fix: memory leak in mainThreadDocumentsAndEditors

[Simon Siefke (SimonSiefke)]

Details

When restarting extensions, MainThreadDocumentsAndEditors left active MainThreadTextEditor wrappers subscribed to CodeEditorWidget events after their extension-host customer was disposed.

Change

The main change is just this one line of code, changing _textEditors from a Map to a DisposableMap:

private readonly _textEditors = new Map<string, MainThreadTextEditor>();

⬇️

private readonly _textEditors = this._register(new DisposableMap<string, MainThreadTextEditor>());

The other changes in the pr aren't necessarily needed. It's only to refactor the code a bit, using extends Disposable instead of this.toDispose.add.

Before

When restarting extensions 37 times, MainThreadTextEditor instances and their editor event callbacks grow:

After

No more matching MainThreadTextEditor callback growth is detected.

Test Video

extensions-restart-7-runs.mp4

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR ensures MainThreadDocumentsAndEditors properly cleans up registered editor listeners by adopting the standard Disposable pattern, and adds a regression test to confirm editor option-change listeners are removed on dispose.

Changes:

• Refactor MainThreadDocumentsAndEditors to extend Disposable and use _register(...) for lifecycle management.
• Replace the internal editor map with a DisposableMap so tracked editors are disposed automatically.
• Add a browser test asserting editor-property change listeners stop firing after disposal.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/vs/workbench/api/test/browser/mainThreadDocumentsAndEditors.test.ts	Adds a regression test and wiring to count editor property-change notifications.
src/vs/workbench/api/browser/mainThreadDocumentsAndEditors.ts	Refactors disposal/lifecycle management to ensure editor listeners/resources are released.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Dmitriy Vasyura (dmitrivMS)]

This does not compile...

[Simon Siefke (SimonSiefke)]

• fixed tsc errors.

[Copilot]

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0 new
• Review effort level: Balanced