IntelliJ Platform Plugin SDK Help

Dynamic Plugins

Installing, updating, and uninstalling plugins without restarting the IDE is available in the IntelliJ Platform.

During plugin development, Auto-Reload also allows code changes to take effect immediately in the sandbox IDE instance. To test whether dynamic installation works correctly, verify installing local build distribution succeeds (see Troubleshooting).

Note that any unloading problems in a production environment will ask the user to restart the IDE.

Restrictions

For a plugin to support this, all restrictions listed below must be met. To verify a plugin locally, invoke Code | Analyze Code | Run Inspection by Nameā€¦ and run Plugin DevKit | Plugin descriptor | Plugin.xml dynamic plugin verification inspection on all plugin descriptor files.

For plugins hosted on the JetBrains Marketplace, the built-in Plugin Verifier will run these checks automatically. See Plugin Verifier for more information on how to run it locally or on CI.

No Use of Components

No Components must be used; existing ones must be migrated to services, extensions, or listeners.

Action Group Requires ID

All <group> elements must declare a unique id.

Use Only Dynamic Extensions

Whether defined in the platform itself (IntelliJ Platform Extension Point and Listener List) or coming from other plugins, all used extension points must be marked explicitly as dynamic (see next paragraph).

Some deprecated extension points (for example, com.intellij.configurationProducer) are intentionally non-dynamic, and their usage should be migrated to the corresponding replacement.

Mark Extension Points as Dynamic

If a plugin defines its own custom extension points, they must adhere to specific usage rules and then be declared ready for dynamic use explicitly.

Configurables Depending on Extension Points

Any Configurable which depends on dynamic extension points must implement Configurable.WithEpDependencies.

No Use of Service Overrides

Application, project, and module services declared with overrides="true" aren't allowed.

Code

CachedValue

Loading/Unloading a plugin clears all cached values created using CachedValuesManager.

Do Not Store PSI

Do not store references to PSI elements in objects which can survive plugin loading or unloading; use SmartPsiElementPointer instead.

Do not Use FileType/Language as Map Key

Replace with String from Language.getID()/FileType.getName() (use inspection Plugin DevKit | Code | Map key may leak).

Plugin Load/Unload Events

Register DynamicPluginListener application listener to receive updates on plugin load/unload events.

This can be used to, for example:

  • cancel long-running activities or disallow unloading due to ongoing processes

  • clearing data from UserDataHolder objects (see clearInjectorCache() and dropFileCaches() in InjectedLanguageManagerImpl)

  • and similar cases

Resource Cleanup

Use Services implementing Disposable and perform cleanup in Disposable.dispose().

Troubleshooting

When a plugin is being uninstalled or updated, the IDE waits synchronously for the plugin unload and asks for restart if the unloading failed.

If it fails:

  1. Try a newer version of the IDE (eventually latest available from Early Access Program), in some cases platform bugs might be an issue. See this list of known platform issues related to handling dynamic plugins.

  2. Try in a fresh and new configuration (for example, clean the sandbox or use a different configuration directory).

Logging

All events are tracked under the com.intellij.ide.plugins.DynamicPlugins category in the IDE log file. If a plugin fails to reload, the log will contain a cause as to why.

Diagnosing Leaks

Finding leaks preventing unload

  1. Verify that the IDE is running with the VM parameter -XX:+UnlockDiagnosticVMOptions. When using Gradle, specify runIde.jvmArgs += "-XX:+UnlockDiagnosticVMOptions" otherwise Configure JVM Options.

  2. Set Registry key ide.plugins.snapshot.on.unload.fail to true (Go to Navigate | Search Everywhere and type Registry).

  3. Trigger the plugin reload.

  4. Open the .hprof memory snapshot generated in the user home directory on plugin unloading, look for the plugin ID string. IntelliJ Ultimate can open memory snapshots directly.

  5. Find the PluginClassLoader referencing the plugin ID string

  6. Look at references to the PluginClassLoader instance.

  7. Every one of them is a memory leak (or part of a memory leak) that needs to be resolved.

    When steps 1 and 2 are completed, the log will contain more information about the memory leak. For example, the following shows a chain of field references that is keeping the class loader in memory:

    2020-12-26 14:43:24,563 [ 251086] INFO - lij.ide.plugins.DynamicPlugins - Snapshot analysis result: Root 1: ROOT: Global JNI sun.awt.X11.XInputMethod.clientComponentWindow com.intellij.openapi.wm.impl.IdeFrameImpl.rootPane com.intellij.openapi.wm.impl.IdeRootPane.myToolbar com.intellij.openapi.actionSystem.impl.ActionToolbarImpl.myVisibleActions java.util.ArrayList.elementData java.lang.Object[] com.example.ActionExample.<class> com.example.ActionExample.<loader> * com.intellij.ide.plugins.cl.PluginClassLoader
    Last modified: 22 July 2024