Fix 'Open Scripts Externally' crashing studio.

Closes #369.

CHANGELOG.md

@@ -4,9 +4,11 @@
 * 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. 
-* Fixed `Name` and `Parent` properties being allowed in Rojo projects. ([#413](pr-413))
 * 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])
 
+[issue-369]: https://github.com/rojo-rbx/rojo/issues/369
 [pr-413]: https://github.com/rojo-rbx/rojo/pull/413
 
 ## [7.0.0-alpha.3][7.0.0-alpha.3] (February 19, 2021)

plugin/src/ServeSession.lua

@@ -1,4 +1,5 @@
 local StudioService = game:GetService("StudioService")
+local RunService = game:GetService("RunService")
 
 local Log = require(script.Parent.Parent.Log)
 local Fmt = require(script.Parent.Parent.Fmt)
@@ -161,10 +162,18 @@ function ServeSession:__onActiveScriptChanged(activeScript)
 
 	Log.debug("Trying to open script {} externally...", activeScript)
 
-	-- Force-close the script inside Studio
-	local existingParent = activeScript.Parent
-	activeScript.Parent = nil
-	activeScript.Parent = existingParent
+	-- Force-close the script inside Studio... with a small delay in the middle
+	-- to prevent Studio from crashing.
+	spawn(function()
+		local existingParent = activeScript.Parent
+		activeScript.Parent = nil
+
+		for i = 1, 3 do
+			RunService.Heartbeat:Wait()
+		end
+
+		activeScript.Parent = existingParent
+	end)
 
 	-- Notify the Rojo server to open this script
 	self.__apiContext:open(scriptId)