Remember last active chat per session across restarts

[sandy081]

Persist per-session state (ISessionState) in the sessions management service so that when a session is reopened, the last active chat is restored instead of always defaulting to the first chat.

Changes

• Add ISessionState interface with sessionResource, activeChatResource, and isActive fields
• Store session states as a JSON array, load into a ResourceMap keyed by session resource URI
• Restore last active chat in setActiveSession() when switching sessions
• Track active chat changes via autorun to keep persisted state current
• Mark the currently active session with isActive flag for use on reload
• Remove legacy lastSelectedSession / LAST_SELECTED_SESSION_KEY storage (consolidated into the new session state)

[github-actions]

Screenshot Changes

Base: f8d07504 Current: 0d80cc67

Changed (2)

chat/aiCustomizations/aiCustomizationManagementEditor/McpBrowseMode/Light

Before	After

editor/inlineCompletions/other/JumpToHint/Dark

Before	After

[Copilot]

Pull request overview

This PR adds persistence for per-session UI state in the Sessions window so that reopening a session restores the previously active chat (instead of always defaulting to the first chat), and consolidates prior “last selected session” storage into a session-state store.

Changes:

• Introduces ISessionState and persists session states as JSON in workspace storage, loaded into a ResourceMap.
• Restores a session’s last active chat when activating/opening that session.
• Tracks active chat changes via autorun and persists activeChatResource (and an isActive marker).

Show a summary per file

File	Description
src/vs/sessions/services/sessions/browser/sessionsManagementService.ts	Adds persisted per-session state loading/saving and restores last active chat when reopening sessions.

Copilot's findings

Comments suppressed due to low confidence (3)

src/vs/sessions/services/sessions/browser/sessionsManagementService.ts:462

• In the persistence autorun, chat.status.read(undefined) is not tracked by the autorun (and won’t re-run when the chat transitions from Untitled to a real status). This means a chat that starts untitled may never get persisted as the last active chat even after it becomes titled. Use chat.status.read(reader) (or a separate reaction that watches the status) so the state is updated once the chat becomes non-untitled.

			this._activeSessionDisposables.add(autorun(reader => {
				const chat = activeChatObs.read(reader);
				if (chat && chat.status.read(undefined) !== SessionStatus.Untitled) {
					// Mark all sessions as inactive, then set this one as active

src/vs/sessions/services/sessions/browser/sessionsManagementService.ts:504

• _saveSessionStates persists every entry currently in _sessionStates, but entries are never removed when sessions are deleted/removed. Over time this can grow unbounded in workspace storage and keep restoring state for sessions that no longer exist. Consider pruning _sessionStates (e.g., keep only keys that still exist in getSessions() / remove on e.removed) before writing to storage.

	private _saveSessionStates(): void {
		const entries: ISessionState[] = [];
		for (const [, state] of this._sessionStates) {
			entries.push(state);
		}
		this.storageService.store(ACTIVE_SESSION_STATES_KEY, JSON.stringify(entries), StorageScope.WORKSPACE, StorageTarget.MACHINE);

src/vs/sessions/services/sessions/browser/sessionsManagementService.ts:483

• _sessionStates is created with the default ResourceMap keying (uri.toString()), which is case-sensitive and can fail to match the same logical resource on platforms with case-insensitive paths or different URI normalizations. Consider constructing the ResourceMap with uri => this.uriIdentityService.extUri.getComparisonKey(uri) so lookups like this._sessionStates.get(session.resource) are stable across restarts and OSes.

	private _loadSessionStates(): ResourceMap<ISessionState> {
		const map = new ResourceMap<ISessionState>();
		const raw = this.storageService.get(ACTIVE_SESSION_STATES_KEY, StorageScope.WORKSPACE);

• Files reviewed: 1/1 changed files
• Comments generated: 1