Bug Fix

What was the bug?

Review threads were rendered twice in PR diff editors after VS Code restart on some machines: two vscode.CommentThread widgets appeared for the same review thread on the same line.

How did you fix it?

The onDidChangeReviewThreads handlers in both comment controllers create a new VS Code comment thread when an added event arrives that doesn't match any pending thread. They never checked whether a thread with that gitHubThreadId was already present in their cache, so any race between addThreadsForEditors / doInitializeCommentThreads (which seeds threads from pullRequestModel.reviewThreadsCache) and a concurrent added event for the same thread produced a duplicate widget.

• PullRequestCommentController.onDidChangeReviewThreads: before falling through to pending-match / editor-match creation, look up the cache by gitHubThreadId; if found, route through updateThread and continue.
• ReviewCommentController.onDidChangeReviewThreads: same guard, reusing the existing _findMatchingThread helper that already searches the workspace / review-scheme / obsolete maps.
• Drive-by: the early-exit when no matching open editor was found used return, aborting the rest of the added loop and the entire changed / removed processing for that event. Changed to continue.

// PullRequestCommentController.onDidChangeReviewThreads
for (const thread of e.added) {
    const key = this.getCommentThreadCacheKey(thread.path, thread.diffSide === DiffSide.LEFT);

    const existing = this._commentThreadCache[key]?.find(t => t.gitHubThreadId === thread.id);
    if (existing) {
        updateThread(this._context, existing, thread, this._githubRepositories);
        continue;
    }
    // ...pending-match / create-from-editor as before
}