Unloading the plugin fails, requiring restart

[opwvhk]

Description
There are several crash reports, which seem to point to one of several root causes:

• AvroIdlLanguage, or a class that depends on it, fails to initialise for some unknown reason
• AvroIdlLanguage fails to initialise because "Language with ID 'Avro IDL' is already registered",
  and the conflicting plugin is this plugin
• "Duplicate registration for EP opwvhk.avro.idl.naming.convention" by this plugin

All of these seem to be caused by not fully unloading the plugin.

Immediate cause: some JNI object keeps various plugin classes in memory

Root cause: unknown

To Reproduce

Sadly, the crashes cannot be reproduced.

The unloading failure can, but the logs (where IntelliJ analyses which GC root keeps the plugin in memory) point to JNI holding the classes in memory. The underlying culprit remains unidentified.

Expected behavior

The plugin should be unloaded quickly and properly.

Context:

• JetBrains Products: IntelliJ IDEA 2022.2.3 to (at least) 2024.2
• Plugin Versions: at least since 2021.3
• OS: all reports came from MacOS

[opwvhk]

The latest unload failing log shows:

Root 1:
  ROOT: Global JNI
  (root): javax.swing.TransferHandler$SwingDropTarget
  dtListener: javax.swing.TransferHandler$DropHandler
  support: javax.swing.TransferHandler$TransferSupport
  component: com.intellij.openapi.editor.impl.EditorComponentImpl
  editor: com.intellij.openapi.editor.impl.EditorImpl
  myProject: com.intellij.openapi.project.impl.ProjectImpl
  extensionArea: com.intellij.openapi.extensions.impl.ExtensionsAreaImpl
  extensionPoints: java.util.HashMap
  table: java.util.HashMap$Node[]
  []: java.util.HashMap$Node
  value: com.intellij.openapi.extensions.impl.InterfaceExtensionPoint
  cachedExtensions: java.util.ImmutableCollections$ListN
  elements: java.lang.Object[]
  []: opwvhk.intellij.avro_idl.editor.AvroIdlTreeStructureProvider
  <class>: java.lang.Class
* name: com.intellij.ide.plugins.cl.PluginClassLoader

This means an IntelliJ class is holding on to the plugin AvroIdlTreeStructureProvider...