[Bug]: Add-on JavaScript context not cleaned up when removing an add-on.

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
42/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Quiet
Tech stack
java, javascript
Domain
desktop, game-dev

Research direction

Start from the stack in AddOnLibrary.java (callMTSFunction / onInit eval) and the remove-library path under File > Add On Libraries. Trace how addon JS namespaces and Graal/polyglot contexts are created versus torn down so leftover namespaces (data.listNamespaces("addon:")) and const redefinition errors go away. Done when removing a library clears its context and re-adding the same add-on works without ParserException.

Written by the indexing model from the issue text.

Description

bug
Describe the Bug

When an add-on is installed in a campaign, a new context is created within which the add-on's JavaScript can executed. When the add-on is removed, this context remains. Adding the same add-on again can then cause errors (e.g.,, if the same variables gets defined) or fail for logical reasons if old state is used.

To Reproduce
  1. Download this example add-on: collision-example.mtlib
  2. Drag the add-on into a blank campaign.
  3. Open File > Add On Libraries ..., select the add-on and click Remove Library.
    • Notice that typing [r: data.listNamespaces("addon:")] in the chat window results in the add-on namespace still be visible.
  4. Drag the add-on into the campaign again.
  5. Notice the error that gets presented.

The key detail in the attached add-on is that it evals this line during onInit:

const namespace = 'com.kwvanderlinde.collision';

The display of the error is not 100% consistent, so you may have to repeat steps (3) & (4) a couple times.

Expected Behaviour

When an add-on is removed, all of its state is also removed (namespace and associated context). It should be possible to add the add-on again to the same campaign without issue (unless the add-on itself is at fault for doing something very bad).

Screenshots

No response

MapTool Info

1.18.6

Desktop

Linux Mint 22.1

Additional Context

Here is the error:

java.util.concurrent.CompletionException: net.rptools.parser.ParserException: com.oracle.truffle.polyglot.PolyglotEngineException error executing expression js.evalURI("com.kwvanderlinde.collision", "lib://com.kwvanderlinde.collision/example.js").
	at net.rptools.maptool.model.library.addon.AddOnLibrary.lambda$callMTSFunction$15(AddOnLibrary.java:672)
	at java.desktop/java.awt.event.InvocationEvent.dispatch(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at net.rptools.maptool.client.swing.MapToolEventQueue.dispatchEvent(MapToolEventQueue.java:63)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.WaitDispatchSupport$2.run(Unknown Source)
	at java.desktop/java.awt.WaitDispatchSupport$4.run(Unknown Source)
	at java.desktop/java.awt.WaitDispatchSupport$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at java.desktop/java.awt.WaitDispatchSupport.enter(Unknown Source)
	at java.desktop/java.awt.Dialog.show(Unknown Source)
	at java.desktop/javax.swing.JOptionPane.showOptionDialog(Unknown Source)
	at java.desktop/javax.swing.JOptionPane.showMessageDialog(Unknown Source)
	at java.desktop/javax.swing.JOptionPane.showMessageDialog(Unknown Source)
	at net.rptools.maptool.client.MapTool.showMessage(MapTool.java:257)
	at net.rptools.maptool.client.MapTool.showInformation(MapTool.java:380)
	at net.rptools.maptool.client.MapTool.showInformation(MapTool.java:363)
	at net.rptools.maptool.client.TransferableHelper.lambda$importData$1(TransferableHelper.java:566)
	at java.desktop/java.awt.event.InvocationEvent.dispatch(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at net.rptools.maptool.client.swing.MapToolEventQueue.dispatchEvent(MapToolEventQueue.java:63)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)
Caused by: net.rptools.parser.ParserException: com.oracle.truffle.polyglot.PolyglotEngineException error executing expression js.evalURI("com.kwvanderlinde.collision", "lib://com.kwvanderlinde.collision/example.js").
	at net.rptools.maptool.client.MapToolLineParser.parseExpression(MapToolLineParser.java:1124)
	at net.rptools.maptool.client.MapToolLineParser.parseLine(MapToolLineParser.java:857)
	at net.rptools.maptool.client.MapToolLineParser.runMacroBlock(MapToolLineParser.java:1456)
	at net.rptools.maptool.client.MapToolLineParser.runMacro(MapToolLineParser.java:1380)
	at net.rptools.maptool.client.MapToolLineParser.runMacro(MapToolLineParser.java:1177)
	at net.rptools.maptool.model.library.addon.AddOnLibrary.lambda$callMTSFunction$15(AddOnLibrary.java:670)
	... 38 more
Dominant language
Java
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Forks
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Avg merge
3d 17h
Merged PRs (30d)
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