Release v7.1.0

* Use session's state instead of existence to determine action

* Retain host/port text

* Use bindings instead of text/ref tunneling

Co-authored-by: Lucien Greathouse <me@lpghatguy.com>

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        rust_version: [stable, "1.46.0"]
+        rust_version: [stable, "1.55.0"]
 
     steps:
     - uses: actions/checkout@v1

CHANGELOG.md

@@ -2,7 +2,52 @@
 
 ## Unreleased Changes
 
-## [7.0.0-rc.1][7.0.0-rc.1] (August 23, 2021)
+## [7.1.0] - May 22, 2022
+* Added support for specifying an address to be used by default in project files. ([#507])
+* Added support for optional paths in project files. ([#472])
+* Added support for the new Open Cloud API when uploading. ([#504])
+* Added `sourcemap` command for generating sourcemaps to feed into other tools. ([#530])
+* Added PluginActions for connecting/disconnecting a session ([#537])
+* Added changing toolbar icon to indicate state ([#538])
+
+[#472]: https://github.com/rojo-rbx/rojo/pull/472
+[#504]: https://github.com/rojo-rbx/rojo/pull/504
+[#507]: https://github.com/rojo-rbx/rojo/pull/507
+[#530]: https://github.com/rojo-rbx/rojo/pull/530
+[#537]: https://github.com/rojo-rbx/rojo/pull/537
+[#538]: https://github.com/rojo-rbx/rojo/pull/538
+[7.1.0]: https://github.com/rojo-rbx/rojo/releases/tag/v7.1.0
+
+## [7.0.0] - December 10, 2021
+* Fixed Rojo's interactions with properties enabled by FFlags that are not yet enabled. ([#493])
+* Improved output in Roblox Studio plugin when bad property data is encountered.
+* Reintroduced support for CFrame shorthand syntax in Rojo project and `.meta.json` files, matching Rojo 6. ([#430])
+* Connection settings are now remembered when reconnecting in Roblox Studio. ([#500])
+* Updated reflection database to Roblox v503.
+
+[#430]: https://github.com/rojo-rbx/rojo/issues/430
+[#493]: https://github.com/rojo-rbx/rojo/pull/493
+[#500]: https://github.com/rojo-rbx/rojo/pull/500
+[7.0.0]: https://github.com/rojo-rbx/rojo/releases/tag/v7.0.0
+
+## [7.0.0-rc.3] - October 19, 2021
+This is the last release candidate for Rojo 7. In an effort to get Rojo 7 out the door, we'll be freezing features from here on out, something we should've done a couple months ago.
+
+Expect to see Rojo 7 stable soon!
+
+* Added support for writing `Tags` in project files, model files, and meta files. ([#484])
+* Adjusted Studio plugin colors to match Roblox Studio palette. ([#482])
+* Improved experimental two-way sync feature by batching changes. ([#478])
+
+[#482]: https://github.com/rojo-rbx/rojo/pull/482
+[#484]: https://github.com/rojo-rbx/rojo/pull/484
+[#478]: https://github.com/rojo-rbx/rojo/pull/478
+[7.0.0-rc.3]: https://github.com/rojo-rbx/rojo/releases/tag/v7.0.0-rc.3
+
+## 7.0.0-rc.2 - October 19, 2021
+(Botched release due to Git mishap, oops!)
+
+## [7.0.0-rc.1] - August 23, 2021
 In Rojo 6 and previous Rojo 7 alphas, an explicit Vector3 property would be written like this:
 
 ```json
@@ -45,9 +90,9 @@ The shorthand property format that most users use is not impacted. For reference
 * Added the `fmt-project` subcommand for formatting Rojo project files.
 * Improved error output for many subcommands.
 * Updated to stable versions of rbx-dom libraries.
-* Updated async infrastructure, which should fix a handful of bugs. ([#459][#459])
-* Fixed syncing refs in the Roblox Studio plugin ([#462][#462], [#466][#466])
-* Added support for long paths on Windows. ([#464][#464])
+* Updated async infrastructure, which should fix a handful of bugs. ([#459])
+* Fixed syncing refs in the Roblox Studio plugin ([#462], [#466])
+* Added support for long paths on Windows. ([#464])
 
 [#459]: https://github.com/rojo-rbx/rojo/pull/459
 [#462]: https://github.com/rojo-rbx/rojo/pull/462
@@ -58,7 +103,7 @@ The shorthand property format that most users use is not impacted. For reference
 ## [7.0.0-alpha.4][7.0.0-alpha.4] (May 5, 2021)
 * Added the `gameId` and `placeId` optional properties to project files.
     * When connecting from the Rojo Roblox Studio plugin, Rojo will set the game and place ID of the current place to these values, if set.
-    * This is equivalent to running `game:SetUniverseId(...)` and `game:SetPlaceId(...)` from the command bar in Studio. 
+    * This is equivalent to running `game:SetUniverseId(...)` and `game:SetPlaceId(...)` from the command bar in Studio.
 * Added "EXPERIMENTAL!" label to two-way sync toggle in Rojo's Roblox Studio plugin.
 * Fixed `Name` and `Parent` properties being allowed in Rojo projects. ([#413][pr-413])
 * Fixed "Open Scripts Externally" feature crashing Studio. ([#369][issue-369])

CONTRIBUTING.md

@@ -29,25 +29,31 @@ Sometimes there's something that Rojo doesn't do that it probably should.
 
 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.
+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:
 
 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 double-check tests
+3. Run `cargo test` to update `Cargo.lock` and run tests
 4. Update [`CHANGELOG.md`](CHANGELOG.md)
 5. Commit!
     * `git add . && git commit -m "Release vX.Y.Z"`
-6. Tag the commit with the version from `Cargo.toml` prepended with a v, like `v0.4.13`
+6. Tag the commit
+    * `git tag vX.Y.Z`
 7. Publish the CLI
     * `cargo publish`
 8. Publish the Plugin
-    * `rojo publish plugin --asset_id 6415005344`
-    * `rojo build plugin -o Rojo.rbxm`
+    * `cargo run -- upload plugin --asset_id 6415005344`
+    * `cargo run -- build plugin --output Rojo.rbxm`
 9. Push commits and tags
     * `git push && git push --tags`
 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)
     * Write a small summary of each major feature
-    * Attach release artifacts from GitHub Actions for each platform
+    * Attach release artifacts from GitHub Actions for each platform

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rojo"
-version = "7.0.0-rc.1"
+version = "7.1.0"
 authors = ["Lucien Greathouse <me@lpghatguy.com>"]
 description = "Enables professional-grade development tools for Roblox developers"
 license = "MPL-2.0"
@@ -37,10 +37,6 @@ members = [
 name = "librojo"
 path = "src/lib.rs"
 
-[[bin]]
-name = "rojo"
-path = "src/bin.rs"
-
 [[bench]]
 name = "build"
 harness = false
@@ -55,41 +51,41 @@ memofs = { version = "0.2.0", path = "memofs" }
 # rbx_reflection_database = { path = "../rbx-dom/rbx_reflection_database" }
 # rbx_xml = { path = "../rbx-dom/rbx_xml" }
 
-rbx_binary = "0.6.1"
-rbx_dom_weak = "2.1.0"
-rbx_reflection = "4.1.0"
-rbx_reflection_database = "0.2.1"
-rbx_xml = "0.12.1"
+rbx_binary = "0.6.4"
+rbx_dom_weak = "2.3.0"
+rbx_reflection = "4.2.0"
+rbx_reflection_database = "0.2.2"
+rbx_xml = "0.12.3"
 
-anyhow = "1.0.27"
-backtrace = "0.3"
-bincode = "1.2.1"
+anyhow = "1.0.44"
+backtrace = "0.3.61"
+bincode = "1.3.3"
 crossbeam-channel = "0.5.1"
-csv = "1.1.1"
+csv = "1.1.6"
 env_logger = "0.9.0"
-fs-err = "2.2.0"
-futures = "0.3.16"
-globset = "0.4.4"
+fs-err = "2.6.0"
+futures = "0.3.17"
+globset = "0.4.8"
 humantime = "2.1.0"
-hyper = { version = "0.14.11", features = ["server", "tcp", "http1"] }
-jod-thread = "0.1.0"
+hyper = { version = "0.14.13", features = ["server", "tcp", "http1"] }
+jod-thread = "0.1.2"
 lazy_static = "1.4.0"
-log = "0.4.8"
-maplit = "1.0.1"
-notify = "4.0.14"
+log = "0.4.14"
+maplit = "1.0.2"
+notify = "4.0.17"
 opener = "0.5.0"
-regex = "1.3.1"
-reqwest = "0.9.20"
+regex = "1.5.4"
+reqwest = "0.9.24"
 ritz = "0.1.0"
-rlua = "0.17.0"
+rlua = "0.17.1"
 roblox_install = "1.0.0"
-serde = { version = "1.0", features = ["derive", "rc"] }
-serde_json = "1.0"
-structopt = "0.3.5"
-termcolor = "1.0.5"
-thiserror = "1.0.11"
-tokio = { version = "1.9.0", features = ["rt", "rt-multi-thread"] }
-uuid = { version = "0.8.1", features = ["v4", "serde"] }
+serde = { version = "1.0.130", features = ["derive", "rc"] }
+serde_json = "1.0.68"
+structopt = "0.3.23"
+termcolor = "1.1.2"
+thiserror = "1.0.30"
+tokio = { version = "1.12.0", features = ["rt", "rt-multi-thread"] }
+uuid = { version = "0.8.2", features = ["v4", "serde"] }
 
 [target.'cfg(windows)'.dependencies]
 winreg = "0.9.0"
@@ -97,20 +93,20 @@ winreg = "0.9.0"
 [build-dependencies]
 memofs = { version = "0.2.0", path = "memofs" }
 
-embed-resource = "1.6"
-anyhow = "1.0.27"
-bincode = "1.2.1"
-fs-err = "2.3.0"
-maplit = "1.0.1"
+embed-resource = "1.6.4"
+anyhow = "1.0.44"
+bincode = "1.3.3"
+fs-err = "2.6.0"
+maplit = "1.0.2"
 
 [dev-dependencies]
 rojo-insta-ext = { path = "rojo-insta-ext" }
 
-criterion = "0.3"
-insta = { version = "1.3.0", features = ["redactions"] }
-lazy_static = "1.2"
+criterion = "0.3.5"
+insta = { version = "1.8.0", features = ["redactions"] }
+lazy_static = "1.4.0"
 paste = "1.0.5"
 pretty_assertions = "0.7.2"
-serde_yaml = "0.8.9"
-tempfile = "3.0"
-walkdir = "2.1"
+serde_yaml = "0.8.21"
+tempfile = "3.2.0"
+walkdir = "2.3.2"

plugin/rbx_dom_lua/EncodedValue.lua

@@ -388,6 +388,11 @@ types = {
 		end,
 	},
 
+	Tags = {
+		fromPod = identity,
+		toPod = identity,
+	},
+
 	Vector2 = {
 		fromPod = unpackDecoder(Vector2.new),
 

plugin/rbx_dom_lua/PropertyDescriptor.lua

@@ -20,7 +20,21 @@ local function set(container, key, value)
 end
 
 function PropertyDescriptor.fromRaw(data, className, propertyName)
+	local key, value = next(data.DataType)
+
 	return setmetatable({
+		-- The meanings of the key and value in DataType differ when the type of
+		-- the property is Enum. When the property is of type Enum, the key is
+		-- the name of the type:
+		--
+		-- { Enum = "<name of enum>" }
+		--
+		-- When the property is not of type Enum, the value is the name of the
+		-- type:
+		--
+		-- { Value = "<data type>" }
+		dataType = key == "Enum" and key or value,
+
 		scriptability = data.Scriptability,
 		className = className,
 		name = propertyName,
@@ -77,4 +91,4 @@ function PropertyDescriptor:write(instance, value)
 	end
 end
 
-return PropertyDescriptor
+return PropertyDescriptor

plugin/rbx_dom_lua/allValues.json

@@ -251,6 +251,16 @@
     },
     "ty": "String"
   },
+  "Tags": {
+    "value": {
+      "Tags": [
+        "foo",
+        "con'fusion?!",
+        "bar"
+      ]
+    },
+    "ty": "Tags"
+  },
   "UDim": {
     "value": {
       "UDim": [

plugin/rbx_dom_lua/customProperties.lua

@@ -6,12 +6,10 @@ local CollectionService = game:GetService("CollectionService")
 return {
 	Instance = {
 		Tags = {
-			read = function(instance, key)
-				local tagList = CollectionService:GetTags(instance)
-
-				return true, table.concat(tagList, "\0")
+			read = function(instance)
+				return true, CollectionService:GetTags(instance)
 			end,
-			write = function(instance, key, value)
+			write = function(instance, _, value)
 				local existingTags = CollectionService:GetTags(instance)
 
 				local unseenTags = {}
@@ -19,8 +17,7 @@ return {
 					unseenTags[tag] = true
 				end
 
-				local tagList = string.split(value, "\0")
-				for _, tag in ipairs(tagList) do
+				for _, tag in ipairs(value) do
 					unseenTags[tag] = nil
 					CollectionService:AddTag(instance, tag)
 				end
@@ -44,4 +41,4 @@ return {
 			end,
 		},
 	},
-}
+}

plugin/src/App/Components/Studio/StudioPluginAction.lua

@@ -0,0 +1,40 @@
+local Rojo = script:FindFirstAncestor("Rojo")
+local Plugin = Rojo.Plugin
+
+local Roact = require(Rojo.Roact)
+
+local Dictionary = require(Plugin.Dictionary)
+
+local StudioPluginContext = require(script.Parent.StudioPluginContext)
+
+local e = Roact.createElement
+
+local StudioPluginAction  = Roact.Component:extend("StudioPluginAction")
+
+function StudioPluginAction:init()
+	self.pluginAction = self.props.plugin:CreatePluginAction(
+		self.props.name, self.props.title, self.props.description, self.props.icon, self.props.bindable
+	)
+
+	self.pluginAction.Triggered:Connect(self.props.onTriggered)
+end
+
+function StudioPluginAction:render()
+	return nil
+end
+
+function StudioPluginAction:willUnmount()
+	self.pluginAction:Destroy()
+end
+
+local function StudioPluginActionWrapper(props)
+	return e(StudioPluginContext.Consumer, {
+		render = function(plugin)
+			return e(StudioPluginAction, Dictionary.merge(props, {
+				plugin = plugin,
+			}))
+		end,
+	})
+end
+
+return StudioPluginActionWrapper

plugin/src/App/Components/Studio/StudioToggleButton.lua

@@ -44,6 +44,10 @@ function StudioToggleButton:didUpdate(lastProps)
 		self.button.Enabled = self.props.enabled
 	end
 
+	if self.props.icon ~= lastProps.icon then
+		self.button.Icon = self.props.icon
+	end
+
 	if self.props.active ~= lastProps.active then
 		self.button:SetActive(self.props.active)
 	end
@@ -63,4 +67,4 @@ local function StudioToggleButtonWrapper(props)
 	})
 end
 
-return StudioToggleButtonWrapper
+return StudioToggleButtonWrapper

plugin/src/App/StatusPages/NotConnected.lua

@@ -24,7 +24,7 @@ local function AddressEntry(props)
 			layoutOrder = props.layoutOrder,
 		}, {
 			Host = e("TextBox", {
-				Text = "",
+				Text = props.host or "",
 				Font = Enum.Font.Code,
 				TextSize = 18,
 				TextColor3 = theme.AddressEntry.TextColor,
@@ -32,6 +32,7 @@ local function AddressEntry(props)
 				TextTransparency = props.transparency,
 				PlaceholderText = Config.defaultHost,
 				PlaceholderColor3 = theme.AddressEntry.PlaceholderColor,
+				ClearTextOnFocus = false,
 
 				Size = UDim2.new(1, -(HOST_OFFSET + DIVIDER_WIDTH + PORT_WIDTH), 1, 0),
 				Position = UDim2.new(0, HOST_OFFSET, 0, 0),
@@ -39,17 +40,22 @@ local function AddressEntry(props)
 				ClipsDescendants = true,
 				BackgroundTransparency = 1,
 
-				[Roact.Ref] = props.hostRef,
+				[Roact.Change.Text] = function(object)
+					if props.onHostChange ~= nil then
+						props.onHostChange(object.Text)
+					end
+				end
 			}),
 
 			Port = e("TextBox", {
-				Text = "",
+				Text = props.port or "",
 				Font = Enum.Font.Code,
 				TextSize = 18,
 				TextColor3 = theme.AddressEntry.TextColor,
 				TextTransparency = props.transparency,
 				PlaceholderText = Config.defaultPort,
 				PlaceholderColor3 = theme.AddressEntry.PlaceholderColor,
+				ClearTextOnFocus = false,
 
 				Size = UDim2.new(0, PORT_WIDTH, 1, 0),
 				Position = UDim2.new(1, 0, 0, 0),
@@ -58,12 +64,14 @@ local function AddressEntry(props)
 				ClipsDescendants = true,
 				BackgroundTransparency = 1,
 
-				[Roact.Ref] = props.portRef,
-
 				[Roact.Change.Text] = function(object)
 					local text = object.Text
 					text = text:gsub("%D", "")
 					object.Text = text
+
+					if props.onPortChange ~= nil then
+						props.onPortChange(text)
+					end
 				end,
 			}, {
 				Divider = e("Frame", {
@@ -80,11 +88,6 @@ end
 
 local NotConnectedPage = Roact.Component:extend("NotConnectedPage")
 
-function NotConnectedPage:init()
-	self.hostRef = Roact.createRef()
-	self.portRef = Roact.createRef()
-end
-
 function NotConnectedPage:render()
 	return Roact.createFragment({
 		Header = e(Header, {
@@ -93,8 +96,10 @@ function NotConnectedPage:render()
 		}),
 
 		AddressEntry = e(AddressEntry, {
-			hostRef = self.hostRef,
-			portRef = self.portRef,
+			host = self.props.host,
+			port = self.props.port,
+			onHostChange = self.props.onHostChange,
+			onPortChange = self.props.onPortChange,
 			transparency = self.props.transparency,
 			layoutOrder = 2,
 		}),
@@ -117,15 +122,7 @@ function NotConnectedPage:render()
 				style = "Solid",
 				transparency = self.props.transparency,
 				layoutOrder = 2,
-				onClick = function()
-					local hostText = self.hostRef.current.Text
-					local portText = self.portRef.current.Text
-
-					self.props.onConnect(
-						#hostText > 0 and hostText or Config.defaultHost,
-						#portText > 0 and portText or Config.defaultPort
-					)
-				end,
+				onClick = self.props.onConnect,
 			}),
 
 			Layout = e("UIListLayout", {

plugin/src/App/Theme.lua

@@ -34,7 +34,7 @@ end
 local BRAND_COLOR = hexColor(0xE13835)
 
 local lightTheme = strict("LightTheme", {
-	BackgroundColor = hexColor(0xF0F0F0),
+	BackgroundColor = hexColor(0xFFFFFF),
 	Button = {
 		Solid = {
 			ActionFillColor = hexColor(0xFFFFFF),
@@ -67,7 +67,7 @@ local lightTheme = strict("LightTheme", {
 			BackgroundColor = BRAND_COLOR,
 		},
 		Inactive = {
-			IconColor = hexColor(0xCACACA),
+			IconColor = hexColor(0xEEEEEE),
 			BorderColor = hexColor(0xAFAFAF),
 		},
 	},
@@ -77,11 +77,11 @@ local lightTheme = strict("LightTheme", {
 	},
 	BorderedContainer = {
 		BorderColor = hexColor(0xCBCBCB),
-		BackgroundColor = hexColor(0xE0E0E0),
+		BackgroundColor = hexColor(0xEEEEEE),
 	},
 	Spinner = {
 		ForegroundColor = BRAND_COLOR,
-		BackgroundColor = hexColor(0xE0E0E0),
+		BackgroundColor = hexColor(0xEEEEEE),
 	},
 	ConnectionDetails = {
 		ProjectNameColor = hexColor(0x00000),
@@ -108,7 +108,7 @@ local lightTheme = strict("LightTheme", {
 })
 
 local darkTheme = strict("DarkTheme", {
-	BackgroundColor = hexColor(0x272727),
+	BackgroundColor = hexColor(0x2E2E2E),
 	Button = {
 		Solid = {
 			ActionFillColor = hexColor(0xFFFFFF),
@@ -147,15 +147,15 @@ local darkTheme = strict("DarkTheme", {
 	},
 	AddressEntry = {
 		TextColor = hexColor(0xFFFFFF),
-		PlaceholderColor = hexColor(0x717171)
+		PlaceholderColor = hexColor(0x8B8B8B)
 	},
 	BorderedContainer = {
 		BorderColor = hexColor(0x535353),
-		BackgroundColor = hexColor(0x323232),
+		BackgroundColor = hexColor(0x2B2B2B),
 	},
 	Spinner = {
 		ForegroundColor = BRAND_COLOR,
-		BackgroundColor = hexColor(0x323232),
+		BackgroundColor = hexColor(0x2B2B2B),
 	},
 	ConnectionDetails = {
 		ProjectNameColor = hexColor(0xFFFFFF),
@@ -236,4 +236,4 @@ return {
 	StudioProvider = StudioProvider,
 	Consumer = Context.Consumer,
 	with = with,
-}
+}

plugin/src/App/init.lua

@@ -16,6 +16,7 @@ local Theme = require(script.Theme)
 local PluginSettings = require(script.PluginSettings)
 
 local Page = require(script.Page)
+local StudioPluginAction = require(script.Components.Studio.StudioPluginAction)
 local StudioToolbar = require(script.Components.Studio.StudioToolbar)
 local StudioToggleButton = require(script.Components.Studio.StudioToggleButton)
 local StudioPluginGui = require(script.Components.Studio.StudioPluginGui)
@@ -37,13 +38,34 @@ local App = Roact.Component:extend("App")
 function App:init()
 	preloadAssets()
 
+	self.host, self.setHost = Roact.createBinding("")
+	self.port, self.setPort = Roact.createBinding("")
+
 	self:setState({
 		appStatus = AppStatus.NotConnected,
 		guiEnabled = false,
+		toolbarIcon = Assets.Images.PluginButton,
 	})
 end
 
-function App:startSession(host, port, sessionOptions)
+function App:getHostAndPort()
+	local host = self.host:getValue()
+	local port = self.port:getValue()
+
+	local host = if #host > 0 then host else Config.defaultHost
+	local port = if #port > 0 then port else Config.defaultPort
+
+	return host, port
+end
+
+function App:startSession()
+	local host, port = self:getHostAndPort()
+
+	local sessionOptions = {
+		openScriptsExternally = self.props.settings:get("openScriptsExternally"),
+		twoWaySync = self.props.settings:get("twoWaySync"),
+	}
+
 	local baseUrl = ("http://%s:%s"):format(host, port)
 	local apiContext = ApiContext.new(baseUrl)
 
@@ -57,6 +79,7 @@ function App:startSession(host, port, sessionOptions)
 		if status == ServeSession.Status.Connecting then
 			self:setState({
 				appStatus = AppStatus.Connecting,
+				toolbarIcon = Assets.Images.PluginButton,
 			})
 		elseif status == ServeSession.Status.Connected then
 			local address = ("%s:%s"):format(host, port)
@@ -64,7 +87,10 @@ function App:startSession(host, port, sessionOptions)
 				appStatus = AppStatus.Connected,
 				projectName = details,
 				address = address,
+				toolbarIcon = Assets.Images.PluginButtonConnected,
 			})
+
+			Log.info("Connected to session '{}' at {}", details, address)
 		elseif status == ServeSession.Status.Disconnected then
 			self.serveSession = nil
 
@@ -76,11 +102,15 @@ function App:startSession(host, port, sessionOptions)
 				self:setState({
 					appStatus = AppStatus.Error,
 					errorMessage = tostring(details),
+					toolbarIcon = Assets.Images.PluginButtonWarning,
 				})
 			else
 				self:setState({
 					appStatus = AppStatus.NotConnected,
+					toolbarIcon = Assets.Images.PluginButton,
 				})
+
+				Log.info("Disconnected session")
 			end
 		end
 	end)
@@ -90,6 +120,22 @@ function App:startSession(host, port, sessionOptions)
 	self.serveSession = serveSession
 end
 
+function App:endSession()
+	if self.serveSession == nil then
+		return
+	end
+
+	Log.trace("Disconnecting session")
+
+	self.serveSession:stop()
+	self.serveSession = nil
+	self:setState({
+		appStatus = AppStatus.NotConnected,
+	})
+
+	Log.trace("Session terminated by user")
+end
+
 function App:render()
 	local pluginName = "Rojo " .. Version.display(Config.version)
 
@@ -136,22 +182,22 @@ function App:render()
 						})
 					end,
 				}, {
-					NotConnectedPage = PluginSettings.with(function(settings)
-						return createPageElement(AppStatus.NotConnected, {
-							onConnect = function(host, port)
-								self:startSession(host, port, {
-									openScriptsExternally = settings:get("openScriptsExternally"),
-									twoWaySync = settings:get("twoWaySync"),
-								})
-							end,
+					NotConnectedPage = createPageElement(AppStatus.NotConnected, {
+						host = self.host,
+						onHostChange = self.setHost,
+						port = self.port,
+						onPortChange = self.setPort,
 
-							onNavigateSettings = function()
-								self:setState({
-									appStatus = AppStatus.Settings,
-								})
-							end,
-						})
-					end),
+						onConnect = function()
+							self:startSession()
+						end,
+
+						onNavigateSettings = function()
+							self:setState({
+								appStatus = AppStatus.Settings,
+							})
+						end,
+					}),
 
 					Connecting = createPageElement(AppStatus.Connecting),
 
@@ -160,15 +206,7 @@ function App:render()
 						address = self.state.address,
 
 						onDisconnect = function()
-							Log.trace("Disconnecting session")
-
-							self.serveSession:stop()
-							self.serveSession = nil
-							self:setState({
-								appStatus = AppStatus.NotConnected,
-							})
-
-							Log.trace("Session terminated by user")
+							self:endSession()
 						end,
 					}),
 
@@ -186,6 +224,7 @@ function App:render()
 						onClose = function()
 							self:setState({
 								appStatus = AppStatus.NotConnected,
+								toolbarIcon = Assets.Images.PluginButton,
 							})
 						end,
 					}),
@@ -200,13 +239,54 @@ function App:render()
 					end),
 				}),
 
+				toggleAction = e(StudioPluginAction, {
+					name = "RojoConnection",
+					title = "Rojo: Connect/Disconnect",
+					description = "Toggles the server for a Rojo sync session",
+					icon = Assets.Images.PluginButton,
+					bindable = true,
+					onTriggered = function()
+						if self.serveSession == nil or self.serveSession:getStatus() == ServeSession.Status.NotStarted then
+							self:startSession()
+						elseif self.serveSession ~= nil and self.serveSession:getStatus() == ServeSession.Status.Connected then
+							self:endSession()
+						end
+					end,
+				}),
+
+				connectAction = e(StudioPluginAction, {
+					name = "RojoConnect",
+					title = "Rojo: Connect",
+					description = "Connects the server for a Rojo sync session",
+					icon = Assets.Images.PluginButton,
+					bindable = true,
+					onTriggered = function()
+						if self.serveSession == nil or self.serveSession:getStatus() == ServeSession.Status.NotStarted then
+							self:startSession()
+						end
+					end,
+				}),
+
+				disconnectAction = e(StudioPluginAction, {
+					name = "RojoDisconnect",
+					title = "Rojo: Disconnect",
+					description = "Disconnects the server for a Rojo sync session",
+					icon = Assets.Images.PluginButton,
+					bindable = true,
+					onTriggered = function()
+						if self.serveSession ~= nil and self.serveSession:getStatus() == ServeSession.Status.Connected then
+							self:endSession()
+						end
+					end,
+				}),
+
 				toolbar = e(StudioToolbar, {
 					name = pluginName,
 				}, {
 					button = e(StudioToggleButton, {
 						name = "Rojo",
 						tooltip = "Show or hide the Rojo panel",
-						icon = Assets.Images.PluginButton,
+						icon = self.state.toolbarIcon,
 						active = self.state.guiEnabled,
 						enabled = true,
 						onClick = function()
@@ -223,4 +303,15 @@ function App:render()
 	})
 end
 
-return App
+return function(props)
+	return e(PluginSettings.StudioProvider, {
+		plugin = props.plugin,
+	}, {
+		App = PluginSettings.with(function(settings)
+			local settingsProps = Dictionary.merge(props, {
+				settings = settings,
+			})
+			return e(App, settingsProps)
+		end),
+	})
+end

plugin/src/Assets.lua

@@ -18,6 +18,8 @@ local Assets = {
 	Images = {
 		Logo = "rbxassetid://5990772764",
 		PluginButton = "rbxassetid://3405341609",
+		PluginButtonConnected = "rbxassetid://9529783993",
+		PluginButtonWarning = "rbxassetid://9529784530",
 		Icons = {
 			Close = "rbxassetid://6012985953",
 			Back = "rbxassetid://6017213752",

plugin/src/ChangeBatcher/createPatchSet.lua

@@ -0,0 +1,40 @@
+--[[
+	Take an InstanceMap and a dictionary mapping instances to sets of property
+	names. Populate a patch with the encoded values of all the given properties
+	on all the given instances (or, if any changes set Parent to nil, removals
+	of instances) and return the patch.
+]]
+
+local Log = require(script.Parent.Parent.Parent.Log)
+
+local PatchSet = require(script.Parent.Parent.PatchSet)
+
+local encodePatchUpdate = require(script.Parent.encodePatchUpdate)
+
+return function(instanceMap, propertyChanges)
+	local patch = PatchSet.newEmpty()
+
+	for instance, properties in pairs(propertyChanges) do
+		local instanceId = instanceMap.fromInstances[instance]
+
+		if instanceId == nil then
+			Log.warn("Ignoring change for instance {:?} as it is unknown to Rojo", instance)
+			continue
+		end
+
+		if properties.Parent then
+			if instance.Parent == nil then
+				table.insert(patch.removed, instanceId)
+			else
+				Log.warn("Cannot sync non-nil Parent property changes yet")
+			end
+		else
+			local update = encodePatchUpdate(instance, instanceId, properties)
+			table.insert(patch.updated, update)
+		end
+
+		propertyChanges[instance] = nil
+	end
+
+	return patch
+end

plugin/src/ChangeBatcher/createPatchSet.spec.lua

@@ -0,0 +1,74 @@
+return function()
+	local PatchSet = require(script.Parent.Parent.PatchSet)
+	local InstanceMap = require(script.Parent.Parent.InstanceMap)
+
+	local createPatchSet = require(script.Parent.createPatchSet)
+
+	it("should return a patch", function()
+		local patch = createPatchSet(InstanceMap.new(), {})
+
+		assert(PatchSet.validate(patch))
+	end)
+
+	it("should contain updates for every instance with property changes", function()
+		local instanceMap = InstanceMap.new()
+
+		local part1 = Instance.new("Part")
+		instanceMap:insert("PART_1", part1)
+
+		local part2 = Instance.new("Part")
+		instanceMap:insert("PART_2", part2)
+
+		local changes = {
+			[part1] = {
+				Position = true,
+				Size = true,
+				Color = true,
+			},
+			[part2] = {
+				CFrame = true,
+				Velocity = true,
+				Transparency = true,
+			},
+		}
+
+		local patch = createPatchSet(instanceMap, changes)
+
+		expect(#patch.updated).to.equal(2)
+	end)
+
+	it("should not contain any updates for removed instances", function()
+		local instanceMap = InstanceMap.new()
+
+		local part1 = Instance.new("Part")
+		instanceMap:insert("PART_1", part1)
+
+		local changes = {
+			[part1] = {
+				Parent = true,
+				Position = true,
+				Size = true,
+			},
+		}
+
+		local patch = createPatchSet(instanceMap, changes)
+
+		expect(#patch.removed).to.equal(1)
+		expect(#patch.updated).to.equal(0)
+	end)
+
+	it("should remove instances from the property change table", function()
+		local instanceMap = InstanceMap.new()
+
+		local part1 = Instance.new("Part")
+		instanceMap:insert("PART_1", part1)
+
+		local changes = {
+			[part1] = {},
+		}
+
+		createPatchSet(instanceMap, changes)
+
+		expect(next(changes)).to.equal(nil)
+	end)
+end

plugin/src/ChangeBatcher/encodePatchUpdate.lua

@@ -0,0 +1,39 @@
+local Log = require(script.Parent.Parent.Parent.Log)
+local RbxDom = require(script.Parent.Parent.Parent.RbxDom)
+
+local encodeProperty = require(script.Parent.encodeProperty)
+
+return function(instance, instanceId, properties)
+	local update = {
+		id = instanceId,
+		changedProperties = {},
+	}
+
+	for propertyName in pairs(properties) do
+		if propertyName == "Name" then
+			update.changedName = instance.Name
+		else
+			local descriptor = RbxDom.findCanonicalPropertyDescriptor(instance.ClassName, propertyName)
+
+			if not descriptor then
+				Log.debug("Could not sync back property {:?}.{}", instance, propertyName)
+				continue
+			end
+
+			local encodeSuccess, encodeResult = encodeProperty(instance, propertyName, descriptor)
+
+			if not encodeSuccess then
+				Log.debug("Could not sync back property {:?}.{}: {}", instance, propertyName, encodeResult)
+				continue
+			end
+
+			update.changedProperties[propertyName] = encodeResult
+		end
+	end
+
+	if next(update.changedProperties) == nil and update.changedName == nil then
+		return nil
+	end
+
+	return update
+end

plugin/src/ChangeBatcher/encodePatchUpdate.spec.lua

@@ -0,0 +1,62 @@
+return function()
+	local encodePatchUpdate = require(script.Parent.encodePatchUpdate)
+
+	it("should return an update when there are property changes", function()
+		local part = Instance.new("Part")
+		local properties = {
+			CFrame = true,
+			Color = true,
+		}
+		local update = encodePatchUpdate(part, "PART", properties)
+
+		expect(update.id).to.equal("PART")
+		expect(update.changedProperties.CFrame).to.be.ok()
+		expect(update.changedProperties.Color).to.be.ok()
+	end)
+
+	it("should return nil when there are no property changes", function()
+		local part = Instance.new("Part")
+		local properties = {
+			NonExistentProperty = true,
+		}
+		local update = encodePatchUpdate(part, "PART", properties)
+
+		expect(update).to.equal(nil)
+	end)
+
+	it("should set changedName in the update when the instance's Name changes", function()
+		local part = Instance.new("Part")
+		local properties = {
+			Name = true,
+		}
+
+		part.Name = "We'reGettingToTheCoolPart"
+
+		local update = encodePatchUpdate(part, "PART", properties)
+
+		expect(update.changedName).to.equal("We'reGettingToTheCoolPart")
+	end)
+
+	it("should correctly encode property values", function()
+		local part = Instance.new("Part")
+		local properties = {
+			Position = true,
+			Color = true,
+		}
+
+		part.Position = Vector3.new(0, 100, 0)
+		part.Color = Color3.new(0.8, 0.2, 0.9)
+
+		local update = encodePatchUpdate(part, "PART", properties)
+		local position = update.changedProperties.Position
+		local color = update.changedProperties.Color
+
+		expect(position.Vector3[1]).to.equal(0)
+		expect(position.Vector3[2]).to.equal(100)
+		expect(position.Vector3[3]).to.equal(0)
+
+		expect(color.Color3[1]).to.be.near(0.8, 0.01)
+		expect(color.Color3[2]).to.be.near(0.2, 0.01)
+		expect(color.Color3[3]).to.be.near(0.9, 0.01)
+	end)
+end

plugin/src/ChangeBatcher/encodeProperty.lua

@@ -0,0 +1,21 @@
+local Log = require(script.Parent.Parent.Parent.Log)
+local RbxDom = require(script.Parent.Parent.Parent.RbxDom)
+
+return function(instance, propertyName, propertyDescriptor)
+	local readSuccess, readResult = propertyDescriptor:read(instance)
+
+	if not readSuccess then
+		Log.warn("Could not sync back property {:?}.{}: {}", instance, propertyName, readResult)
+		return false, nil
+	end
+
+	local dataType = propertyDescriptor.dataType
+	local encodeSuccess, encodeResult = RbxDom.EncodedValue.encode(readResult, dataType)
+
+	if not encodeSuccess then
+		Log.warn("Could not sync back property {:?}.{}: {}", instance, propertyName, encodeResult)
+		return false, nil
+	end
+
+	return true, encodeResult
+end

plugin/src/ChangeBatcher/init.lua

@@ -0,0 +1,81 @@
+--[[
+	The ChangeBatcher is responsible for collecting and dispatching changes made
+	to tracked instances during two-way sync.
+]]
+
+local RunService = game:GetService("RunService")
+
+local PatchSet = require(script.Parent.PatchSet)
+
+local createPatchSet = require(script.createPatchSet)
+
+local ChangeBatcher = {}
+ChangeBatcher.__index = ChangeBatcher
+
+local BATCH_INTERVAL = 0.2
+
+function ChangeBatcher.new(instanceMap, onChangesFlushed)
+	local self
+
+	local renderSteppedConnection = RunService.RenderStepped:Connect(function(dt)
+		self:__cycle(dt)
+	end)
+
+	self = setmetatable({
+		__accumulator = 0,
+		__renderSteppedConnection = renderSteppedConnection,
+		__instanceMap = instanceMap,
+		__onChangesFlushed = onChangesFlushed,
+		__pendingPropertyChanges = {},
+	}, ChangeBatcher)
+
+	return self
+end
+
+function ChangeBatcher:stop()
+	self.__renderSteppedConnection:Disconnect()
+	self.__pendingPropertyChanges = {}
+end
+
+function ChangeBatcher:add(instance, propertyName)
+	local properties = self.__pendingPropertyChanges[instance]
+
+	if not properties then
+		properties = {}
+		self.__pendingPropertyChanges[instance] = properties
+	end
+
+	properties[propertyName] = true
+end
+
+function ChangeBatcher:__cycle(dt)
+	self.__accumulator += dt
+
+	if self.__accumulator >= BATCH_INTERVAL then
+		self.__accumulator -= BATCH_INTERVAL
+
+		local patch = self:__flush()
+
+		if patch then
+			self.__onChangesFlushed(patch)
+		end
+	end
+
+	self.__instanceMap:unpauseAllInstances()
+end
+
+function ChangeBatcher:__flush()
+	if next(self.__pendingPropertyChanges) == nil then
+		return nil
+	end
+
+	local patch = createPatchSet(self.__instanceMap, self.__pendingPropertyChanges)
+
+	if PatchSet.isEmpty(patch) then
+		return nil
+	end
+
+	return patch
+end
+
+return ChangeBatcher

plugin/src/ChangeBatcher/init.spec.lua

@@ -0,0 +1,101 @@
+return function()
+	local ChangeBatcher = require(script.Parent)
+	local InstanceMap = require(script.Parent.Parent.InstanceMap)
+	local PatchSet = require(script.Parent.Parent.PatchSet)
+
+	local noop = function() end
+
+	describe("new", function()
+		it("should create a new ChangeBatcher", function()
+			local instanceMap = InstanceMap.new()
+			local changeBatcher = ChangeBatcher.new(instanceMap, noop)
+
+			expect(changeBatcher.__pendingPropertyChanges).to.be.a("table")
+			expect(next(changeBatcher.__pendingPropertyChanges)).to.equal(nil)
+			expect(changeBatcher.__onChangesFlushed).to.equal(noop)
+			expect(changeBatcher.__instanceMap).to.equal(instanceMap)
+			expect(typeof(changeBatcher.__renderSteppedConnection)).to.equal("RBXScriptConnection")
+		end)
+	end)
+
+	describe("stop", function()
+		it("should disconnect the RenderStepped connection", function()
+			local changeBatcher = ChangeBatcher.new(InstanceMap.new(), noop)
+
+			changeBatcher:stop()
+
+			expect(changeBatcher.__renderSteppedConnection.Connected).to.equal(false)
+		end)
+	end)
+
+	describe("add", function()
+		it("should add property changes to be considered for the current batch", function()
+			local instanceMap = InstanceMap.new()
+			local changeBatcher = ChangeBatcher.new(instanceMap, noop)
+			local part = Instance.new("Part")
+
+			instanceMap:insert("PART", part)
+			changeBatcher:add(part, "Name")
+
+			local properties = changeBatcher.__pendingPropertyChanges[part]
+
+			expect(properties).to.be.a("table")
+			expect(properties.Name).to.be.ok()
+
+			changeBatcher:add(part, "Position")
+			expect(properties.Position).to.be.ok()
+		end)
+	end)
+
+	describe("__cycle", function()
+		it("should immediately unpause any paused instances after each cycle", function()
+			local instanceMap = InstanceMap.new()
+			local changeBatcher = ChangeBatcher.new(instanceMap, noop)
+			local part = Instance.new("Part")
+
+			instanceMap.pausedUpdateInstances[part] = true
+
+			changeBatcher:__cycle(0)
+
+			expect(instanceMap.pausedUpdateInstances[part]).to.equal(nil)
+		end)
+	end)
+
+	describe("__flush", function()
+		it("should return nil when there are no changes to process", function()
+			local changeBatcher = ChangeBatcher.new(InstanceMap.new(), noop)
+			expect(changeBatcher:__flush()).to.equal(nil)
+		end)
+
+		it("should return a patch when there are changes to process and the resulting patch is non-empty", function()
+			local instanceMap = InstanceMap.new()
+			local changeBatcher = ChangeBatcher.new(instanceMap, noop)
+			local part = Instance.new("Part")
+
+			instanceMap:insert("PART", part)
+
+			changeBatcher.__pendingPropertyChanges[part] = {
+				Position = true,
+				Name = true,
+			}
+
+			local patch = changeBatcher:__flush()
+
+			assert(PatchSet.validate(patch))
+		end)
+
+		it("should return nil when there are changes to process and the resulting patch is empty", function()
+			local instanceMap = InstanceMap.new()
+			local changeBatcher = ChangeBatcher.new(instanceMap, noop)
+			local part = Instance.new("Part")
+
+			instanceMap:insert("PART", part)
+
+			changeBatcher.__pendingPropertyChanges[part] = {
+				NonExistentProperty = true,
+			}
+
+			expect(changeBatcher:__flush()).to.equal(nil)
+		end)
+	end)
+end

plugin/src/Config.lua

@@ -5,7 +5,7 @@ local isDevBuild = script.Parent.Parent:FindFirstChild("ROJO_DEV_BUILD") ~= nil
 return strict("Config", {
 	isDevBuild = isDevBuild,
 	codename = "Epiphany",
-	version = {7, 0, 0, "-rc.1"},
+	version = {7, 1, 0},
 	expectedServerVersionString = "7.0 or newer",
 	protocolVersion = 4,
 	defaultHost = "localhost",

plugin/src/InstanceMap.lua

@@ -1,3 +1,5 @@
+local RunService = game:GetService("RunService")
+
 local Log = require(script.Parent.Parent.Log)
 
 --[[
@@ -135,29 +137,31 @@ function InstanceMap:destroyId(id)
 end
 
 --[[
-	Pause updates for an instance momentarily and invoke a callback.
-
-	If the callback throws an error, InstanceMap will still be kept in a
-	consistent state.
+	Pause updates for an instance.
 ]]
-function InstanceMap:pauseInstance(instance, callback)
+function InstanceMap:pauseInstance(instance)
 	local id = self.fromInstances[instance]
 
-	-- If we don't know about this instance, ignore it and do not invoke the
-	-- callback.
+	-- If we don't know about this instance, ignore it.
 	if id == nil then
 		return
 	end
 
 	self.pausedUpdateInstances[instance] = true
-	local success, result = xpcall(callback, debug.traceback)
-	self.pausedUpdateInstances[instance] = false
+end
 
-	if success then
-		return result
-	else
-		error(result, 2)
-	end
+--[[
+	Unpause updates for an instance.
+]]
+function InstanceMap:unpauseInstance(instance)
+	self.pausedUpdateInstances[instance] = nil
+end
+
+--[[
+	Unpause updates for all instances.
+]]
+function InstanceMap:unpauseAllInstances()
+	table.clear(self.pausedUpdateInstances)
 end
 
 function InstanceMap:__connectSignals(instance)
@@ -200,6 +204,12 @@ function InstanceMap:__maybeFireInstanceChanged(instance, propertyName)
 		return
 	end
 
+	if RunService:IsRunning() then
+		-- We probably don't want to pick up property changes to save to the
+		-- filesystem in a running game.
+		return
+	end
+
 	self.onInstanceChanged(instance, propertyName)
 end
 
@@ -222,4 +232,4 @@ function InstanceMap:__disconnectSignals(instance)
 	end
 end
 
-return InstanceMap
+return InstanceMap

plugin/src/Reconciler/applyPatch.lua

@@ -63,7 +63,7 @@ local function applyPatch(instanceMap, patch)
 		local failedToReify = reify(instanceMap, patch.added, id, parentInstance)
 
 		if not PatchSet.isEmpty(failedToReify) then
-			Log.debug("Failed to reify as part of applying a patch: {}", failedToReify)
+			Log.debug("Failed to reify as part of applying a patch: {:#?}", failedToReify)
 			PatchSet.assign(unappliedPatch, failedToReify)
 		end
 	end
@@ -77,6 +77,10 @@ local function applyPatch(instanceMap, patch)
 			continue
 		end
 
+		-- Pause updates on this instance to avoid picking up our changes when
+		-- two-way sync is enabled.
+		instanceMap:pauseInstance(instance)
+
 		-- Track any part of this update that could not be applied.
 		local unappliedUpdate = {
 			id = update.id,
@@ -197,4 +201,4 @@ local function applyPatch(instanceMap, patch)
 	return unappliedPatch
 end
 
-return applyPatch
+return applyPatch

plugin/src/Reconciler/diff.lua

@@ -75,9 +75,13 @@ local function diff(instanceMap, virtualInstances, rootId)
 						changedProperties[propertyName] = virtualValue
 					end
 				else
-					-- virtualValue can be empty in certain cases, and this may print out nil to the user.
 					local propertyType = next(virtualValue)
-					Log.warn("Failed to decode property of type {}", propertyType)
+					Log.warn(
+						"Failed to decode property {}.{}. Encoded property was: {:#?}",
+						virtualInstance.ClassName,
+						propertyName,
+						virtualValue
+					)
 				end
 			else
 				local err = existingValueOrErr

plugin/src/Reconciler/getProperty.lua

@@ -40,6 +40,13 @@ local function getProperty(instance, propertyName)
 			})
 		end
 
+		if err.kind == RbxDom.Error.Kind.Roblox and err.extra:find("is not a valid member of") then
+			return false, Error.new(Error.UnknownProperty, {
+				className = instance.ClassName,
+				propertyName = propertyName,
+			})
+		end
+
 		return false, Error.new(Error.OtherPropertyError, {
 			className = instance.ClassName,
 			propertyName = propertyName,

plugin/src/Reconciler/reify.spec.lua

@@ -255,7 +255,7 @@ return function()
 				Name = "Child A",
 				Properties = {
 					Value = {
-						Ref = "Child B",
+						Ref = "CHILD_B",
 					},
 				},
 				Children = {},
@@ -287,7 +287,7 @@ return function()
 	-- constructed as part of a recursive call before the parent has totally
 	-- finished. Given deferred refs, this should not fail, but it is a good
 	-- case to test.
-	it("should apply properties containing refs to later siblings correctly", function()
+	it("should apply properties containing refs to later children correctly", function()
 		local virtualInstances = {
 			ROOT = {
 				ClassName = "ObjectValue",
@@ -344,4 +344,4 @@ return function()
 		expect(update.id).to.equal("ROOT")
 		expect(update.changedProperties.Value).to.equal(virtualInstances["ROOT"].Properties.Value)
 	end)
-end
+end

plugin/src/ServeSession.lua

@@ -5,6 +5,7 @@ local Log = require(script.Parent.Parent.Log)
 local Fmt = require(script.Parent.Parent.Fmt)
 local t = require(script.Parent.Parent.t)
 
+local ChangeBatcher = require(script.Parent.ChangeBatcher)
 local InstanceMap = require(script.Parent.InstanceMap)
 local PatchSet = require(script.Parent.PatchSet)
 local Reconciler = require(script.Parent.Reconciler)
@@ -56,10 +57,19 @@ function ServeSession.new(options)
 	-- Declare self ahead of time to capture it in a closure
 	local self
 	local function onInstanceChanged(instance, propertyName)
-		self:__onInstanceChanged(instance, propertyName)
+		if not self.__twoWaySync then
+			return
+		end
+
+		self.__changeBatcher:add(instance, propertyName)
+	end
+
+	local function onChangesFlushed(patch)
+		self.__apiContext:write(patch)
 	end
 
 	local instanceMap = InstanceMap.new(onInstanceChanged)
+	local changeBatcher = ChangeBatcher.new(instanceMap, onChangesFlushed)
 	local reconciler = Reconciler.new(instanceMap)
 
 	local connections = {}
@@ -82,6 +92,7 @@ function ServeSession.new(options)
 		__twoWaySync = options.twoWaySync,
 		__reconciler = reconciler,
 		__instanceMap = instanceMap,
+		__changeBatcher = changeBatcher,
 		__statusChangedCallback = nil,
 		__connections = connections,
 	}
@@ -102,6 +113,10 @@ function ServeSession:__fmtDebug(output)
 	output:write("}")
 end
 
+function ServeSession:getStatus()
+	return self.__status
+end
+
 function ServeSession:onStatusChanged(callback)
 	self.__statusChangedCallback = callback
 end
@@ -179,55 +194,6 @@ function ServeSession:__onActiveScriptChanged(activeScript)
 	self.__apiContext:open(scriptId)
 end
 
-function ServeSession:__onInstanceChanged(instance, propertyName)
-	if not self.__twoWaySync then
-		return
-	end
-
-	local instanceId = self.__instanceMap.fromInstances[instance]
-
-	if instanceId == nil then
-		Log.warn("Ignoring change for instance {:?} as it is unknown to Rojo", instance)
-		return
-	end
-
-	local remove = nil
-
-	local update = {
-		id = instanceId,
-		changedProperties = {},
-	}
-
-	if propertyName == "Name" then
-		update.changedName = instance.Name
-	elseif propertyName == "Parent" then
-		if instance.Parent == nil then
-			update = nil
-			remove = instanceId
-		else
-			Log.warn("Cannot sync non-nil Parent property changes yet")
-			return
-		end
-	else
-		local success, encoded = self.__reconciler:encodeApiValue(instance[propertyName])
-
-		if not success then
-			Log.warn("Could not sync back property {:?}.{}", instance, propertyName)
-			return
-		end
-
-		update.changedProperties[propertyName] = encoded
-	end
-
-	local patch = {
-		removed = {remove},
-		added = {},
-		updated = {update},
-	}
-
-	self.__apiContext:write(patch)
-end
-
 function ServeSession:__initialSync(rootInstanceId)
 	return self.__apiContext:read({ rootInstanceId })
 		:andThen(function(readResponseBody)
@@ -290,6 +256,7 @@ function ServeSession:__stopInternal(err)
 	self:__setStatus(Status.Disconnected, err)
 	self.__apiContext:disconnect()
 	self.__instanceMap:stop()
+	self.__changeBatcher:stop()
 
 	for _, connection in ipairs(self.__connections) do
 		connection:Disconnect()
@@ -305,4 +272,4 @@ function ServeSession:__setStatus(status, detail)
 	end
 end
 
-return ServeSession
+return ServeSession

plugin/test-place.project.json

@@ -9,7 +9,7 @@
       },
 
       "TestEZ": {
-        "$path": "modules/testez/lib"
+        "$path": "modules/testez"
       }
     },
 
@@ -25,4 +25,4 @@
       }
     }
   }
-}
+}

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

@@ -0,0 +1,24 @@
+---
+source: tests/tests/build.rs
+expression: contents
+
+---
+<roblox version="4">
+  <Item class="Folder" referent="0">
+    <Properties>
+      <string name="Name">optional</string>
+    </Properties>
+    <Item class="StringValue" referent="1">
+      <Properties>
+        <string name="Name">foo-optional</string>
+        <string name="Value">Hello, from foo.txt!</string>
+      </Properties>
+    </Item>
+    <Item class="StringValue" referent="2">
+      <Properties>
+        <string name="Name">foo-required</string>
+        <string name="Value">Hello, from foo.txt!</string>
+      </Properties>
+    </Item>
+  </Item>
+</roblox>

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

@@ -0,0 +1,17 @@
+---
+source: tests/tests/build.rs
+expression: contents
+
+---
+<roblox version="4">
+  <Item class="Folder" referent="0">
+    <Properties>
+      <string name="Name">root</string>
+    </Properties>
+    <Item class="Folder" referent="1">
+      <Properties>
+        <string name="Name">folder</string>
+      </Properties>
+    </Item>
+  </Item>
+</roblox>

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

@@ -0,0 +1,22 @@
+---
+source: tests/tests/build.rs
+expression: contents
+
+---
+<roblox version="4">
+  <Item class="Folder" referent="0">
+    <Properties>
+      <string name="Name">root</string>
+    </Properties>
+    <Item class="Folder" referent="1">
+      <Properties>
+        <string name="Name">folder</string>
+      </Properties>
+      <Item class="Folder" referent="2">
+        <Properties>
+          <string name="Name">child-projectname</string>
+        </Properties>
+      </Item>
+    </Item>
+  </Item>
+</roblox>

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

@@ -0,0 +1,12 @@
+---
+source: tests/tests/build.rs
+expression: contents
+
+---
+<roblox version="4">
+  <Item class="Folder" referent="0">
+    <Properties>
+      <string name="Name">root</string>
+    </Properties>
+  </Item>
+</roblox>

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

@@ -1,6 +1,7 @@
 ---
 source: tests/tests/build.rs
 expression: contents
+
 ---
 <roblox version="4">
   <Item class="Folder" referent="0">
@@ -25,14 +26,12 @@ expression: contents
           <R22>1</R22>
         </CoordinateFrame>
         <Ref name="PrimaryPart">null</Ref>
-        <BinaryString name="Tags">
-        </BinaryString>
+        <BinaryString name="Tags"></BinaryString>
       </Properties>
       <Item class="StringValue" referent="2">
         <Properties>
           <string name="Name">Cool StringValue</string>
-          <BinaryString name="Tags">
-          </BinaryString>
+          <BinaryString name="Tags"></BinaryString>
           <string name="Value">Did you know that BaseValue.Changed is different than Instance.Changed?</string>
         </Properties>
       </Item>

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

@@ -1,27 +1,25 @@
 ---
 source: tests/tests/build.rs
 expression: contents
+
 ---
 <roblox version="4">
   <Item class="Folder" referent="0">
     <Properties>
       <string name="Name">rbxmx_ref</string>
-      <BinaryString name="Tags">
-      </BinaryString>
+      <BinaryString name="Tags"></BinaryString>
     </Properties>
     <Item class="StringValue" referent="1">
       <Properties>
         <string name="Name">Target</string>
-        <BinaryString name="Tags">
-        </BinaryString>
+        <BinaryString name="Tags"></BinaryString>
         <string name="Value">Pointed to by ObjectValue</string>
       </Properties>
     </Item>
     <Item class="ObjectValue" referent="2">
       <Properties>
         <string name="Name">Pointer</string>
-        <BinaryString name="Tags">
-        </BinaryString>
+        <BinaryString name="Tags"></BinaryString>
         <Ref name="Value">1</Ref>
       </Properties>
     </Item>

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

@@ -32,6 +32,20 @@ expression: contents
       <Item class="Part" referent="4">
         <Properties>
           <string name="Name">Color</string>
+          <CoordinateFrame name="CFrame">
+            <X>1</X>
+            <Y>2</Y>
+            <Z>3</Z>
+            <R00>0</R00>
+            <R01>1</R01>
+            <R02>0</R02>
+            <R10>0</R10>
+            <R11>0</R11>
+            <R12>1</R12>
+            <R20>1</R20>
+            <R21>0</R21>
+            <R22>0</R22>
+          </CoordinateFrame>
           <Color3uint8 name="Color3uint8">8404992</Color3uint8>
         </Properties>
       </Item>

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

@@ -0,0 +1,230 @@
+---
+source: tests/tests/build.rs
+expression: contents
+
+---
+<roblox version="4">
+  <Item class="Folder" referent="0">
+    <Properties>
+      <string name="Name">weldconstraint</string>
+      <BinaryString name="AttributesSerialize">
+      </BinaryString>
+      <int64 name="SourceAssetId">-1</int64>
+      <BinaryString name="Tags"></BinaryString>
+    </Properties>
+    <Item class="Part" referent="1">
+      <Properties>
+        <string name="Name">A</string>
+        <bool name="Anchored">false</bool>
+        <BinaryString name="AttributesSerialize">
+        </BinaryString>
+        <float name="BackParamA">-0.5</float>
+        <float name="BackParamB">0.5</float>
+        <token name="BackSurface">0</token>
+        <token name="BackSurfaceInput">0</token>
+        <float name="BottomParamA">-0.5</float>
+        <float name="BottomParamB">0.5</float>
+        <token name="BottomSurface">0</token>
+        <token name="BottomSurfaceInput">0</token>
+        <CoordinateFrame name="CFrame">
+          <X>-14</X>
+          <Y>0.5</Y>
+          <Z>-5</Z>
+          <R00>1</R00>
+          <R01>0</R01>
+          <R02>0</R02>
+          <R10>0</R10>
+          <R11>1</R11>
+          <R12>0</R12>
+          <R20>0</R20>
+          <R21>0</R21>
+          <R22>1</R22>
+        </CoordinateFrame>
+        <bool name="CanCollide">true</bool>
+        <bool name="CanQuery">true</bool>
+        <bool name="CanTouch">true</bool>
+        <bool name="CastShadow">true</bool>
+        <int name="CollisionGroupId">0</int>
+        <Color3uint8 name="Color3uint8">10724005</Color3uint8>
+        <PhysicalProperties name="CustomPhysicalProperties">
+          <CustomPhysics>false</CustomPhysics>
+        </PhysicalProperties>
+        <token name="formFactorRaw">1</token>
+        <float name="FrontParamA">-0.5</float>
+        <float name="FrontParamB">0.5</float>
+        <token name="FrontSurface">0</token>
+        <token name="FrontSurfaceInput">0</token>
+        <float name="LeftParamA">-0.5</float>
+        <float name="LeftParamB">0.5</float>
+        <token name="LeftSurface">0</token>
+        <token name="LeftSurfaceInput">0</token>
+        <bool name="Locked">false</bool>
+        <bool name="Massless">false</bool>
+        <token name="Material">256</token>
+        <CoordinateFrame name="PivotOffset">
+          <X>0</X>
+          <Y>0</Y>
+          <Z>0</Z>
+          <R00>1</R00>
+          <R01>0</R01>
+          <R02>0</R02>
+          <R10>0</R10>
+          <R11>1</R11>
+          <R12>0</R12>
+          <R20>0</R20>
+          <R21>0</R21>
+          <R22>1</R22>
+        </CoordinateFrame>
+        <float name="Reflectance">0</float>
+        <float name="RightParamA">-0.5</float>
+        <float name="RightParamB">0.5</float>
+        <token name="RightSurface">0</token>
+        <token name="RightSurfaceInput">0</token>
+        <int name="RootPriority">0</int>
+        <Vector3 name="RotVelocity">
+          <X>0</X>
+          <Y>0</Y>
+          <Z>0</Z>
+        </Vector3>
+        <token name="shape">1</token>
+        <Vector3 name="size">
+          <X>4</X>
+          <Y>1</Y>
+          <Z>2</Z>
+        </Vector3>
+        <int64 name="SourceAssetId">-1</int64>
+        <BinaryString name="Tags"></BinaryString>
+        <float name="TopParamA">-0.5</float>
+        <float name="TopParamB">0.5</float>
+        <token name="TopSurface">0</token>
+        <token name="TopSurfaceInput">0</token>
+        <float name="Transparency">0</float>
+        <Vector3 name="Velocity">
+          <X>0</X>
+          <Y>0</Y>
+          <Z>0</Z>
+        </Vector3>
+      </Properties>
+      <Item class="WeldConstraint" referent="2">
+        <Properties>
+          <string name="Name">WeldConstraint</string>
+          <BinaryString name="AttributesSerialize">
+          </BinaryString>
+          <CoordinateFrame name="CFrame0">
+            <X>7</X>
+            <Y>0.000001013279</Y>
+            <Z>-3</Z>
+            <R00>1</R00>
+            <R01>0</R01>
+            <R02>0</R02>
+            <R10>0</R10>
+            <R11>1</R11>
+            <R12>0</R12>
+            <R20>0</R20>
+            <R21>0</R21>
+            <R22>1</R22>
+          </CoordinateFrame>
+          <Ref name="Part0Internal">1</Ref>
+          <Ref name="Part1Internal">3</Ref>
+          <int64 name="SourceAssetId">-1</int64>
+          <int name="State">3</int>
+          <BinaryString name="Tags"></BinaryString>
+        </Properties>
+      </Item>
+    </Item>
+    <Item class="Part" referent="3">
+      <Properties>
+        <string name="Name">B</string>
+        <bool name="Anchored">false</bool>
+        <BinaryString name="AttributesSerialize">
+        </BinaryString>
+        <float name="BackParamA">-0.5</float>
+        <float name="BackParamB">0.5</float>
+        <token name="BackSurface">0</token>
+        <token name="BackSurfaceInput">0</token>
+        <float name="BottomParamA">-0.5</float>
+        <float name="BottomParamB">0.5</float>
+        <token name="BottomSurface">0</token>
+        <token name="BottomSurfaceInput">0</token>
+        <CoordinateFrame name="CFrame">
+          <X>-7</X>
+          <Y>0.500001</Y>
+          <Z>-8</Z>
+          <R00>1</R00>
+          <R01>0</R01>
+          <R02>0</R02>
+          <R10>0</R10>
+          <R11>1</R11>
+          <R12>0</R12>
+          <R20>0</R20>
+          <R21>0</R21>
+          <R22>1</R22>
+        </CoordinateFrame>
+        <bool name="CanCollide">true</bool>
+        <bool name="CanQuery">true</bool>
+        <bool name="CanTouch">true</bool>
+        <bool name="CastShadow">true</bool>
+        <int name="CollisionGroupId">0</int>
+        <Color3uint8 name="Color3uint8">10724005</Color3uint8>
+        <PhysicalProperties name="CustomPhysicalProperties">
+          <CustomPhysics>false</CustomPhysics>
+        </PhysicalProperties>
+        <token name="formFactorRaw">1</token>
+        <float name="FrontParamA">-0.5</float>
+        <float name="FrontParamB">0.5</float>
+        <token name="FrontSurface">0</token>
+        <token name="FrontSurfaceInput">0</token>
+        <float name="LeftParamA">-0.5</float>
+        <float name="LeftParamB">0.5</float>
+        <token name="LeftSurface">0</token>
+        <token name="LeftSurfaceInput">0</token>
+        <bool name="Locked">false</bool>
+        <bool name="Massless">false</bool>
+        <token name="Material">256</token>
+        <CoordinateFrame name="PivotOffset">
+          <X>0</X>
+          <Y>0</Y>
+          <Z>0</Z>
+          <R00>1</R00>
+          <R01>0</R01>
+          <R02>0</R02>
+          <R10>0</R10>
+          <R11>1</R11>
+          <R12>0</R12>
+          <R20>0</R20>
+          <R21>0</R21>
+          <R22>1</R22>
+        </CoordinateFrame>
+        <float name="Reflectance">0</float>
+        <float name="RightParamA">-0.5</float>
+        <float name="RightParamB">0.5</float>
+        <token name="RightSurface">0</token>
+        <token name="RightSurfaceInput">0</token>
+        <int name="RootPriority">0</int>
+        <Vector3 name="RotVelocity">
+          <X>0</X>
+          <Y>0</Y>
+          <Z>0</Z>
+        </Vector3>
+        <token name="shape">1</token>
+        <Vector3 name="size">
+          <X>4</X>
+          <Y>1</Y>
+          <Z>2</Z>
+        </Vector3>
+        <int64 name="SourceAssetId">-1</int64>
+        <BinaryString name="Tags"></BinaryString>
+        <float name="TopParamA">-0.5</float>
+        <float name="TopParamB">0.5</float>
+        <token name="TopSurface">0</token>
+        <token name="TopSurfaceInput">0</token>
+        <float name="Transparency">0</float>
+        <Vector3 name="Velocity">
+          <X>0</X>
+          <Y>0</Y>
+          <Z>0</Z>
+        </Vector3>
+      </Properties>
+    </Item>
+  </Item>
+</roblox>

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

@@ -0,0 +1,15 @@
+{
+  "name": "optional",
+  "tree": {
+    "$className": "Folder",
+    "foo-required": {
+      "$path": "foo.txt"
+    },
+    "foo-optional":{
+      "$path": { "optional": "foo.txt" }
+    },
+    "bar-optional":{
+      "$path": { "optional": "bar.txt" }
+    }
+  }
+}

rojo-test/build-tests/optional/foo.txt

@@ -0,0 +1 @@
+Hello, from foo.txt!

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

@@ -0,0 +1,9 @@
+{
+	"name": "root",
+	"tree": {
+		"$className": "Folder",
+		"folder": {
+			"$path": "folder"
+		}
+	}
+}

rojo-test/build-tests/project_composed_default/folder/default.project.json

@@ -0,0 +1,6 @@
+{
+	"name": "child-projectname",
+	"tree": {
+		"$className": "Folder"
+	}
+}

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

@@ -0,0 +1,9 @@
+{
+	"name": "root",
+	"tree": {
+		"$className": "Folder",
+		"folder": {
+			"$path": "folder"
+		}
+	}
+}

rojo-test/build-tests/project_composed_file/folder/child-filename.project.json

@@ -0,0 +1,6 @@
+{
+	"name": "child-projectname",
+	"tree": {
+		"$className": "Folder"
+	}
+}

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

@@ -0,0 +1,6 @@
+{
+	"name": "root",
+	"tree": {
+		"$className": "Folder"
+	}
+}

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

@@ -14,7 +14,13 @@
       "Color": {
         "$className": "Part",
         "$properties": {
-          "Color": [0.5, 0.25, 0]
+          "Color": [0.5, 0.25, 0],
+          "CFrame": [
+            1, 2, 3,
+            0, 1, 0,
+            0, 0, 1,
+            1, 0, 0
+          ]
         }
       },
 

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

@@ -0,0 +1,6 @@
+{
+  "name": "weldconstraint",
+  "tree": {
+    "$path": "two-parts-welded.rbxmx"
+  }
+}

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

@@ -0,0 +1,14 @@
+---
+source: tests/tests/serve.rs
+expression: redactions.redacted_yaml(info)
+
+---
+expectedPlaceIds: ~
+gameId: ~
+placeId: ~
+projectName: optional
+protocolVersion: 4
+rootInstanceId: id-2
+serverVersion: "[server-version]"
+sessionId: id-1
+

rojo-test/serve-test-snapshots/end_to_end__tests__serve__add_optional_folder_all-2.snap

@@ -0,0 +1,62 @@
+---
+source: tests/tests/serve.rs
+expression: "read_response.intern_and_redact(&mut redactions, root_id)"
+
+---
+instances:
+  id-2:
+    Children:
+      - id-3
+    ClassName: Folder
+    Id: id-2
+    Metadata:
+      ignoreUnknownInstances: true
+    Name: optional
+    Parent: "00000000000000000000000000000000"
+    Properties: {}
+  id-3:
+    Children:
+      - id-4
+      - id-5
+    ClassName: Folder
+    Id: id-3
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: src
+    Parent: id-2
+    Properties: {}
+  id-4:
+    Children: []
+    ClassName: StringValue
+    Id: id-4
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: foo
+    Parent: id-3
+    Properties:
+      Value:
+        String: "Hello, from foo.txt!"
+  id-5:
+    Children:
+      - id-6
+    ClassName: Folder
+    Id: id-5
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: node_modules
+    Parent: id-3
+    Properties: {}
+  id-6:
+    Children: []
+    ClassName: StringValue
+    Id: id-6
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: bar
+    Parent: id-5
+    Properties:
+      Value:
+        String: Hello from bar.txt
+messageCursor: 2
+sessionId: id-1
+

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

@@ -0,0 +1,40 @@
+---
+source: tests/tests/serve.rs
+expression: "read_response.intern_and_redact(&mut redactions, root_id)"
+
+---
+instances:
+  id-2:
+    Children:
+      - id-3
+    ClassName: Folder
+    Id: id-2
+    Metadata:
+      ignoreUnknownInstances: true
+    Name: optional
+    Parent: "00000000000000000000000000000000"
+    Properties: {}
+  id-3:
+    Children:
+      - id-4
+    ClassName: Folder
+    Id: id-3
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: src
+    Parent: id-2
+    Properties: {}
+  id-4:
+    Children: []
+    ClassName: StringValue
+    Id: id-4
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: foo
+    Parent: id-3
+    Properties:
+      Value:
+        String: "Hello, from foo.txt!"
+messageCursor: 0
+sessionId: id-1
+

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

@@ -0,0 +1,36 @@
+---
+source: tests/tests/serve.rs
+expression: "subscribe_response.intern_and_redact(&mut redactions, ())"
+
+---
+messageCursor: 2
+messages:
+  - added:
+      id-5:
+        Children:
+          - id-6
+        ClassName: Folder
+        Id: id-5
+        Metadata:
+          ignoreUnknownInstances: false
+        Name: node_modules
+        Parent: id-3
+        Properties: {}
+      id-6:
+        Children: []
+        ClassName: StringValue
+        Id: id-6
+        Metadata:
+          ignoreUnknownInstances: false
+        Name: bar
+        Parent: id-5
+        Properties:
+          Value:
+            String: Hello from bar.txt
+    removed: []
+    updated: []
+  - added: {}
+    removed: []
+    updated: []
+sessionId: id-1
+

rojo-test/serve-tests/add_optional_folder/default.project.json

@@ -0,0 +1,9 @@
+{
+  "name": "optional",
+  "tree": {
+    "$className": "Folder",
+    "create-later": {
+      "$path": { "optional": "create-later" }
+    }
+  }
+}

selene.toml

@@ -1,4 +1,4 @@
-std = "roblox"
+std = "roblox+testez"
 
 [config]
 unused_variable = { allow_unused_self = true }

src/change_processor.rs

@@ -284,22 +284,14 @@ fn compute_and_apply_changes(tree: &mut RojoTree, vfs: &Vfs, id: Ref) -> Option<
                 // that path and use it as the source for our patch.
 
                 let snapshot = match snapshot_from_vfs(&metadata.context, &vfs, &path) {
-                    Ok(Some(snapshot)) => snapshot,
-                    Ok(None) => {
-                        log::error!(
-                            "Snapshot did not return an instance from path {}",
-                            path.display()
-                        );
-                        log::error!("This may be a bug!");
-                        return None;
-                    }
+                    Ok(snapshot) => snapshot,
                     Err(err) => {
                         log::error!("Snapshot error: {:?}", err);
                         return None;
                     }
                 };
 
-                let patch_set = compute_patch_set(&snapshot, &tree, id);
+                let patch_set = compute_patch_set(snapshot.as_ref(), &tree, id);
                 apply_patch_set(tree, patch_set)
             }
             Ok(None) => {
@@ -335,19 +327,14 @@ fn compute_and_apply_changes(tree: &mut RojoTree, vfs: &Vfs, id: Ref) -> Option<
             );
 
             let snapshot = match snapshot_result {
-                Ok(Some(snapshot)) => snapshot,
-                Ok(None) => {
-                    log::error!("Snapshot did not return an instance from a project node.");
-                    log::error!("This is a bug!");
-                    return None;
-                }
+                Ok(snapshot) => snapshot,
                 Err(err) => {
                     log::error!("{:?}", err);
                     return None;
                 }
             };
 
-            let patch_set = compute_patch_set(&snapshot, &tree, id);
+            let patch_set = compute_patch_set(snapshot.as_ref(), &tree, id);
             apply_patch_set(tree, patch_set)
         }
     };

src/cli/mod.rs

@@ -6,6 +6,7 @@ mod fmt_project;
 mod init;
 mod plugin;
 mod serve;
+mod sourcemap;
 mod upload;
 
 use std::{borrow::Cow, env, path::Path, str::FromStr};
@@ -19,6 +20,7 @@ pub use self::fmt_project::FmtProjectCommand;
 pub use self::init::{InitCommand, InitKind};
 pub use self::plugin::{PluginCommand, PluginSubcommand};
 pub use self::serve::ServeCommand;
+pub use self::sourcemap::SourcemapCommand;
 pub use self::upload::UploadCommand;
 
 /// Command line options that Rojo accepts, defined using the structopt crate.
@@ -40,6 +42,7 @@ impl Options {
             Subcommand::Serve(subcommand) => subcommand.run(self.global),
             Subcommand::Build(subcommand) => subcommand.run(),
             Subcommand::Upload(subcommand) => subcommand.run(),
+            Subcommand::Sourcemap(subcommand) => subcommand.run(),
             Subcommand::FmtProject(subcommand) => subcommand.run(),
             Subcommand::Doc(subcommand) => subcommand.run(),
             Subcommand::Plugin(subcommand) => subcommand.run(),
@@ -112,6 +115,7 @@ pub enum Subcommand {
     Serve(ServeCommand),
     Build(BuildCommand),
     Upload(UploadCommand),
+    Sourcemap(SourcemapCommand),
     FmtProject(FmtProjectCommand),
     Doc(DocCommand),
     Plugin(PluginCommand),

src/cli/serve.rs

@@ -41,7 +41,10 @@ impl ServeCommand {
 
         let session = Arc::new(ServeSession::new(vfs, &project_path)?);
 
-        let ip = self.address.unwrap_or(DEFAULT_BIND_ADDRESS.into());
+        let ip = self
+            .address
+            .or_else(|| session.serve_address())
+            .unwrap_or(DEFAULT_BIND_ADDRESS.into());
 
         let port = self
             .port

src/cli/sourcemap.rs

@@ -0,0 +1,139 @@
+use std::{
+    io::{BufWriter, Write},
+    path::{Path, PathBuf},
+};
+
+use fs_err::File;
+use memofs::Vfs;
+use rbx_dom_weak::types::Ref;
+use serde::Serialize;
+use structopt::StructOpt;
+
+use crate::{
+    serve_session::ServeSession,
+    snapshot::{InstanceWithMeta, RojoTree},
+};
+
+use super::resolve_path;
+
+const PATH_STRIP_FAILED_ERR: &str = "Failed to create relative paths for project file!";
+
+/// Representation of a node in the generated sourcemap tree.
+#[derive(Serialize)]
+#[serde(rename_all = "camelCase")]
+struct SourcemapNode {
+    name: String,
+    class_name: String,
+
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    file_paths: Vec<PathBuf>,
+
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    children: Vec<SourcemapNode>,
+}
+
+/// Generates a sourcemap file from the Rojo project.
+#[derive(Debug, StructOpt)]
+pub struct SourcemapCommand {
+    /// Path to the project to use for the sourcemap. Defaults to the current
+    /// directory.
+    #[structopt(default_value = "")]
+    pub project: PathBuf,
+
+    /// Where to output the sourcemap. Omit this to use stdout instead of
+    /// writing to a file.
+    ///
+    /// Should end in .json.
+    #[structopt(long, short)]
+    pub output: Option<PathBuf>,
+
+    /// If non-script files should be included or not. Defaults to false.
+    #[structopt(long)]
+    pub include_non_scripts: bool,
+}
+
+impl SourcemapCommand {
+    pub fn run(self) -> anyhow::Result<()> {
+        let project_path = resolve_path(&self.project);
+
+        let mut project_dir = project_path.to_path_buf();
+        project_dir.pop();
+
+        log::trace!("Constructing in-memory filesystem");
+        let vfs = Vfs::new_default();
+
+        let session = ServeSession::new(vfs, &project_path)?;
+        let tree = session.tree();
+
+        let filter = if self.include_non_scripts {
+            filter_nothing
+        } else {
+            filter_non_scripts
+        };
+
+        let root_node = recurse_create_node(&tree, tree.get_root_id(), &project_dir, filter);
+
+        if let Some(output_path) = self.output {
+            let mut file = BufWriter::new(File::create(&output_path)?);
+            serde_json::to_writer(&mut file, &root_node)?;
+            file.flush()?;
+
+            println!("Created sourcemap at {}", output_path.display());
+        } else {
+            let output = serde_json::to_string(&root_node)?;
+            println!("{}", output);
+        }
+
+        Ok(())
+    }
+}
+
+fn filter_nothing(_instance: &InstanceWithMeta) -> bool {
+    true
+}
+
+fn filter_non_scripts(instance: &InstanceWithMeta) -> bool {
+    match instance.class_name() {
+        "Script" | "LocalScript" | "ModuleScript" => true,
+        _ => false,
+    }
+}
+
+fn recurse_create_node(
+    tree: &RojoTree,
+    referent: Ref,
+    project_dir: &Path,
+    filter: fn(&InstanceWithMeta) -> bool,
+) -> Option<SourcemapNode> {
+    let instance = tree.get_instance(referent).expect("instance did not exist");
+
+    let mut children = Vec::new();
+    for &child_id in instance.children() {
+        if let Some(child_node) = recurse_create_node(tree, child_id, &project_dir, filter) {
+            children.push(child_node);
+        }
+    }
+
+    // If this object has no children and doesn't pass the filter, it doesn't
+    // contain any information we're looking for.
+    if children.is_empty() && !filter(&instance) {
+        return None;
+    }
+
+    let file_paths = instance
+        .metadata()
+        .relevant_paths
+        .iter()
+        // Not all paths listed as relevant are guaranteed to exist.
+        .filter(|path| path.is_file())
+        .map(|path| path.strip_prefix(project_dir).expect(PATH_STRIP_FAILED_ERR))
+        .map(|path| path.to_path_buf())
+        .collect();
+
+    Some(SourcemapNode {
+        name: instance.name().to_string(),
+        class_name: instance.class_name().to_string(),
+        file_paths,
+        children,
+    })
+}

src/cli/upload.rs

@@ -24,6 +24,14 @@ pub struct UploadCommand {
     #[structopt(long)]
     pub cookie: Option<String>,
 
+    /// API key obtained from create.roblox.com/credentials. Rojo will use the Open Cloud API when this is provided. Only supports uploading to a place.
+    #[structopt(long = "api_key")]
+    pub api_key: Option<String>,
+
+    /// The Universe ID of the given place. Required when using the Open Cloud API.
+    #[structopt(long = "universe_id")]
+    pub universe_id: Option<u64>,
+
     /// Asset ID to upload to.
     #[structopt(long = "asset_id")]
     pub asset_id: u64,
@@ -33,10 +41,6 @@ impl UploadCommand {
     pub fn run(self) -> Result<(), anyhow::Error> {
         let project_path = resolve_path(&self.project);
 
-        let cookie = self.cookie.or_else(get_auth_cookie).context(
-            "Rojo could not find your Roblox auth cookie. Please pass one via --cookie.",
-        )?;
-
         let vfs = Vfs::new_default();
 
         let session = ServeSession::new(vfs, project_path)?;
@@ -54,7 +58,36 @@ impl UploadCommand {
 
         log::trace!("Encoding binary model");
         rbx_binary::to_writer(&mut buffer, tree.inner(), &encode_ids)?;
-        do_upload(buffer, self.asset_id, &cookie)
+
+        match (self.cookie, self.api_key, self.universe_id) {
+            (cookie, None, universe) => {
+                // using legacy. notify if universe is provided.
+                if universe.is_some() {
+                    log::warn!(
+                        "--universe_id was provided but is ignored when using legacy upload"
+                    );
+                }
+
+                let cookie = cookie.or_else(get_auth_cookie).context(
+                    "Rojo could not find your Roblox auth cookie. Please pass one via --cookie.",
+                )?;
+                do_upload(buffer, self.asset_id, &cookie)
+            }
+
+            (cookie, Some(api_key), Some(universe_id)) => {
+                // using open cloud. notify if cookie is provided.
+                if cookie.is_some() {
+                    log::warn!("--cookie was provided but is ignored when using Open Cloud API");
+                }
+
+                do_upload_open_cloud(buffer, universe_id, self.asset_id, &api_key)
+            }
+
+            (_, Some(_), None) => {
+                // API key is provided, universe id is not.
+                bail!("--universe_id must be provided to use the Open Cloud API");
+            }
+        }
     }
 }
 
@@ -125,3 +158,38 @@ fn do_upload(buffer: Vec<u8>, asset_id: u64, cookie: &str) -> anyhow::Result<()>
 
     Ok(())
 }
+
+/// Implementation of do_upload that supports the new open cloud api.
+/// see https://developer.roblox.com/en-us/articles/open-cloud
+fn do_upload_open_cloud(
+    buffer: Vec<u8>,
+    universe_id: u64,
+    asset_id: u64,
+    api_key: &str,
+) -> anyhow::Result<()> {
+    let url = format!(
+        "https://apis.roblox.com/universes/v1/{}/places/{}/versions?versionType=Published",
+        universe_id, asset_id
+    );
+
+    let client = reqwest::Client::new();
+
+    log::debug!("Uploading to Roblox...");
+    let mut response = client
+        .post(&url)
+        .header("x-api-key", api_key)
+        .header(CONTENT_TYPE, "application/xml")
+        .header(ACCEPT, "application/json")
+        .body(buffer)
+        .send()?;
+
+    let status = response.status();
+    if !status.is_success() {
+        bail!(
+            "The Roblox API returned an unexpected error: {}",
+            response.text()?
+        );
+    }
+
+    Ok(())
+}

src/project.rs

@@ -1,6 +1,7 @@
 use std::{
     collections::{BTreeMap, HashMap, HashSet},
     fs, io,
+    net::IpAddr,
     path::{Path, PathBuf},
 };
 
@@ -67,6 +68,11 @@ pub struct Project {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub game_id: Option<u64>,
 
+    /// If specified, this address will be used in place of the default address
+    /// As long as --address is unprovided.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub serve_address: Option<IpAddr>,
+
     /// A list of globs, relative to the folder the project file is in, that
     /// match files that should be excluded if Rojo encounters them.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
@@ -168,6 +174,35 @@ impl Project {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize)]
+pub struct OptionalPathNode {
+    #[serde(serialize_with = "crate::path_serializer::serialize_absolute")]
+    pub optional: PathBuf,
+}
+
+impl OptionalPathNode {
+    pub fn new(optional: PathBuf) -> Self {
+        OptionalPathNode { optional }
+    }
+}
+
+/// Describes a path that is either optional or required
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum PathNode {
+    Required(#[serde(serialize_with = "crate::path_serializer::serialize_absolute")] PathBuf),
+    Optional(OptionalPathNode),
+}
+
+impl PathNode {
+    pub fn path(&self) -> &Path {
+        match self {
+            PathNode::Required(pathbuf) => &pathbuf,
+            PathNode::Optional(OptionalPathNode { optional }) => &optional,
+        }
+    }
+}
+
 /// Describes an instance and its descendants in a project.
 #[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize)]
 pub struct ProjectNode {
@@ -218,12 +253,8 @@ pub struct ProjectNode {
     /// path can point to any file type supported by Rojo, including Lua files
     /// (`.lua`), Roblox models (`.rbxm`, `.rbxmx`), and localization table
     /// spreadsheets (`.csv`).
-    #[serde(
-        rename = "$path",
-        serialize_with = "crate::path_serializer::serialize_option_absolute",
-        skip_serializing_if = "Option::is_none"
-    )]
-    pub path: Option<PathBuf>,
+    #[serde(rename = "$path", skip_serializing_if = "Option::is_none")]
+    pub path: Option<PathNode>,
 }
 
 impl ProjectNode {
@@ -243,3 +274,106 @@ impl ProjectNode {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn path_node_required() {
+        let path_node: PathNode = serde_json::from_str(r#""src""#).unwrap();
+        assert_eq!(path_node, PathNode::Required(PathBuf::from("src")));
+    }
+
+    #[test]
+    fn path_node_optional() {
+        let path_node: PathNode = serde_json::from_str(r#"{ "optional": "src" }"#).unwrap();
+        assert_eq!(
+            path_node,
+            PathNode::Optional(OptionalPathNode::new(PathBuf::from("src")))
+        );
+    }
+
+    #[test]
+    fn project_node_required() {
+        let project_node: ProjectNode = serde_json::from_str(
+            r#"{
+                "$path": "src"
+            }"#,
+        )
+        .unwrap();
+
+        assert_eq!(
+            project_node.path,
+            Some(PathNode::Required(PathBuf::from("src")))
+        );
+    }
+
+    #[test]
+    fn project_node_optional() {
+        let project_node: ProjectNode = serde_json::from_str(
+            r#"{
+                "$path": { "optional": "src" }
+            }"#,
+        )
+        .unwrap();
+
+        assert_eq!(
+            project_node.path,
+            Some(PathNode::Optional(OptionalPathNode::new(PathBuf::from(
+                "src"
+            ))))
+        );
+    }
+
+    #[test]
+    fn project_node_none() {
+        let project_node: ProjectNode = serde_json::from_str(
+            r#"{
+                "$className": "Folder"
+            }"#,
+        )
+        .unwrap();
+
+        assert_eq!(project_node.path, None);
+    }
+
+    #[test]
+    fn project_node_optional_serialize_absolute() {
+        let project_node: ProjectNode = serde_json::from_str(
+            r#"{
+                "$path": { "optional": "..\\src" }
+            }"#,
+        )
+        .unwrap();
+
+        let serialized = serde_json::to_string(&project_node).unwrap();
+        assert_eq!(serialized, r#"{"$path":{"optional":"../src"}}"#);
+    }
+
+    #[test]
+    fn project_node_optional_serialize_absolute_no_change() {
+        let project_node: ProjectNode = serde_json::from_str(
+            r#"{
+                "$path": { "optional": "../src" }
+            }"#,
+        )
+        .unwrap();
+
+        let serialized = serde_json::to_string(&project_node).unwrap();
+        assert_eq!(serialized, r#"{"$path":{"optional":"../src"}}"#);
+    }
+
+    #[test]
+    fn project_node_optional_serialize_optional() {
+        let project_node: ProjectNode = serde_json::from_str(
+            r#"{
+                "$path": "..\\src"
+            }"#,
+        )
+        .unwrap();
+
+        let serialized = serde_json::to_string(&project_node).unwrap();
+        assert_eq!(serialized, r#"{"$path":"../src"}"#);
+    }
+}

src/resolution.rs

@@ -1,7 +1,9 @@
 use std::borrow::Borrow;
 
 use anyhow::format_err;
-use rbx_dom_weak::types::{Color3, Content, Enum, Variant, VariantType, Vector2, Vector3};
+use rbx_dom_weak::types::{
+    CFrame, Color3, Content, Enum, Matrix3, Tags, Variant, VariantType, Vector2, Vector3,
+};
 use rbx_reflection::{DataType, PropertyDescriptor};
 use serde::{Deserialize, Serialize};
 
@@ -32,10 +34,12 @@ impl UnresolvedValue {
 pub enum AmbiguousValue {
     Bool(bool),
     String(String),
+    StringArray(Vec<String>),
     Number(f64),
     Array2([f64; 2]),
     Array3([f64; 3]),
     Array4([f64; 4]),
+    Array12([f64; 12]),
 }
 
 impl AmbiguousValue {
@@ -93,6 +97,9 @@ impl AmbiguousValue {
                 (VariantType::Int64, AmbiguousValue::Number(value)) => Ok((value as i64).into()),
 
                 (VariantType::String, AmbiguousValue::String(value)) => Ok(value.into()),
+                (VariantType::Tags, AmbiguousValue::StringArray(value)) => {
+                    Ok(Tags::from(value).into())
+                }
                 (VariantType::Content, AmbiguousValue::String(value)) => {
                     Ok(Content::from(value).into())
                 }
@@ -109,6 +116,18 @@ impl AmbiguousValue {
                     Ok(Color3::new(value[0] as f32, value[1] as f32, value[2] as f32).into())
                 }
 
+                (VariantType::CFrame, AmbiguousValue::Array12(value)) => {
+                    let value = value.map(|v| v as f32);
+                    let pos = Vector3::new(value[0], value[1], value[2]);
+                    let orientation = Matrix3::new(
+                        Vector3::new(value[3], value[4], value[5]),
+                        Vector3::new(value[6], value[7], value[8]),
+                        Vector3::new(value[9], value[10], value[11]),
+                    );
+
+                    Ok(CFrame::new(pos, orientation).into())
+                }
+
                 (_, unresolved) => Err(format_err!(
                     "Wrong type of value for property {}.{}. Expected {:?}, got {}",
                     class_name,
@@ -129,10 +148,12 @@ impl AmbiguousValue {
         match self {
             AmbiguousValue::Bool(_) => "a bool",
             AmbiguousValue::String(_) => "a string",
+            AmbiguousValue::StringArray(_) => "an array of strings",
             AmbiguousValue::Number(_) => "a number",
             AmbiguousValue::Array2(_) => "an array of two numbers",
             AmbiguousValue::Array3(_) => "an array of three numbers",
             AmbiguousValue::Array4(_) => "an array of four numbers",
+            AmbiguousValue::Array12(_) => "an array of twelve numbers",
         }
     }
 }

src/serve_session.rs

@@ -2,6 +2,7 @@ use std::{
     borrow::Cow,
     collections::HashSet,
     io,
+    net::IpAddr,
     path::{Path, PathBuf},
     sync::{Arc, Mutex, MutexGuard},
     time::Instant,
@@ -126,11 +127,10 @@ impl ServeSession {
         let instance_context = InstanceContext::default();
 
         log::trace!("Generating snapshot of instances from VFS");
-        let snapshot = snapshot_from_vfs(&instance_context, &vfs, &start_path)?
-            .expect("snapshot did not return an instance");
+        let snapshot = snapshot_from_vfs(&instance_context, &vfs, &start_path)?;
 
         log::trace!("Computing initial patch set");
-        let patch_set = compute_patch_set(&snapshot, &tree, root_id);
+        let patch_set = compute_patch_set(snapshot.as_ref(), &tree, root_id);
 
         log::trace!("Applying initial patch set");
         apply_patch_set(&mut tree, patch_set);
@@ -212,6 +212,10 @@ impl ServeSession {
     pub fn serve_place_ids(&self) -> Option<&HashSet<u64>> {
         self.root_project.serve_place_ids.as_ref()
     }
+
+    pub fn serve_address(&self) -> Option<IpAddr> {
+        self.root_project.serve_address
+    }
 }
 
 #[derive(Debug, Error)]

src/snapshot/patch_compute.rs

@@ -10,16 +10,27 @@ use super::{
     InstanceSnapshot, InstanceWithMeta, RojoTree,
 };
 
-pub fn compute_patch_set(snapshot: &InstanceSnapshot, tree: &RojoTree, id: Ref) -> PatchSet {
+pub fn compute_patch_set(
+    snapshot: Option<&InstanceSnapshot>,
+    tree: &RojoTree,
+    id: Ref,
+) -> PatchSet {
     let mut patch_set = PatchSet::new();
-    let mut context = ComputePatchContext::default();
 
-    compute_patch_set_internal(&mut context, snapshot, tree, id, &mut patch_set);
+    if let Some(snapshot) = snapshot {
+        let mut context = ComputePatchContext::default();
 
-    // Rewrite Ref properties to refer to instance IDs instead of snapshot IDs
-    // for all of the IDs that we know about so far.
-    rewrite_refs_in_updates(&context, &mut patch_set.updated_instances);
-    rewrite_refs_in_additions(&context, &mut patch_set.added_instances);
+        compute_patch_set_internal(&mut context, snapshot, tree, id, &mut patch_set);
+
+        // Rewrite Ref properties to refer to instance IDs instead of snapshot IDs
+        // for all of the IDs that we know about so far.
+        rewrite_refs_in_updates(&context, &mut patch_set.updated_instances);
+        rewrite_refs_in_additions(&context, &mut patch_set.added_instances);
+    } else {
+        if id != tree.get_root_id() {
+            patch_set.removed_instances.push(id);
+        }
+    }
 
     patch_set
 }
@@ -246,7 +257,7 @@ mod test {
             children: Vec::new(),
         };
 
-        let patch_set = compute_patch_set(&snapshot, &tree, root_id);
+        let patch_set = compute_patch_set(Some(&snapshot), &tree, root_id);
 
         let expected_patch_set = PatchSet {
             updated_instances: vec![PatchUpdate {
@@ -296,7 +307,7 @@ mod test {
             class_name: Cow::Borrowed("foo"),
         };
 
-        let patch_set = compute_patch_set(&snapshot, &tree, root_id);
+        let patch_set = compute_patch_set(Some(&snapshot), &tree, root_id);
 
         let expected_patch_set = PatchSet {
             added_instances: vec![PatchAdd {

src/snapshot/tests/compute.rs

@@ -23,7 +23,7 @@ fn set_name_and_class_name() {
         children: Vec::new(),
     };
 
-    let patch_set = compute_patch_set(&snapshot, &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
     let patch_value = redactions.redacted_yaml(patch_set);
 
     assert_yaml_snapshot!(patch_value);
@@ -47,7 +47,7 @@ fn set_property() {
         children: Vec::new(),
     };
 
-    let patch_set = compute_patch_set(&snapshot, &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
     let patch_value = redactions.redacted_yaml(patch_set);
 
     assert_yaml_snapshot!(patch_value);
@@ -78,7 +78,7 @@ fn remove_property() {
         children: Vec::new(),
     };
 
-    let patch_set = compute_patch_set(&snapshot, &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
     let patch_value = redactions.redacted_yaml(patch_set);
 
     assert_yaml_snapshot!(patch_value);
@@ -107,7 +107,7 @@ fn add_child() {
         }],
     };
 
-    let patch_set = compute_patch_set(&snapshot, &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
     let patch_value = redactions.redacted_yaml(patch_set);
 
     assert_yaml_snapshot!(patch_value);
@@ -139,7 +139,7 @@ fn remove_child() {
         children: Vec::new(),
     };
 
-    let patch_set = compute_patch_set(&snapshot, &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
     let patch_value = redactions.redacted_yaml(patch_set);
 
     assert_yaml_snapshot!(patch_value);

src/snapshot_middleware/csv.rs

@@ -7,15 +7,16 @@ use serde::Serialize;
 
 use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
-use super::{meta_file::AdjacentMetadata, middleware::SnapshotInstanceResult};
+use super::{meta_file::AdjacentMetadata, util::PathExt};
 
 pub fn snapshot_csv(
     _context: &InstanceContext,
     vfs: &Vfs,
     path: &Path,
-    instance_name: &str,
-) -> SnapshotInstanceResult {
-    let meta_path = path.with_file_name(format!("{}.meta.json", instance_name));
+) -> anyhow::Result<Option<InstanceSnapshot>> {
+    let name = path.file_name_trim_end(".csv")?;
+
+    let meta_path = path.with_file_name(format!("{}.meta.json", name));
     let contents = vfs.read(path)?;
 
     let table_contents = convert_localization_csv(&contents).with_context(|| {
@@ -26,7 +27,7 @@ pub fn snapshot_csv(
     })?;
 
     let mut snapshot = InstanceSnapshot::new()
-        .name(instance_name)
+        .name(name)
         .class_name("LocalizationTable")
         .properties(hashmap! {
             "Contents".to_owned() => table_contents.into(),
@@ -143,14 +144,10 @@ Ack,Ack!,,An exclamation of despair,¡Ay!"#,
 
         let mut vfs = Vfs::new(imfs);
 
-        let instance_snapshot = snapshot_csv(
-            &InstanceContext::default(),
-            &mut vfs,
-            Path::new("/foo.csv"),
-            "foo",
-        )
-        .unwrap()
-        .unwrap();
+        let instance_snapshot =
+            snapshot_csv(&InstanceContext::default(), &mut vfs, Path::new("/foo.csv"))
+                .unwrap()
+                .unwrap();
 
         insta::assert_yaml_snapshot!(instance_snapshot);
     }
@@ -175,14 +172,10 @@ Ack,Ack!,,An exclamation of despair,¡Ay!"#,
 
         let mut vfs = Vfs::new(imfs);
 
-        let instance_snapshot = snapshot_csv(
-            &InstanceContext::default(),
-            &mut vfs,
-            Path::new("/foo.csv"),
-            "foo",
-        )
-        .unwrap()
-        .unwrap();
+        let instance_snapshot =
+            snapshot_csv(&InstanceContext::default(), &mut vfs, Path::new("/foo.csv"))
+                .unwrap()
+                .unwrap();
 
         insta::assert_yaml_snapshot!(instance_snapshot);
     }

src/snapshot_middleware/dir.rs

@@ -4,9 +4,13 @@ use memofs::{DirEntry, IoResultExt, Vfs};
 
 use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
-use super::{meta_file::DirectoryMetadata, middleware::SnapshotInstanceResult, snapshot_from_vfs};
+use super::{meta_file::DirectoryMetadata, snapshot_from_vfs};
 
-pub fn snapshot_dir(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+pub fn snapshot_dir(
+    context: &InstanceContext,
+    vfs: &Vfs,
+    path: &Path,
+) -> anyhow::Result<Option<InstanceSnapshot>> {
     let passes_filter_rules = |child: &DirEntry| {
         context
             .path_ignore_rules

src/snapshot_middleware/json.rs

@@ -9,14 +9,14 @@ use crate::{
     snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
 };
 
-use super::{meta_file::AdjacentMetadata, middleware::SnapshotInstanceResult};
+use super::{meta_file::AdjacentMetadata, util::PathExt};
 
 pub fn snapshot_json(
     context: &InstanceContext,
     vfs: &Vfs,
     path: &Path,
-    instance_name: &str,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
+    let name = path.file_name_trim_end(".json")?;
     let contents = vfs.read(path)?;
 
     let value: serde_json::Value = serde_json::from_slice(&contents)
@@ -28,10 +28,10 @@ pub fn snapshot_json(
         "Source".to_owned() => as_lua.into(),
     };
 
-    let meta_path = path.with_file_name(format!("{}.meta.json", instance_name));
+    let meta_path = path.with_file_name(format!("{}.meta.json", name));
 
     let mut snapshot = InstanceSnapshot::new()
-        .name(instance_name)
+        .name(name)
         .class_name("ModuleScript")
         .properties(properties)
         .metadata(
@@ -107,7 +107,6 @@ mod test {
             &InstanceContext::default(),
             &mut vfs,
             Path::new("/foo.json"),
-            "foo",
         )
         .unwrap()
         .unwrap();

src/snapshot_middleware/json_model.rs

@@ -9,14 +9,15 @@ use crate::{
     snapshot::{InstanceContext, InstanceSnapshot},
 };
 
-use super::middleware::SnapshotInstanceResult;
+use super::util::PathExt;
 
 pub fn snapshot_json_model(
     context: &InstanceContext,
     vfs: &Vfs,
     path: &Path,
-    instance_name: &str,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
+    let name = path.file_name_trim_end(".model.json")?;
+
     let contents = vfs.read(path)?;
     let contents_str = str::from_utf8(&contents)
         .with_context(|| format!("File was not valid UTF-8: {}", path.display()))?;
@@ -30,7 +31,7 @@ pub fn snapshot_json_model(
 
     let mut snapshot = instance
         .core
-        .into_snapshot(instance_name.to_owned())
+        .into_snapshot(name.to_owned())
         .with_context(|| format!("Could not load JSON model: {}", path.display()))?;
 
     snapshot.metadata = snapshot
@@ -135,7 +136,6 @@ mod test {
             &InstanceContext::default(),
             &mut vfs,
             Path::new("/foo.model.json"),
-            "foo",
         )
         .unwrap()
         .unwrap();

src/snapshot_middleware/lua.rs

@@ -6,13 +6,14 @@ use memofs::{IoResultExt, Vfs};
 
 use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
-use super::{
-    dir::snapshot_dir, meta_file::AdjacentMetadata, middleware::SnapshotInstanceResult,
-    util::match_trailing,
-};
+use super::{dir::snapshot_dir, meta_file::AdjacentMetadata, util::match_trailing};
 
 /// Core routine for turning Lua files into snapshots.
-pub fn snapshot_lua(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+pub fn snapshot_lua(
+    context: &InstanceContext,
+    vfs: &Vfs,
+    path: &Path,
+) -> anyhow::Result<Option<InstanceSnapshot>> {
     let file_name = path.file_name().unwrap().to_string_lossy();
 
     let (class_name, instance_name) = if let Some(name) = match_trailing(&file_name, ".server.lua")
@@ -63,7 +64,7 @@ pub fn snapshot_lua_init(
     context: &InstanceContext,
     vfs: &Vfs,
     init_path: &Path,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
     let folder_path = init_path.parent().unwrap();
     let dir_snapshot = snapshot_dir(context, vfs, folder_path)?.unwrap();
 
@@ -71,8 +72,8 @@ pub fn snapshot_lua_init(
         anyhow::bail!(
             "init.lua, init.server.lua, and init.client.lua can \
              only be used if the instance produced by the containing \
-             directory would be a Folder.\n\n\
-
+             directory would be a Folder.\n\
+             \n\
              The directory {} turned into an instance of class {}.",
             folder_path.display(),
             dir_snapshot.class_name

src/snapshot_middleware/middleware.rs

@@ -1,3 +0,0 @@
-use crate::snapshot::InstanceSnapshot;
-
-pub type SnapshotInstanceResult = anyhow::Result<Option<InstanceSnapshot>>;

src/snapshot_middleware/mod.rs

@@ -11,7 +11,6 @@ mod json;
 mod json_model;
 mod lua;
 mod meta_file;
-mod middleware;
 mod project;
 mod rbxm;
 mod rbxmx;
@@ -22,7 +21,7 @@ use std::path::Path;
 
 use memofs::{IoResultExt, Vfs};
 
-use crate::snapshot::InstanceContext;
+use crate::snapshot::{InstanceContext, InstanceSnapshot};
 
 use self::{
     csv::snapshot_csv,
@@ -30,12 +29,11 @@ use self::{
     json::snapshot_json,
     json_model::snapshot_json_model,
     lua::{snapshot_lua, snapshot_lua_init},
-    middleware::SnapshotInstanceResult,
     project::snapshot_project,
     rbxm::snapshot_rbxm,
     rbxmx::snapshot_rbxmx,
     txt::snapshot_txt,
-    util::match_file_name,
+    util::PathExt,
 };
 
 pub use self::project::snapshot_project_node;
@@ -46,7 +44,7 @@ pub fn snapshot_from_vfs(
     context: &InstanceContext,
     vfs: &Vfs,
     path: &Path,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
     let meta = match vfs.metadata(path).with_not_found()? {
         Some(meta) => meta,
         None => return Ok(None),
@@ -75,7 +73,7 @@ pub fn snapshot_from_vfs(
 
         snapshot_dir(context, vfs, path)
     } else {
-        if let Some(name) = match_file_name(path, ".lua") {
+        if let Ok(name) = path.file_name_trim_end(".lua") {
             match name {
                 // init scripts are handled elsewhere and should not turn into
                 // their own children.
@@ -83,23 +81,23 @@ pub fn snapshot_from_vfs(
 
                 _ => return snapshot_lua(context, vfs, path),
             }
-        } else if let Some(_name) = match_file_name(path, ".project.json") {
+        } else if path.file_name_ends_with(".project.json") {
             return snapshot_project(context, vfs, path);
-        } else if let Some(name) = match_file_name(path, ".model.json") {
-            return snapshot_json_model(context, vfs, path, name);
-        } else if let Some(_name) = match_file_name(path, ".meta.json") {
+        } else if path.file_name_ends_with(".model.json") {
+            return snapshot_json_model(context, vfs, path);
+        } else if path.file_name_ends_with(".meta.json") {
             // .meta.json files do not turn into their own instances.
             return Ok(None);
-        } else if let Some(name) = match_file_name(path, ".json") {
-            return snapshot_json(context, vfs, path, name);
-        } else if let Some(name) = match_file_name(path, ".csv") {
-            return snapshot_csv(context, vfs, path, name);
-        } else if let Some(name) = match_file_name(path, ".txt") {
-            return snapshot_txt(context, vfs, path, name);
-        } else if let Some(name) = match_file_name(path, ".rbxmx") {
-            return snapshot_rbxmx(context, vfs, path, name);
-        } else if let Some(name) = match_file_name(path, ".rbxm") {
-            return snapshot_rbxm(context, vfs, path, name);
+        } else if path.file_name_ends_with(".json") {
+            return snapshot_json(context, vfs, path);
+        } else if path.file_name_ends_with(".csv") {
+            return snapshot_csv(context, vfs, path);
+        } else if path.file_name_ends_with(".txt") {
+            return snapshot_txt(context, vfs, path);
+        } else if path.file_name_ends_with(".rbxmx") {
+            return snapshot_rbxmx(context, vfs, path);
+        } else if path.file_name_ends_with(".rbxm") {
+            return snapshot_rbxm(context, vfs, path);
         }
 
         Ok(None)

src/snapshot_middleware/project.rs

@@ -5,19 +5,19 @@ use memofs::Vfs;
 use rbx_reflection::ClassTag;
 
 use crate::{
-    project::{Project, ProjectNode},
+    project::{PathNode, Project, ProjectNode},
     snapshot::{
         InstanceContext, InstanceMetadata, InstanceSnapshot, InstigatingSource, PathIgnoreRule,
     },
 };
 
-use super::{middleware::SnapshotInstanceResult, snapshot_from_vfs};
+use super::snapshot_from_vfs;
 
 pub fn snapshot_project(
     context: &InstanceContext,
     vfs: &Vfs,
     path: &Path,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
     let project = Project::load_from_slice(&vfs.read(path)?, path)
         .with_context(|| format!("File was not a valid Rojo project: {}", path.display()))?;
 
@@ -30,30 +30,31 @@ pub fn snapshot_project(
 
     context.add_path_ignore_rules(rules);
 
-    // TODO: If this project node is a path to an instance that Rojo doesn't
-    // understand, this may panic!
-    let mut snapshot =
-        snapshot_project_node(&context, path, &project.name, &project.tree, vfs, None)?.unwrap();
+    match snapshot_project_node(&context, path, &project.name, &project.tree, vfs, None)? {
+        Some(found_snapshot) => {
+            let mut snapshot = found_snapshot;
+            // Setting the instigating source to the project file path is a little
+            // coarse.
+            //
+            // Ideally, we'd only snapshot the project file if the project file
+            // actually changed. Because Rojo only has the concept of one
+            // relevant path -> snapshot path mapping per instance, we pick the more
+            // conservative approach of snapshotting the project file if any
+            // relevant paths changed.
+            snapshot.metadata.instigating_source = Some(path.to_path_buf().into());
 
-    // Setting the instigating source to the project file path is a little
-    // coarse.
-    //
-    // Ideally, we'd only snapshot the project file if the project file
-    // actually changed. Because Rojo only has the concept of one
-    // relevant path -> snapshot path mapping per instance, we pick the more
-    // conservative approach of snapshotting the project file if any
-    // relevant paths changed.
-    snapshot.metadata.instigating_source = Some(path.to_path_buf().into());
+            // Mark this snapshot (the root node of the project file) as being
+            // related to the project file.
+            //
+            // We SHOULD NOT mark the project file as a relevant path for any
+            // nodes that aren't roots. They'll be updated as part of the project
+            // file being updated.
+            snapshot.metadata.relevant_paths.push(path.to_path_buf());
 
-    // Mark this snapshot (the root node of the project file) as being
-    // related to the project file.
-    //
-    // We SHOULD NOT mark the project file as a relevant path for any
-    // nodes that aren't roots. They'll be updated as part of the project
-    // file being updated.
-    snapshot.metadata.relevant_paths.push(path.to_path_buf());
-
-    Ok(Some(snapshot))
+            Ok(Some(snapshot))
+        }
+        None => Ok(None),
+    }
 }
 
 pub fn snapshot_project_node(
@@ -63,7 +64,7 @@ pub fn snapshot_project_node(
     node: &ProjectNode,
     vfs: &Vfs,
     parent_class: Option<&str>,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
     let project_folder = project_path.parent().unwrap();
 
     let class_name_from_project = node
@@ -77,16 +78,18 @@ pub fn snapshot_project_node(
     let mut children = Vec::new();
     let mut metadata = InstanceMetadata::default();
 
-    if let Some(path) = &node.path {
+    if let Some(path_node) = &node.path {
+        let path = path_node.path();
+
         // If the path specified in the project is relative, we assume it's
         // relative to the folder that the project is in, project_folder.
-        let path = if path.is_relative() {
+        let full_path = if path.is_relative() {
             Cow::Owned(project_folder.join(path))
         } else {
             Cow::Borrowed(path)
         };
 
-        if let Some(snapshot) = snapshot_from_vfs(context, vfs, &path)? {
+        if let Some(snapshot) = snapshot_from_vfs(context, vfs, &full_path)? {
             class_name_from_path = Some(snapshot.class_name);
 
             // Properties from the snapshot are pulled in unchanged, and
@@ -106,11 +109,6 @@ pub fn snapshot_project_node(
             // Take the snapshot's metadata as-is, which will be mutated later
             // on.
             metadata = snapshot.metadata;
-        } else {
-            // TODO: Should this issue an error instead?
-            log::warn!(
-                "$path referred to a path that could not be turned into an instance by Rojo"
-            );
         }
     }
 
@@ -120,20 +118,21 @@ pub fn snapshot_project_node(
         class_name_from_project,
         class_name_from_path,
         class_name_from_inference,
+        &node.path,
     ) {
         // These are the easy, happy paths!
-        (Some(project), None, None) => project,
-        (None, Some(path), None) => path,
-        (None, None, Some(inference)) => inference,
+        (Some(project), None, None, _) => project,
+        (None, Some(path), None, _) => path,
+        (None, None, Some(inference), _) => inference,
 
         // If the user specifies a class name, but there's an inferred class
         // name, we prefer the name listed explicitly by the user.
-        (Some(project), None, Some(_)) => project,
+        (Some(project), None, Some(_), _) => project,
 
         // If the user has a $path pointing to a folder and we're able to infer
         // a class name, let's use the inferred name. If the path we're pointing
         // to isn't a folder, though, that's a user error.
-        (None, Some(path), Some(inference)) => {
+        (None, Some(path), Some(inference), _) => {
             if path == "Folder" {
                 inference
             } else {
@@ -141,7 +140,7 @@ pub fn snapshot_project_node(
             }
         }
 
-        (Some(project), Some(path), _) => {
+        (Some(project), Some(path), _, _) => {
             if path == "Folder" {
                 project
             } else {
@@ -155,12 +154,28 @@ pub fn snapshot_project_node(
                     project,
                     path,
                     project_path.display(),
-                    node.path.as_ref().unwrap().display()
+                    node.path.as_ref().unwrap().path().display()
                 );
             }
         }
 
-        (None, None, None) => {
+        (None, None, None, Some(PathNode::Optional(_))) => {
+            return Ok(None);
+        }
+
+        (_, None, _, Some(PathNode::Required(path))) => {
+            anyhow::bail!(
+                "Rojo project referred to a file using $path that could not be turned into a Roblox Instance by Rojo.\n\
+                Check that the file exists and is a file type known by Rojo.\n\
+                \n\
+                Project path: {}\n\
+                File $path: {}",
+                project_path.display(),
+                path.display(),
+            );
+        }
+
+        (None, None, None, None) => {
             bail!(
                 "Instance \"{}\" is missing some required information.\n\
                  One of the following must be true:\n\

src/snapshot_middleware/rbxm.rs

@@ -5,14 +5,15 @@ use memofs::Vfs;
 
 use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
-use super::middleware::SnapshotInstanceResult;
+use super::util::PathExt;
 
 pub fn snapshot_rbxm(
     context: &InstanceContext,
     vfs: &Vfs,
     path: &Path,
-    instance_name: &str,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
+    let name = path.file_name_trim_end(".rbxm")?;
+
     let temp_tree = rbx_binary::from_reader(vfs.read(path)?.as_slice())
         .with_context(|| format!("Malformed rbxm file: {}", path.display()))?;
 
@@ -21,7 +22,7 @@ pub fn snapshot_rbxm(
 
     if children.len() == 1 {
         let snapshot = InstanceSnapshot::from_tree(&temp_tree, children[0])
-            .name(instance_name)
+            .name(name)
             .metadata(
                 InstanceMetadata::new()
                     .instigating_source(path)
@@ -60,7 +61,6 @@ mod test {
             &InstanceContext::default(),
             &mut vfs,
             Path::new("/foo.rbxm"),
-            "foo",
         )
         .unwrap()
         .unwrap();

src/snapshot_middleware/rbxmx.rs

@@ -5,14 +5,15 @@ use memofs::Vfs;
 
 use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
-use super::middleware::SnapshotInstanceResult;
+use super::util::PathExt;
 
 pub fn snapshot_rbxmx(
     context: &InstanceContext,
     vfs: &Vfs,
     path: &Path,
-    instance_name: &str,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
+    let name = path.file_name_trim_end(".rbxmx")?;
+
     let options = rbx_xml::DecodeOptions::new()
         .property_behavior(rbx_xml::DecodePropertyBehavior::ReadUnknown);
 
@@ -24,7 +25,7 @@ pub fn snapshot_rbxmx(
 
     if children.len() == 1 {
         let snapshot = InstanceSnapshot::from_tree(&temp_tree, children[0])
-            .name(instance_name)
+            .name(name)
             .metadata(
                 InstanceMetadata::new()
                     .instigating_source(path)
@@ -73,7 +74,6 @@ mod test {
             &InstanceContext::default(),
             &mut vfs,
             Path::new("/foo.rbxmx"),
-            "foo",
         )
         .unwrap()
         .unwrap();

src/snapshot_middleware/txt.rs

@@ -6,14 +6,15 @@ use memofs::{IoResultExt, Vfs};
 
 use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
-use super::{meta_file::AdjacentMetadata, middleware::SnapshotInstanceResult};
+use super::{meta_file::AdjacentMetadata, util::PathExt};
 
 pub fn snapshot_txt(
     context: &InstanceContext,
     vfs: &Vfs,
     path: &Path,
-    instance_name: &str,
-) -> SnapshotInstanceResult {
+) -> anyhow::Result<Option<InstanceSnapshot>> {
+    let name = path.file_name_trim_end(".txt")?;
+
     let contents = vfs.read(path)?;
     let contents_str = str::from_utf8(&contents)
         .with_context(|| format!("File was not valid UTF-8: {}", path.display()))?
@@ -23,10 +24,10 @@ pub fn snapshot_txt(
         "Value".to_owned() => contents_str.into(),
     };
 
-    let meta_path = path.with_file_name(format!("{}.meta.json", instance_name));
+    let meta_path = path.with_file_name(format!("{}.meta.json", name));
 
     let mut snapshot = InstanceSnapshot::new()
-        .name(instance_name)
+        .name(name)
         .class_name("StringValue")
         .properties(properties)
         .metadata(
@@ -58,14 +59,10 @@ mod test {
 
         let mut vfs = Vfs::new(imfs.clone());
 
-        let instance_snapshot = snapshot_txt(
-            &InstanceContext::default(),
-            &mut vfs,
-            Path::new("/foo.txt"),
-            "foo",
-        )
-        .unwrap()
-        .unwrap();
+        let instance_snapshot =
+            snapshot_txt(&InstanceContext::default(), &mut vfs, Path::new("/foo.txt"))
+                .unwrap()
+                .unwrap();
 
         insta::assert_yaml_snapshot!(instance_snapshot);
     }

src/snapshot_middleware/util.rs

@@ -1,5 +1,7 @@
 use std::path::Path;
 
+use anyhow::Context;
+
 /// If the given string ends up with the given suffix, returns the portion of
 /// the string before the suffix.
 pub fn match_trailing<'a>(input: &'a str, suffix: &str) -> Option<&'a str> {
@@ -11,10 +13,31 @@ pub fn match_trailing<'a>(input: &'a str, suffix: &str) -> Option<&'a str> {
     }
 }
 
-/// If the given path has a file name, and that file name ends with the given
-/// suffix, returns the portion of the file name before the given suffix.
-pub fn match_file_name<'a>(path: &'a Path, suffix: &str) -> Option<&'a str> {
-    let file_name = path.file_name()?.to_str()?;
-
-    match_trailing(&file_name, suffix)
+pub trait PathExt {
+    fn file_name_ends_with(&self, suffix: &str) -> bool;
+    fn file_name_trim_end<'a>(&'a self, suffix: &str) -> anyhow::Result<&'a str>;
+}
+
+impl<P> PathExt for P
+where
+    P: AsRef<Path>,
+{
+    fn file_name_ends_with(&self, suffix: &str) -> bool {
+        self.as_ref()
+            .file_name()
+            .and_then(|name| name.to_str())
+            .map(|name| name.ends_with(suffix))
+            .unwrap_or(false)
+    }
+
+    fn file_name_trim_end<'a>(&'a self, suffix: &str) -> anyhow::Result<&'a str> {
+        let path = self.as_ref();
+        let file_name = path
+            .file_name()
+            .and_then(|name| name.to_str())
+            .with_context(|| format!("Path did not have a file name: {}", path.display()))?;
+
+        match_trailing(&file_name, suffix)
+            .with_context(|| format!("Path did not end in {}: {}", suffix, path.display()))
+    }
 }

src/web/api.rs

@@ -11,9 +11,9 @@ use crate::{
     snapshot::{InstanceWithMeta, PatchSet, PatchUpdate},
     web::{
         interface::{
-            ErrorResponse, Instance, InstanceMetadata as WebInstanceMetadata, InstanceUpdate,
-            OpenResponse, ReadResponse, ServerInfoResponse, SubscribeMessage, SubscribeResponse,
-            WriteRequest, WriteResponse, PROTOCOL_VERSION, SERVER_VERSION,
+            ErrorResponse, Instance, OpenResponse, ReadResponse, ServerInfoResponse,
+            SubscribeMessage, SubscribeResponse, WriteRequest, WriteResponse, PROTOCOL_VERSION,
+            SERVER_VERSION,
         },
         util::{json, json_ok},
     },
@@ -99,44 +99,7 @@ impl ApiService {
 
                 let api_messages = messages
                     .into_iter()
-                    .map(|message| {
-                        let removed = message.removed;
-
-                        let mut added = HashMap::new();
-                        for id in message.added {
-                            let instance = tree.get_instance(id).unwrap();
-                            added.insert(id, Instance::from_rojo_instance(instance));
-
-                            for instance in tree.descendants(id) {
-                                added.insert(instance.id(), Instance::from_rojo_instance(instance));
-                            }
-                        }
-
-                        let updated = message
-                            .updated
-                            .into_iter()
-                            .map(|update| {
-                                let changed_metadata = update
-                                    .changed_metadata
-                                    .as_ref()
-                                    .map(WebInstanceMetadata::from_rojo_metadata);
-
-                                InstanceUpdate {
-                                    id: update.id,
-                                    changed_name: update.changed_name,
-                                    changed_class_name: update.changed_class_name,
-                                    changed_properties: update.changed_properties,
-                                    changed_metadata,
-                                }
-                            })
-                            .collect();
-
-                        SubscribeMessage {
-                            removed,
-                            added,
-                            updated,
-                        }
-                    })
+                    .map(|patch| SubscribeMessage::from_patch_update(&tree, patch))
                     .collect();
 
                 json_ok(SubscribeResponse {

src/web/interface.rs

@@ -7,12 +7,14 @@ use std::{
     collections::{HashMap, HashSet},
 };
 
-use rbx_dom_weak::types::{Ref, Variant};
+use rbx_dom_weak::types::{Ref, Variant, VariantType};
 use serde::{Deserialize, Serialize};
 
 use crate::{
     session_id::SessionId,
-    snapshot::{InstanceMetadata as RojoInstanceMetadata, InstanceWithMeta},
+    snapshot::{
+        AppliedPatchSet, InstanceMetadata as RojoInstanceMetadata, InstanceWithMeta, RojoTree,
+    },
 };
 
 /// Server version to report over the API, not exposed outside this crate.
@@ -30,6 +32,53 @@ pub struct SubscribeMessage<'a> {
     pub updated: Vec<InstanceUpdate>,
 }
 
+impl<'a> SubscribeMessage<'a> {
+    pub(crate) fn from_patch_update(tree: &'a RojoTree, patch: AppliedPatchSet) -> Self {
+        let removed = patch.removed;
+
+        let mut added = HashMap::new();
+        for id in patch.added {
+            let instance = tree.get_instance(id).unwrap();
+            added.insert(id, Instance::from_rojo_instance(instance));
+
+            for instance in tree.descendants(id) {
+                added.insert(instance.id(), Instance::from_rojo_instance(instance));
+            }
+        }
+
+        let updated = patch
+            .updated
+            .into_iter()
+            .map(|update| {
+                let changed_metadata = update
+                    .changed_metadata
+                    .as_ref()
+                    .map(InstanceMetadata::from_rojo_metadata);
+
+                let changed_properties = update
+                    .changed_properties
+                    .into_iter()
+                    .filter(|(_key, value)| property_filter(value.as_ref()))
+                    .collect();
+
+                InstanceUpdate {
+                    id: update.id,
+                    changed_name: update.changed_name,
+                    changed_class_name: update.changed_class_name,
+                    changed_properties,
+                    changed_metadata,
+                }
+            })
+            .collect();
+
+        Self {
+            removed,
+            added,
+            updated,
+        }
+    }
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct InstanceUpdate {
@@ -75,14 +124,8 @@ impl<'a> Instance<'a> {
         let properties = source
             .properties()
             .iter()
-            .filter_map(|(key, value)| {
-                // SharedString values can't be serialized via Serde
-                if matches!(value, Variant::SharedString(_)) {
-                    return None;
-                }
-
-                Some((key.clone(), Cow::Borrowed(value)))
-            })
+            .filter(|(_key, value)| property_filter(Some(value)))
+            .map(|(key, value)| (key.clone(), Cow::Borrowed(value)))
             .collect();
 
         Instance {
@@ -97,6 +140,18 @@ impl<'a> Instance<'a> {
     }
 }
 
+fn property_filter(value: Option<&Variant>) -> bool {
+    let ty = value.map(|value| value.ty());
+
+    // Lua can't do anything with SharedString values. They also can't be
+    // serialized directly by Serde!
+    if ty == Some(VariantType::SharedString) {
+        return false;
+    }
+
+    return true;
+}
+
 /// Response body from /api/rojo
 #[derive(Debug, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]

test-projects/weldconstraint/default.project.json

@@ -1,12 +0,0 @@
-{
-  "name": "weldconstraint",
-  "tree": {
-    "$className": "DataModel",
-
-    "Workspace": {
-      "Parts": {
-        "$path": "two-parts-welded.rbxmx"
-      }
-    }
-  }
-}

testez.toml

@@ -0,0 +1,66 @@
+[[afterAll.args]]
+type = "function"
+
+[[afterEach.args]]
+type = "function"
+
+[[beforeAll.args]]
+type = "function"
+
+[[beforeEach.args]]
+type = "function"
+
+[[describe.args]]
+type = "string"
+
+[[describe.args]]
+type = "function"
+
+[[describeFOCUS.args]]
+type = "string"
+
+[[describeFOCUS.args]]
+type = "function"
+
+[[describeSKIP.args]]
+type = "string"
+
+[[describeSKIP.args]]
+type = "function"
+
+[[expect.args]]
+type = "any"
+
+[[FIXME.args]]
+type = "string"
+required = false
+
+[FOCUS]
+args = []
+
+[[it.args]]
+type = "string"
+
+[[it.args]]
+type = "function"
+
+[[itFIXME.args]]
+type = "string"
+
+[[itFIXME.args]]
+type = "function"
+
+[[itFOCUS.args]]
+type = "string"
+
+[[itFOCUS.args]]
+type = "function"
+
+[[itSKIP.args]]
+type = "string"
+
+[[itSKIP.args]]
+type = "function"
+
+[SKIP]
+args = []

tests/rojo_test/io_util.rs

@@ -1,5 +1,6 @@
 use std::{
-    fs, io,
+    fs,
+    io::{self, Read},
     path::{Path, PathBuf},
     process::Child,
 };
@@ -50,5 +51,17 @@ pub struct KillOnDrop(pub Child);
 impl Drop for KillOnDrop {
     fn drop(&mut self) {
         let _ = self.0.kill();
+
+        if let Some(mut stdout) = self.0.stdout.take() {
+            let mut output = Vec::new();
+            let _ = stdout.read_to_end(&mut output);
+            print!("{}", String::from_utf8_lossy(&output));
+        }
+
+        if let Some(mut stderr) = self.0.stderr.take() {
+            let mut output = Vec::new();
+            let _ = stderr.read_to_end(&mut output);
+            eprint!("{}", String::from_utf8_lossy(&output));
+        }
     }
 }

tests/tests/build.rs

@@ -41,6 +41,9 @@ gen_build_tests! {
     json_model_legacy_name,
     module_in_folder,
     module_init,
+    project_composed_default,
+    project_composed_file,
+    project_root_name,
     rbxm_in_folder,
     rbxmx_in_folder,
     rbxmx_ref,
@@ -50,6 +53,8 @@ gen_build_tests! {
     txt,
     txt_in_folder,
     unresolved_values,
+    optional,
+    weldconstraint,
 }
 
 fn run_build_test(test_name: &str) {
@@ -60,7 +65,7 @@ fn run_build_test(test_name: &str) {
     let output_dir = tempdir().expect("couldn't create temporary directory");
     let output_path = output_dir.path().join(format!("{}.rbxmx", test_name));
 
-    let status = Command::new(ROJO_PATH)
+    let output = Command::new(ROJO_PATH)
         .args(&[
             "build",
             input_path.to_str().unwrap(),
@@ -69,10 +74,13 @@ fn run_build_test(test_name: &str) {
         ])
         .env("RUST_LOG", "error")
         .current_dir(working_dir)
-        .status()
+        .output()
         .expect("Couldn't start Rojo");
 
-    assert!(status.success(), "Rojo did not exit successfully");
+    print!("{}", String::from_utf8_lossy(&output.stdout));
+    eprint!("{}", String::from_utf8_lossy(&output.stderr));
+
+    assert!(output.status.success(), "Rojo did not exit successfully");
 
     let contents = fs::read_to_string(&output_path).expect("Couldn't read output file");
 

tests/tests/serve.rs

@@ -220,3 +220,34 @@ fn empty_json_model() {
         );
     });
 }
+
+#[test]
+#[ignore = "Rojo does not watch missing, optional files for changes."]
+fn add_optional_folder() {
+    run_serve_test("add_optional_folder", |session, mut redactions| {
+        let info = session.get_api_rojo().unwrap();
+        let root_id = info.root_instance_id;
+
+        assert_yaml_snapshot!("add_optional_folder", redactions.redacted_yaml(info));
+
+        let read_response = session.get_api_read(root_id).unwrap();
+        assert_yaml_snapshot!(
+            "add_optional_folder_all",
+            read_response.intern_and_redact(&mut redactions, root_id)
+        );
+
+        fs::create_dir(session.path().join("create-later")).unwrap();
+
+        let subscribe_response = session.get_api_subscribe(0).unwrap();
+        assert_yaml_snapshot!(
+            "add_optional_folder_subscribe",
+            subscribe_response.intern_and_redact(&mut redactions, ())
+        );
+
+        let read_response = session.get_api_read(root_id).unwrap();
+        assert_yaml_snapshot!(
+            "add_optional_folder_all-2",
+            read_response.intern_and_redact(&mut redactions, root_id)
+        );
+    });
+}