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>

CHANGELOG.md

@@ -2,6 +2,22 @@
 
 ## Unreleased Changes
 
+## [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.
@@ -87,7 +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])

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rojo"
-version = "7.0.0"
+version = "7.1.0"
 authors = ["Lucien Greathouse <me@lpghatguy.com>"]
 description = "Enables professional-grade development tools for Roblox developers"
 license = "MPL-2.0"

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

@@ -14,8 +14,6 @@ local PORT_WIDTH = 74
 local DIVIDER_WIDTH = 1
 local HOST_OFFSET = 12
 
-local lastHost, lastPort
-
 local e = Roact.createElement
 
 local function AddressEntry(props)
@@ -26,7 +24,7 @@ local function AddressEntry(props)
 			layoutOrder = props.layoutOrder,
 		}, {
 			Host = e("TextBox", {
-				Text = lastHost or "",
+				Text = props.host or "",
 				Font = Enum.Font.Code,
 				TextSize = 18,
 				TextColor3 = theme.AddressEntry.TextColor,
@@ -34,6 +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),
@@ -41,17 +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 = lastPort or "",
+				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),
@@ -60,12 +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", {
@@ -82,11 +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, {
@@ -95,8 +96,10 @@ function NotConnectedPage:render()
 		}),
 
 		AddressEntry = e(AddressEntry, {
-			hostRef = self.hostRef,
+			host = self.props.host,
-			portRef = self.portRef,
+			port = self.props.port,
+			onHostChange = self.props.onHostChange,
+			onPortChange = self.props.onPortChange,
 			transparency = self.props.transparency,
 			layoutOrder = 2,
 		}),
@@ -119,18 +122,7 @@ function NotConnectedPage:render()
 				style = "Solid",
 				transparency = self.props.transparency,
 				layoutOrder = 2,
-				onClick = function()
+				onClick = self.props.onConnect,
-					local hostText = self.hostRef.current.Text
-					local portText = self.portRef.current.Text
-
-					lastHost = hostText
-					lastPort = portText
-
-					self.props.onConnect(
-						#hostText > 0 and hostText or Config.defaultHost,
-						#portText > 0 and portText or Config.defaultPort
-					)
-				end,
 			}),
 
 			Layout = e("UIListLayout", {

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)
+					NotConnectedPage = createPageElement(AppStatus.NotConnected, {
-						return createPageElement(AppStatus.NotConnected, {
+						host = self.host,
-							onConnect = function(host, port)
+						onHostChange = self.setHost,
-								self:startSession(host, port, {
+						port = self.port,
-									openScriptsExternally = settings:get("openScriptsExternally"),
+						onPortChange = self.setPort,
-									twoWaySync = settings:get("twoWaySync"),
-								})
-							end,
 
-							onNavigateSettings = function()
+						onConnect = function()
-								self:setState({
+							self:startSession()
-									appStatus = AppStatus.Settings,
+						end,
-								})
+
-							end,
+						onNavigateSettings = function()
-						})
+							self:setState({
-					end),
+								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:endSession()
-
-							self.serveSession:stop()
-							self.serveSession = nil
-							self:setState({
-								appStatus = AppStatus.NotConnected,
-							})
-
-							Log.trace("Session terminated by user")
 						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/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},
+	version = {7, 1, 0},
 	expectedServerVersionString = "7.0 or newer",
 	protocolVersion = 4,
 	defaultHost = "localhost",

plugin/src/ServeSession.lua

@@ -113,6 +113,10 @@ function ServeSession:__fmtDebug(output)
 	output:write("}")
 end
 
+function ServeSession:getStatus()
+	return self.__status
+end
+
 function ServeSession:onStatusChanged(callback)
 	self.__statusChangedCallback = callback
 end

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-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/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(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;
-                    }
                     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(snapshot) => snapshot,
-                Ok(None) => {
-                    log::error!("Snapshot did not return an instance from a project node.");
-                    log::error!("This is a bug!");
-                    return None;
-                }
                 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(
+    #[serde(rename = "$path", skip_serializing_if = "Option::is_none")]
-        rename = "$path",
+    pub path: Option<PathNode>,
-        serialize_with = "crate::path_serializer::serialize_option_absolute",
-        skip_serializing_if = "Option::is_none"
-    )]
-    pub path: Option<PathBuf>,
 }
 
 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/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)?
+        let snapshot = snapshot_from_vfs(&instance_context, &vfs, &start_path)?;
-            .expect("snapshot did not return an instance");
 
         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
+        compute_patch_set_internal(&mut context, snapshot, tree, id, &mut patch_set);
-    // for all of the IDs that we know about so far.
+
-    rewrite_refs_in_updates(&context, &mut patch_set.updated_instances);
+        // Rewrite Ref properties to refer to instance IDs instead of snapshot IDs
-    rewrite_refs_in_additions(&context, &mut patch_set.added_instances);
+        // 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/project.rs

@@ -5,7 +5,7 @@ use memofs::Vfs;
 use rbx_reflection::ClassTag;
 
 use crate::{
-    project::{Project, ProjectNode},
+    project::{PathNode, Project, ProjectNode},
     snapshot::{
         InstanceContext, InstanceMetadata, InstanceSnapshot, InstigatingSource, PathIgnoreRule,
     },
@@ -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
+    match snapshot_project_node(&context, path, &project.name, &project.tree, vfs, None)? {
-    // understand, this may panic!
+        Some(found_snapshot) => {
-    let mut snapshot =
+            let mut snapshot = found_snapshot;
-        snapshot_project_node(&context, path, &project.name, &project.tree, vfs, None)?.unwrap();
+            // 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
+            // Mark this snapshot (the root node of the project file) as being
-    // coarse.
+            // related to the project file.
-    //
+            //
-    // Ideally, we'd only snapshot the project file if the project file
+            // We SHOULD NOT mark the project file as a relevant path for any
-    // actually changed. Because Rojo only has the concept of one
+            // nodes that aren't roots. They'll be updated as part of the project
-    // relevant path -> snapshot path mapping per instance, we pick the more
+            // file being updated.
-    // conservative approach of snapshotting the project file if any
+            snapshot.metadata.relevant_paths.push(path.to_path_buf());
-    // 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
+            Ok(Some(snapshot))
-    // related to the project file.
+        }
-    //
+        None => Ok(None),
-    // 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))
 }
 
 pub fn snapshot_project_node(
@@ -77,7 +78,9 @@ 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 full_path = if path.is_relative() {
@@ -106,16 +109,6 @@ pub fn snapshot_project_node(
             // Take the snapshot's metadata as-is, which will be mutated later
             // on.
             metadata = snapshot.metadata;
-        } else {
-            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(),
-            );
         }
     }
 
@@ -125,20 +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,
+        (Some(project), None, None, _) => project,
-        (None, Some(path), None) => path,
+        (None, Some(path), None, _) => path,
-        (None, None, Some(inference)) => inference,
+        (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 {
@@ -146,7 +140,7 @@ pub fn snapshot_project_node(
             }
         }
 
-        (Some(project), Some(path), _) => {
+        (Some(project), Some(path), _, _) => {
             if path == "Folder" {
                 project
             } else {
@@ -160,12 +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\

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/tests/build.rs

@@ -53,6 +53,7 @@ gen_build_tests! {
     txt,
     txt_in_folder,
     unresolved_values,
+    optional,
     weldconstraint,
 }
 

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)
+        );
+    });
+}