e.g. a folder with thousands of
+-- identically-named parts) fall back to the original order-based matching, which
+-- bounds the added work to roughly MAX_CANDIDATES_TO_SCORE^2 property reads per
+-- group regardless of how large the group is.
+local MAX_CANDIDATES_TO_SCORE = 32
+
+local function hydrateInner(stats, instanceMap, virtualInstances, rootId, rootInstance)
 	local virtualInstance = virtualInstances[rootId]
 
 	if virtualInstance == nil then
@@ -13,38 +26,163 @@ local function hydrate(instanceMap, virtualInstances, rootId, rootInstance)
 	end
 
 	instanceMap:insert(rootId, rootInstance)
+	stats.hydrated += 1
 
 	local existingChildren = rootInstance:GetChildren()
 
-	-- For each existing child, we'll track whether it's been paired with an
-	-- instance that the Rojo server knows about.
-	local isExistingChildVisited = {}
-	for i = 1, #existingChildren do
-		isExistingChildVisited[i] = false
+	-- Group existing children by Name then ClassName so each virtual child can
+	-- find its candidate matches without scanning every sibling. This is what
+	-- keeps hydration fast for parents with thousands of children. Nesting the
+	-- two tables (rather than a combined key) keeps the Name and ClassName checks
+	-- exact, with no way for one to bleed into the other.
+	local buckets = {}
+	for _, childInstance in existingChildren do
+		-- We guard accessing Name and ClassName in order to avoid tripping over
+		-- children of DataModel that Rojo won't have permissions to access at all.
+		local accessSuccess, name, className = pcall(function()
+			return childInstance.Name, childInstance.ClassName
+		end)
+		if not accessSuccess then
+			continue
 		end
 
+		local bucketsByClassName = buckets[name]
+		if bucketsByClassName == nil then
+			bucketsByClassName = {}
+			buckets[name] = bucketsByClassName
+		end
+
+		local bucket = bucketsByClassName[className]
+		if bucket == nil then
+			bucket = { cursor = 1, instances = {} }
+			bucketsByClassName[className] = bucket
+		end
+
+		table.insert(bucket.instances, childInstance)
+	end
+
+	-- Tracks which existing children have already been paired, so one instance
+	-- isn't matched to two different virtual instances.
+	local visited = {}
+
 	for _, childId in ipairs(virtualInstance.Children) do
 		local virtualChild = virtualInstances[childId]
 
-		for childIndex, childInstance in ipairs(existingChildren) do
-			if not isExistingChildVisited[childIndex] then
-				-- We guard accessing Name and ClassName in order to avoid
-				-- tripping over children of DataModel that Rojo won't have
-				-- permissions to access at all.
-				local accessSuccess, name, className = pcall(function()
-					return childInstance.Name, childInstance.ClassName
-				end)
+		local bucketsByClassName = buckets[virtualChild.Name]
+		local bucket = bucketsByClassName and bucketsByClassName[virtualChild.ClassName]
+		if bucket == nil then
+			-- No existing instance matches; diff will mark this id for creation.
+			Log.trace(
+				"hydrate: no existing instance matches {} ({}) for id {}",
+				virtualChild.Name,
+				virtualChild.ClassName,
+				childId
+			)
+			continue
+		end
 
-				-- This rule is very conservative and could be loosened in the
-				-- future, or more heuristics could be introduced.
-				if accessSuccess and name == virtualChild.Name and className == virtualChild.ClassName then
-					isExistingChildVisited[childIndex] = true
-					hydrate(instanceMap, virtualInstances, childId, childInstance)
-					break
+		local instances = bucket.instances
+
+		-- Advance past any leading children that have already been paired. The
+		-- cursor makes order-based matching amortized O(1) per child even for
+		-- very large groups, rather than rescanning the visited prefix.
+		while bucket.cursor <= #instances and visited[instances[bucket.cursor]] do
+			bucket.cursor += 1
+		end
+		if bucket.cursor > #instances then
+			-- Every matching instance has already been paired with an earlier id.
+			Log.trace(
+				"hydrate: no unpaired instance left for {} ({}) for id {}",
+				virtualChild.Name,
+				virtualChild.ClassName,
+				childId
+			)
+			continue
+		end
+
+		-- The cursor points at the earliest unvisited child, so the slots from
+		-- here to the end bound how many candidates remain. Visited children
+		-- after the cursor (gaps) only appear once a group is small enough to be
+		-- scored -- the order-based path below always takes the earliest, which
+		-- keeps the visited region a contiguous prefix. So whenever this count
+		-- exceeds the cap it is exact, and we can pick the earliest match without
+		-- collecting anything.
+		local remaining = #instances - bucket.cursor + 1
+
+		local match
+		if remaining > MAX_CANDIDATES_TO_SCORE then
+			-- Too many to score affordably; take the earliest in child order,
+			-- reproducing the original Name + ClassName behavior.
+			match = instances[bucket.cursor]
+			Log.trace(
+				"hydrate: {} candidates named {} ({}) exceeds the scoring cap of {}; matching id {} by child order",
+				remaining,
+				virtualChild.Name,
+				virtualChild.ClassName,
+				MAX_CANDIDATES_TO_SCORE,
+				childId
+			)
+		else
+			-- Collect the (at most `remaining`) unvisited candidates.
+			local candidates = {}
+			for index = bucket.cursor, #instances do
+				local childInstance = instances[index]
+				if not visited[childInstance] then
+					table.insert(candidates, childInstance)
 				end
 			end
+
+			if #candidates == 1 then
+				-- Only one candidate, so there's nothing to disambiguate.
+				match = candidates[1]
+			else
+				-- Break the tie by choosing the candidate whose properties best
+				-- match the virtual instance, falling back to the earliest in
+				-- child order when scores are equal.
+				local bestScore = -1
+				for _, childInstance in candidates do
+					local score = countMatchingProperties(childInstance, virtualChild, instanceMap)
+					if score > bestScore then
+						bestScore = score
+						match = childInstance
 					end
 				end
+
+				stats.ambiguousGroups += 1
+				stats.candidatesScored += #candidates
+				Log.trace(
+					"hydrate: disambiguated {} candidates named {} ({}) for id {} by property match (best score {})",
+					#candidates,
+					virtualChild.Name,
+					virtualChild.ClassName,
+					childId,
+					bestScore
+				)
+			end
+		end
+
+		visited[match] = true
+		hydrateInner(stats, instanceMap, virtualInstances, childId, match)
+	end
+end
+
+local function hydrate(instanceMap, virtualInstances, rootId, rootInstance)
+	-- Tallies of the work hydration did, surfaced in a single debug log below so
+	-- the cost of property-based disambiguation is visible without per-node spam.
+	local stats = {
+		hydrated = 0,
+		ambiguousGroups = 0,
+		candidatesScored = 0,
+	}
+
+	hydrateInner(stats, instanceMap, virtualInstances, rootId, rootInstance)
+
+	Log.debug(
+		"Hydrated {} instances ({} ambiguous name+class groups, {} candidates scored)",
+		stats.hydrated,
+		stats.ambiguousGroups,
+		stats.candidatesScored
+	)
 end
 
 return hydrate

plugin/src/Reconciler/hydrate.spec.lua

@@ -126,4 +126,140 @@ return function()
 		expect(knownInstances.fromIds["CHILD1"]).to.equal(child1)
 		expect(knownInstances.fromIds["CHILD2"]).to.equal(child2)
 	end)
+
+	it("should disambiguate duplicate-named siblings by matching properties", function()
+		local knownInstances = InstanceMap.new()
+		local virtualInstances = {
+			ROOT = {
+				ClassName = "Folder",
+				Name = "Root",
+				Properties = {},
+				Children = { "CHILD_A", "CHILD_B" },
+			},
+
+			CHILD_A = {
+				ClassName = "StringValue",
+				Name = "a",
+				Properties = { Value = { String = "first" } },
+				Children = {},
+			},
+
+			CHILD_B = {
+				ClassName = "StringValue",
+				Name = "a",
+				Properties = { Value = { String = "second" } },
+				Children = {},
+			},
+		}
+
+		local rootInstance = Instance.new("Folder")
+
+		-- Created in the reverse order of the virtual children, so a purely
+		-- order-based tiebreak would mis-pair them.
+		local child1 = Instance.new("StringValue")
+		child1.Name = "a"
+		child1.Value = "second"
+		child1.Parent = rootInstance
+
+		local child2 = Instance.new("StringValue")
+		child2.Name = "a"
+		child2.Value = "first"
+		child2.Parent = rootInstance
+
+		hydrate(knownInstances, virtualInstances, "ROOT", rootInstance)
+
+		expect(knownInstances:size()).to.equal(3)
+		expect(knownInstances.fromIds["CHILD_A"]).to.equal(child2)
+		expect(knownInstances.fromIds["CHILD_B"]).to.equal(child1)
+	end)
+
+	it("should fall back to child order for duplicate-named siblings with no distinguishing properties", function()
+		local knownInstances = InstanceMap.new()
+		local virtualInstances = {
+			ROOT = {
+				ClassName = "Folder",
+				Name = "Root",
+				Properties = {},
+				Children = { "CHILD_A", "CHILD_B" },
+			},
+
+			CHILD_A = {
+				ClassName = "Folder",
+				Name = "a",
+				Properties = {},
+				Children = {},
+			},
+
+			CHILD_B = {
+				ClassName = "Folder",
+				Name = "a",
+				Properties = {},
+				Children = {},
+			},
+		}
+
+		local rootInstance = Instance.new("Folder")
+
+		local child1 = Instance.new("Folder")
+		child1.Name = "a"
+		child1.Parent = rootInstance
+
+		local child2 = Instance.new("Folder")
+		child2.Name = "a"
+		child2.Parent = rootInstance
+
+		hydrate(knownInstances, virtualInstances, "ROOT", rootInstance)
+
+		expect(knownInstances:size()).to.equal(3)
+		-- With equal scores the earliest unvisited child wins, preserving the
+		-- original order-based behavior.
+		expect(knownInstances.fromIds["CHILD_A"]).to.equal(child1)
+		expect(knownInstances.fromIds["CHILD_B"]).to.equal(child2)
+	end)
+
+	it("should fall back to child order for very large duplicate-named groups", function()
+		-- More candidates than hydrate is willing to score at once. The group
+		-- must fall back to order-based matching, so virtual child N pairs with
+		-- existing child N regardless of properties.
+		local count = 64
+
+		local knownInstances = InstanceMap.new()
+		local virtualInstances = {
+			ROOT = {
+				ClassName = "Folder",
+				Name = "Root",
+				Properties = {},
+				Children = {},
+			},
+		}
+
+		local rootInstance = Instance.new("Folder")
+
+		local expectedInstances = {}
+		for i = 1, count do
+			local id = "CHILD_" .. i
+			table.insert(virtualInstances.ROOT.Children, id)
+			virtualInstances[id] = {
+				ClassName = "StringValue",
+				Name = "a",
+				-- Distinct values that, if scored, would pair by value rather
+				-- than by order.
+				Properties = { Value = { String = "value " .. i } },
+				Children = {},
+			}
+
+			local child = Instance.new("StringValue")
+			child.Name = "a"
+			child.Value = "value " .. (count - i + 1)
+			child.Parent = rootInstance
+			expectedInstances[id] = child
+		end
+
+		hydrate(knownInstances, virtualInstances, "ROOT", rootInstance)
+
+		expect(knownInstances:size()).to.equal(count + 1)
+		for id, expectedInstance in expectedInstances do
+			expect(knownInstances.fromIds[id]).to.equal(expectedInstance)
+		end
+	end)
 end

plugin/src/Reconciler/reify.lua

@@ -126,7 +126,7 @@ function applyDeferredRefs(instanceMap, deferredRefs, unappliedPatch)
 		})
 	end
 
-	for _, entry in ipairs(deferredRefs) do
+	for _, entry in deferredRefs do
 		local _, refId = next(entry.virtualValue)
 
 		if refId == nil then

plugin/src/Reconciler/reify.spec.lua

@@ -12,7 +12,7 @@ return function()
 	local function size(dict)
 		local len = 0
 
-		for _ in pairs(dict) do
+		for _ in dict do
 			len = len + 1
 		end
 

plugin/src/Reconciler/trueEquals.lua

@@ -0,0 +1,100 @@
+--[[
+	Fuzzy value-equality used to compare a decoded virtual property value against
+	the live value read from a real instance. Shared by `diff` (to decide whether
+	a property changed) and `hydrate` (to score candidate instances).
+]]
+
+local function fuzzyEq(a: number, b: number, epsilon: number): boolean
+	return math.abs(a - b) < epsilon
+end
+
+local function trueEquals(a, b): boolean
+	-- Exit early for simple equality values
+	if a == b then
+		return true
+	end
+
+	-- Treat nil and { Ref = "000...0" } as equal
+	if
+		(a == nil and type(b) == "table" and b.Ref == "00000000000000000000000000000000")
+		or (b == nil and type(a) == "table" and a.Ref == "00000000000000000000000000000000")
+	then
+		return true
+	end
+
+	local typeA, typeB = typeof(a), typeof(b)
+
+	-- For tables, try recursive deep equality
+	if typeA == "table" and typeB == "table" then
+		local checkedKeys = {}
+		for key, value in a do
+			checkedKeys[key] = true
+			if not trueEquals(value, b[key]) then
+				return false
+			end
+		end
+		for key, value in b do
+			if checkedKeys[key] then
+				continue
+			end
+			if not trueEquals(value, a[key]) then
+				return false
+			end
+		end
+		return true
+
+	-- For NaN, check if both values are not equal to themselves
+	elseif a ~= a and b ~= b then
+		return true
+
+	-- For numbers, compare with epsilon of 0.0001 to avoid floating point inequality
+	elseif typeA == "number" and typeB == "number" then
+		return fuzzyEq(a, b, 0.0001)
+
+	-- For EnumItem->number, compare the EnumItem's value
+	elseif typeA == "number" and typeB == "EnumItem" then
+		return a == b.Value
+	elseif typeA == "EnumItem" and typeB == "number" then
+		return a.Value == b
+
+	-- For Color3s, compare to RGB ints to avoid floating point inequality
+	elseif typeA == "Color3" and typeB == "Color3" then
+		local aR, aG, aB = math.floor(a.R * 255), math.floor(a.G * 255), math.floor(a.B * 255)
+		local bR, bG, bB = math.floor(b.R * 255), math.floor(b.G * 255), math.floor(b.B * 255)
+		return aR == bR and aG == bG and aB == bB
+
+	-- For CFrames, compare to components with epsilon of 0.0001 to avoid floating point inequality
+	elseif typeA == "CFrame" and typeB == "CFrame" then
+		local aComponents, bComponents = { a:GetComponents() }, { b:GetComponents() }
+		for i, aComponent in aComponents do
+			if not fuzzyEq(aComponent, bComponents[i], 0.0001) then
+				return false
+			end
+		end
+		return true
+
+	-- For Vector3s, compare to components with epsilon of 0.0001 to avoid floating point inequality
+	elseif typeA == "Vector3" and typeB == "Vector3" then
+		local aComponents, bComponents = { a.X, a.Y, a.Z }, { b.X, b.Y, b.Z }
+		for i, aComponent in aComponents do
+			if not fuzzyEq(aComponent, bComponents[i], 0.0001) then
+				return false
+			end
+		end
+		return true
+
+	-- For Vector2s, compare to components with epsilon of 0.0001 to avoid floating point inequality
+	elseif typeA == "Vector2" and typeB == "Vector2" then
+		local aComponents, bComponents = { a.X, a.Y }, { b.X, b.Y }
+		for i, aComponent in aComponents do
+			if not fuzzyEq(aComponent, bComponents[i], 0.0001) then
+				return false
+			end
+		end
+		return true
+	end
+
+	return false
+end
+
+return trueEquals

plugin/src/ServeSession.lua

@@ -18,6 +18,7 @@ local PatchSet = require(script.Parent.PatchSet)
 local Reconciler = require(script.Parent.Reconciler)
 local strict = require(script.Parent.strict)
 local Settings = require(script.Parent.Settings)
+local orderSwaps = require(script.Parent.orderSwaps)
 
 local Status = strict("Session.Status", {
 	NotStarted = "NotStarted",
@@ -48,6 +49,12 @@ local function debugPatch(object)
 	end)
 end
 
+local function attemptReparent(instance, parent)
+	return pcall(function()
+		instance.Parent = parent
+	end)
+end
+
 local ServeSession = {}
 ServeSession.__index = ServeSession
 
@@ -101,6 +108,7 @@ function ServeSession.new(options)
 		__connections = connections,
 		__precommitCallbacks = {},
 		__postcommitCallbacks = {},
+		__updateLoadingText = function() end,
 	}
 
 	setmetatable(self, ServeSession)
@@ -131,6 +139,14 @@ function ServeSession:setConfirmCallback(callback)
 	self.__userConfirmCallback = callback
 end
 
+function ServeSession:setUpdateLoadingTextCallback(callback)
+	self.__updateLoadingText = callback
+end
+
+function ServeSession:setLoadingText(text: string)
+	self.__updateLoadingText(text)
+end
+
 --[=[
 	Hooks a function to run before patch application.
 	The provided function is called with the incoming patch and an InstanceMap
@@ -175,15 +191,31 @@ end
 
 function ServeSession:start()
 	self:__setStatus(Status.Connecting)
+	self:setLoadingText("Connecting to server...")
 
 	self.__apiContext
 		:connect()
 		:andThen(function(serverInfo)
+			self:setLoadingText("Loading initial data from server...")
 			return self:__initialSync(serverInfo):andThen(function()
+				self:setLoadingText("Starting sync loop...")
 				self:__setStatus(Status.Connected, serverInfo.projectName)
 				self:__applyGameAndPlaceId(serverInfo)
 
-				return self:__mainSyncLoop()
+				return self.__apiContext:connectWebSocket({
+					["messages"] = function(messagesPacket)
+						if self.__status == Status.Disconnected then
+							return
+						end
+
+						Log.debug("Received {} messages from Rojo server", #messagesPacket.messages)
+
+						for _, message in messagesPacket.messages do
+							self:__applyPatch(message)
+						end
+						self.__apiContext:setMessageCursor(messagesPacket.messageCursor)
+					end,
+				})
 			end)
 		end)
 		:catch(function(err)
@@ -289,20 +321,72 @@ function ServeSession:__replaceInstances(idList)
 		return false
 	end
 
+	-- Roblox appends to GetChildren() on every reparent, so the order in which
+	-- we re-parent replacements determines their final sibling order.
+	-- We process ancestors before descendants (so each replacement's
+	-- parent already exists when we re-parent it) and siblings in their original
+	-- GetChildren() order. Because the loop below moves the old instance's
+	-- children into the replacement *before* re-parenting the replacement, this
+	-- rebuilds GetChildren() exactly as it was before the swap.
+	local swaps = {}
 	for id, replacement in replacements do
 		local oldInstance = self.__instanceMap.fromIds[id]
+		if not oldInstance then
+			-- TODO: Why would this happen?
+			Log.warn("Instance {} not found in InstanceMap during sync replacement", id)
+			continue
+		end
+
+		table.insert(swaps, {
+			id = id,
+			replacement = replacement,
+			oldInstance = oldInstance,
+		})
+	end
+
+	for _, swap in orderSwaps(swaps) do
+		local id, replacement, oldInstance = swap.id, swap.replacement, swap.oldInstance
+
 		self.__instanceMap:insert(id, replacement)
 		Log.trace("Swapping Instance {} out via api/models/ endpoint", id)
 		local oldParent = oldInstance.Parent
 		for _, child in oldInstance:GetChildren() do
-			child.Parent = replacement
+			-- Some children cannot be reparented, such as a TouchTransmitter
+			local reparentSuccess, reparentError = attemptReparent(child, replacement)
+			if not reparentSuccess then
+				Log.warn(
+					"Could not reparent child {} of instance {} during sync replacement: {}",
+					child.Name,
+					oldInstance.Name,
+					reparentError
+				)
+			end
 		end
 
-		replacement.Parent = oldParent
 		-- ChangeHistoryService doesn't like it if an Instance has been
 		-- Destroyed. So, we have to accept the potential memory hit and
 		-- just set the parent to `nil`.
-		oldInstance.Parent = nil
+		local deleteSuccess, deleteError = attemptReparent(oldInstance, nil)
+		local replaceSuccess, replaceError = attemptReparent(replacement, oldParent)
+
+		if not (deleteSuccess and replaceSuccess) then
+			Log.warn(
+				"Could not swap instances {} and {} during sync replacement: {}",
+				oldInstance.Name,
+				replacement.Name,
+				(deleteError or "") .. "\n" .. (replaceError or "")
+			)
+
+			-- We need to revert the failed swap to avoid losing the old instance and children.
+			for _, child in replacement:GetChildren() do
+				attemptReparent(child, oldInstance)
+			end
+			attemptReparent(oldInstance, oldParent)
+
+			-- Our replacement should never have existed in the first place, so we can just destroy it.
+			replacement:Destroy()
+			continue
+		end
 
 		if selectionMap[oldInstance] then
 			-- This is a bit funky, but it saves the order of Selection
@@ -349,18 +433,11 @@ function ServeSession:__applyPatch(patch)
 		error(unappliedPatch)
 	end
 
-	if PatchSet.isEmpty(unappliedPatch) then
-		if historyRecording then
-			ChangeHistoryService:FinishRecording(historyRecording, Enum.FinishRecordingOperation.Commit)
-		end
-		return
-	end
-
+	if Settings:get("enableSyncFallback") and not PatchSet.isEmpty(unappliedPatch) then
+		-- Some changes did not apply, let's try replacing them instead
 		local addedIdList = PatchSet.addedIdList(unappliedPatch)
 		local updatedIdList = PatchSet.updatedIdList(unappliedPatch)
 
-	local actualUnappliedPatches = PatchSet.newEmpty()
-	if Settings:get("enableSyncFallback") then
 		Log.debug("ServeSession:__replaceInstances(unappliedPatch.added)")
 		Timer.start("ServeSession:__replaceInstances(unappliedPatch.added)")
 		local addSuccess, unappliedAddedRefs = self:__replaceInstances(addedIdList)
@@ -371,20 +448,18 @@ function ServeSession:__applyPatch(patch)
 		local updateSuccess, unappliedUpdateRefs = self:__replaceInstances(updatedIdList)
 		Timer.stop()
 
+		-- Update the unapplied patch to reflect which Instances were replaced successfully
 		if addSuccess then
 			table.clear(unappliedPatch.added)
-			PatchSet.assign(actualUnappliedPatches, unappliedAddedRefs)
+			PatchSet.assign(unappliedPatch, unappliedAddedRefs)
 		end
 		if updateSuccess then
 			table.clear(unappliedPatch.updated)
-			PatchSet.assign(actualUnappliedPatches, unappliedUpdateRefs)
+			PatchSet.assign(unappliedPatch, unappliedUpdateRefs)
 		end
-	else
-		Log.debug("Skipping ServeSession:__replaceInstances because of setting")
 	end
-	PatchSet.assign(actualUnappliedPatches, unappliedPatch)
 
-	if not PatchSet.isEmpty(actualUnappliedPatches) then
+	if not PatchSet.isEmpty(unappliedPatch) then
 		Log.debug(
 			"Could not apply all changes requested by the Rojo server:\n{}",
 			PatchSet.humanSummary(self.__instanceMap, unappliedPatch)
@@ -396,7 +471,7 @@ function ServeSession:__applyPatch(patch)
 	-- guaranteed to be called after the commit
 	for _, callback in self.__postcommitCallbacks do
 		task.spawn(function()
-			local success, err = pcall(callback, patch, self.__instanceMap, actualUnappliedPatches)
+			local success, err = pcall(callback, patch, self.__instanceMap, unappliedPatch)
 			if not success then
 				Log.warn("Postcommit hook errored: {}", err)
 			end
@@ -418,11 +493,13 @@ function ServeSession:__initialSync(serverInfo)
 		-- For any instances that line up with the Rojo server's view, start
 		-- tracking them in the reconciler.
 		Log.trace("Matching existing Roblox instances to Rojo IDs")
+		self:setLoadingText("Hydrating instance map...")
 		self.__reconciler:hydrate(readResponseBody.instances, serverInfo.rootInstanceId, game)
 
 		-- Calculate the initial patch to apply to the DataModel to catch us
 		-- up to what Rojo thinks the place should look like.
 		Log.trace("Computing changes that plugin needs to make to catch up to server...")
+		self:setLoadingText("Finding differences between server and Studio...")
 		local success, catchUpPatch =
 			self.__reconciler:diff(readResponseBody.instances, serverInfo.rootInstanceId, game)
 
@@ -491,40 +568,6 @@ function ServeSession:__initialSync(serverInfo)
 	end)
 end
 
-function ServeSession:__mainSyncLoop()
-	return Promise.new(function(resolve, reject)
-		while self.__status == Status.Connected do
-			local success, result = self.__apiContext
-				:retrieveMessages()
-				:andThen(function(messages)
-					if self.__status == Status.Disconnected then
-						-- In the time it took to retrieve messages, we disconnected
-						-- so we just resolve immediately without patching anything
-						return
-					end
-
-					Log.trace("Serve session {} retrieved {} messages", tostring(self), #messages)
-
-					for _, message in messages do
-						self:__applyPatch(message)
-					end
-				end)
-				:await()
-
-			if self.__status == Status.Disconnected then
-				-- If we are no longer connected after applying, we stop silently
-				-- without checking for errors as they are no longer relevant
-				break
-			elseif success == false then
-				reject(result)
-			end
-		end
-
-		-- We are no longer connected, so we resolve the promise
-		resolve()
-	end)
-end
-
 function ServeSession:__stopInternal(err)
 	self:__setStatus(Status.Disconnected, err)
 	self.__apiContext:disconnect()

plugin/src/Types.lua

@@ -49,12 +49,21 @@ local ApiReadResponse = t.interface({
 	instances = t.map(RbxId, ApiInstance),
 })
 
-local ApiSubscribeResponse = t.interface({
-	sessionId = t.string,
+local SocketPacketType = t.union(t.literal("messages"))
+
+local MessagesPacket = t.interface({
 	messageCursor = t.number,
 	messages = t.array(ApiSubscribeMessage),
 })
 
+local SocketPacketBody = t.union(MessagesPacket)
+
+local ApiSocketPacket = t.interface({
+	sessionId = t.string,
+	packetType = SocketPacketType,
+	body = SocketPacketBody,
+})
+
 local ApiSerializeResponse = t.interface({
 	sessionId = t.string,
 	modelContents = t.buffer,
@@ -85,7 +94,7 @@ return strict("Types", {
 
 	ApiInfoResponse = ApiInfoResponse,
 	ApiReadResponse = ApiReadResponse,
-	ApiSubscribeResponse = ApiSubscribeResponse,
+	ApiSocketPacket = ApiSocketPacket,
 	ApiError = ApiError,
 
 	ApiInstance = ApiInstance,

plugin/src/orderSwaps.lua

@@ -0,0 +1,44 @@
+--[[
+	Determines the order in which `ServeSession:__replaceInstances` should swap
+	instances so that sibling order is preserved.
+
+	Roblox appends to `GetChildren()` on every reparent, so the order in which we
+	re-parent replacements determines their final sibling order. To rebuild
+	`GetChildren()` exactly as it was before the swap we must:
+
+	* process ancestors before descendants, so each replacement's parent already
+	  exists when we re-parent the replacement, and
+	* process siblings in their original `GetChildren()` order.
+
+	`swaps` is an array of `{ id, replacement, oldInstance }` entries. This sorts
+	the array in place (annotating each entry with `depth`/`siblingIndex`) and
+	returns it.
+]]
+local function orderSwaps(swaps)
+	for _, swap in swaps do
+		local depth = 0
+		local ancestor = swap.oldInstance.Parent
+		while ancestor ~= nil do
+			depth += 1
+			ancestor = ancestor.Parent
+		end
+		swap.depth = depth
+
+		local siblingIndex = 0
+		if swap.oldInstance.Parent ~= nil then
+			siblingIndex = table.find(swap.oldInstance.Parent:GetChildren(), swap.oldInstance) or 0
+		end
+		swap.siblingIndex = siblingIndex
+	end
+
+	table.sort(swaps, function(a, b)
+		if a.depth ~= b.depth then
+			return a.depth < b.depth
+		end
+		return a.siblingIndex < b.siblingIndex
+	end)
+
+	return swaps
+end
+
+return orderSwaps

plugin/src/orderSwaps.spec.lua

@@ -0,0 +1,57 @@
+return function()
+	local orderSwaps = require(script.Parent.orderSwaps)
+
+	it("orders same-named siblings by their original GetChildren order", function()
+		local parent = Instance.new("Model")
+		local a1 = Instance.new("Part")
+		a1.Name = "a"
+		a1.Parent = parent
+		local a2 = Instance.new("Part")
+		a2.Name = "a"
+		a2.Parent = parent
+		local a3 = Instance.new("Part")
+		a3.Name = "a"
+		a3.Parent = parent
+
+		-- Input deliberately out of sibling order.
+		-- orderSwaps must restore the GetChildren() order.
+		local ordered = orderSwaps({
+			{ id = "3", oldInstance = a3 },
+			{ id = "1", oldInstance = a1 },
+			{ id = "2", oldInstance = a2 },
+		})
+
+		expect(ordered[1].oldInstance).to.equal(a1)
+		expect(ordered[2].oldInstance).to.equal(a2)
+		expect(ordered[3].oldInstance).to.equal(a3)
+	end)
+
+	it("orders ancestors before descendants", function()
+		local root = Instance.new("Model")
+		local child = Instance.new("Folder")
+		child.Parent = root
+		local grandchild = Instance.new("Part")
+		grandchild.Parent = child
+
+		local ordered = orderSwaps({
+			{ id = "grandchild", oldInstance = grandchild },
+			{ id = "child", oldInstance = child },
+			{ id = "root", oldInstance = root },
+		})
+
+		expect(ordered[1].oldInstance).to.equal(root)
+		expect(ordered[2].oldInstance).to.equal(child)
+		expect(ordered[3].oldInstance).to.equal(grandchild)
+	end)
+
+	it("returns a single swap unchanged", function()
+		local part = Instance.new("Part")
+
+		local ordered = orderSwaps({
+			{ id = "1", oldInstance = part },
+		})
+
+		expect(#ordered).to.equal(1)
+		expect(ordered[1].oldInstance).to.equal(part)
+	end)
+end

plugin/src/preloadAssets.lua

@@ -9,7 +9,7 @@ local gatherAssetUrlsRecursive
 function gatherAssetUrlsRecursive(currentTable, currentUrls)
 	currentUrls = currentUrls or {}
 
-	for _, value in pairs(currentTable) do
+	for _, value in currentTable do
 		if typeof(value) == "string" then
 			table.insert(currentUrls, value)
 		elseif typeof(value) == "table" then

rojo-test/build-test-snapshots/end_to_end__tests__build__plugin_init.snap

@@ -0,0 +1,27 @@
+---
+source: tests/tests/build.rs
+expression: contents
+---
+<roblox version="4">
+  <Item class="Folder" referent="0">
+    <Properties>
+      <string name="Name">plugin_init</string>
+    </Properties>
+    <Item class="Script" referent="1">
+      <Properties>
+        <string name="Name">lua</string>
+        <token name="RunContext">3</token>
+        <string name="Source"><![CDATA[return "From folder/lua/init.plugin.lua"
+]]></string>
+      </Properties>
+    </Item>
+    <Item class="Script" referent="2">
+      <Properties>
+        <string name="Name">luau</string>
+        <token name="RunContext">3</token>
+        <string name="Source"><![CDATA[return "From folder/luau/init.plugin.luau"
+]]></string>
+      </Properties>
+    </Item>
+  </Item>
+</roblox>

rojo-test/build-tests/plugin_init/default.project.json

@@ -0,0 +1,6 @@
+{
+  "name": "plugin_init",
+  "tree": {
+    "$path": "folder"
+  }
+}

rojo-test/build-tests/plugin_init/folder/lua/init.plugin.lua

@@ -0,0 +1 @@
+return "From folder/lua/init.plugin.lua"

rojo-test/build-tests/plugin_init/folder/luau/init.plugin.luau

@@ -0,0 +1 @@
+return "From folder/luau/init.plugin.luau"

rojo-test/serve-test-snapshots/end_to_end__tests__serve__add_folder_info.snap

@@ -6,7 +6,7 @@ expectedPlaceIds: ~
 gameId: ~
 placeId: ~
 projectName: add_folder
-protocolVersion: 4
+protocolVersion: 5
 rootInstanceId: id-2
 serverVersion: "[server-version]"
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__add_folder_subscribe.snap

@@ -1,9 +1,10 @@
 ---
 source: tests/tests/serve.rs
-expression: "subscribe_response.intern_and_redact(&mut redactions, ())"
+expression: "socket_packet.intern_and_redact(&mut redactions, ())"
 ---
-messageCursor: 1
-messages:
+body:
+  messageCursor: 1
+  messages:
     - added:
         id-3:
           Children: []
@@ -16,4 +17,5 @@ messages:
           Properties: {}
       removed: []
       updated: []
+packetType: messages
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__add_optional_folder.snap

@@ -7,7 +7,7 @@ expectedPlaceIds: ~
 gameId: ~
 placeId: ~
 projectName: optional
-protocolVersion: 4
+protocolVersion: 5
 rootInstanceId: id-2
 serverVersion: "[server-version]"
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__edit_init_info.snap

@@ -6,7 +6,7 @@ expectedPlaceIds: ~
 gameId: ~
 placeId: ~
 projectName: edit_init
-protocolVersion: 4
+protocolVersion: 5
 rootInstanceId: id-2
 serverVersion: "[server-version]"
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__edit_init_subscribe.snap

@@ -1,10 +1,10 @@
 ---
 source: tests/tests/serve.rs
-expression: "subscribe_response.intern_and_redact(&mut redactions, ())"
-
+expression: "socket_packet.intern_and_redact(&mut redactions, ())"
 ---
-messageCursor: 1
-messages:
+body:
+  messageCursor: 1
+  messages:
     - added: {}
       removed: []
       updated:
@@ -15,5 +15,5 @@ messages:
             Source:
               String: "-- Edited contents"
           id: id-2
+packetType: messages
 sessionId: id-1
-

rojo-test/serve-test-snapshots/end_to_end__tests__serve__empty_info.snap

@@ -6,7 +6,7 @@ expectedPlaceIds: ~
 gameId: ~
 placeId: ~
 projectName: empty
-protocolVersion: 4
+protocolVersion: 5
 rootInstanceId: id-2
 serverVersion: "[server-version]"
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__empty_json_model_info.snap

@@ -6,7 +6,7 @@ expectedPlaceIds: ~
 gameId: ~
 placeId: ~
 projectName: empty_folder
-protocolVersion: 4
+protocolVersion: 5
 rootInstanceId: id-2
 serverVersion: "[server-version]"
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__empty_json_model_subscribe.snap

@@ -1,9 +1,10 @@
 ---
 source: tests/tests/serve.rs
-expression: "subscribe_response.intern_and_redact(&mut redactions, ())"
+expression: "socket_packet.intern_and_redact(&mut redactions, ())"
 ---
-messageCursor: 1
-messages:
+body:
+  messageCursor: 1
+  messages:
     - added:
         id-3:
           Children: []
@@ -18,4 +19,5 @@ messages:
               Bool: false
       removed: []
       updated: []
+packetType: messages
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__forced_parent_info.snap

@@ -6,7 +6,7 @@ expectedPlaceIds: ~
 gameId: ~
 placeId: ~
 projectName: forced_parent
-protocolVersion: 4
+protocolVersion: 5
 rootInstanceId: id-2
 serverVersion: "[server-version]"
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__meshpart_with_id_info.snap

@@ -6,7 +6,7 @@ expectedPlaceIds: ~
 gameId: ~
 placeId: ~
 projectName: meshpart
-protocolVersion: 4
+protocolVersion: 5
 rootInstanceId: id-2
 serverVersion: "[server-version]"
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__model_pivot_migration_all.snap

@@ -1,9 +1,10 @@
 ---
 source: tests/tests/serve.rs
-expression: "subscribe_response.intern_and_redact(&mut redactions, ())"
+expression: "socket_packet.intern_and_redact(&mut redactions, ())"
 ---
-messageCursor: 1
-messages:
+body:
+  messageCursor: 1
+  messages:
     - added:
         id-6:
           Children: []
@@ -24,4 +25,5 @@ messages:
           changedName: ~
           changedProperties: {}
           id: id-3
+packetType: messages
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__move_folder_of_stuff_info.snap

@@ -6,7 +6,7 @@ expectedPlaceIds: ~
 gameId: ~
 placeId: ~
 projectName: move_folder_of_stuff
-protocolVersion: 4
+protocolVersion: 5
 rootInstanceId: id-2
 serverVersion: "[server-version]"
 sessionId: id-1

rojo-test/serve-test-snapshots/end_to_end__tests__serve__move_folder_of_stuff_subscribe.snap

@@ -1,10 +1,10 @@
 ---
 source: tests/tests/serve.rs
-expression: "subscribe_response.intern_and_redact(&mut redactions, ())"
-
+expression: "socket_packet.intern_and_redact(&mut redactions, ())"
 ---
-messageCursor: 1
-messages:
+body:
+  messageCursor: 1
+  messages:
     - added:
         id-10:
           Children: []
@@ -137,5 +137,5 @@ messages:
               String: "File #5"
       removed: []
       updated: []
+packetType: messages
 sessionId: id-1
-