Add archived state management and worktree sharing for chat sessions

extensions/copilot/src/extension/chatSessions/common/chatSessionMetadataStore.ts

@@ -105,6 +105,12 @@ export interface ChatSessionMetadataFile {
 	 * session or if the session is a child session created from the Agents app.
 	 */
 	parentSessionId?: string;
+	/**
+	 * Whether the session is currently archived. Tracked here so worktree-sharing
+	 * checks can ignore archived siblings (whose worktrees are reconstructed on
+	 * un-archive via {@link IChatSessionWorktreeService.recreateWorktreeOnUnarchive}).
+	 */
+	archived?: boolean;
 	/** Milliseconds since epoch when this metadata was first written. */
 	created?: number;
 	/** Milliseconds since epoch of the last write. Used for top-N trim sort and cross-process merge. */
@@ -152,7 +158,19 @@ export interface IChatSessionMetadataStore {
 	setSessionOrigin(sessionId: string): Promise<void>;
 	getSessionOrigin(sessionId: string): Promise<'vscode' | 'other'>;
 	setSessionParentId(sessionId: string, parentSessionId: string): Promise<void>;
-	getSessionParentId(sessionId: string): Promise<string | undefined>;
+	/**
+	 * Returns the parent lineage info for a session, distinguishing forked sessions
+	 * (created via the fork action) from sub-sessions (spawned by a parent session
+	 * to do work on its behalf). Returns `undefined` for top-level sessions with no
+	 * stored parent.
+	 */
+	getSessionParentId(sessionId: string): Promise<{ parentSessionId: string; kind: 'forked' | 'sub-session' } | undefined>;
+	/**
+	 * Persist the archived state of a session. Called from the chat session item state
+	 * change handler so worktree-sharing checks can later ignore archived siblings.
+	 */
+	setSessionArchived(sessionId: string, archived: boolean): Promise<void>;
+	getSessionArchived(sessionId: string): Promise<boolean>;
 	/**
 	 * Re-read the shared bulk metadata file from disk and merge into the in-memory cache.
 	 * Wired to the chat-sessions UI refresh action so cross-process writes become visible

extensions/copilot/src/extension/chatSessions/common/chatSessionWorkspaceFolderService.ts

@@ -75,4 +75,9 @@ export interface IChatSessionWorkspaceFolderService {
 	clearWorkspaceChanges(folderUri: vscode.Uri): string[];
 
 	hasCachedChanges(sessionId: string): Promise<boolean>;
+
+	/**
+	 * Returns the ids of sessions whose tracked workspace folder matches the given URI.
+	 */
+	getAssociatedSessions(folderUri: vscode.Uri): string[];
 }

extensions/copilot/src/extension/chatSessions/common/test/mockChatSessionMetadataStore.ts

@@ -149,10 +149,24 @@ export class MockChatSessionMetadataStore implements IChatSessionMetadataStore {
 		return Promise.resolve();
 	}
 
-	getSessionParentId(_sessionId: string): Promise<string | undefined> {
+	getSessionParentId(_sessionId: string): Promise<{ parentSessionId: string; kind: 'forked' | 'sub-session' } | undefined> {
 		return Promise.resolve(undefined);
 	}
 
+	private readonly _archived = new Set<string>();
+
+	async setSessionArchived(sessionId: string, archived: boolean): Promise<void> {
+		if (archived) {
+			this._archived.add(sessionId);
+		} else {
+			this._archived.delete(sessionId);
+		}
+	}
+
+	async getSessionArchived(sessionId: string): Promise<boolean> {
+		return this._archived.has(sessionId);
+	}
+
 	getSessionIdsForFolder(folder: vscode.Uri): string[] {
 		const folderPath = folder.fsPath;
 		const sessionIds: string[] = [];

extensions/copilot/src/extension/chatSessions/copilotcli/vscode-node/chatSessionMetadataStoreImpl.ts

@@ -393,6 +393,7 @@ export class ChatSessionMetadataStore extends Disposable implements IChatSession
 			parentSessionId: sourceSessionId,
 			origin: 'vscode',
 			kind: 'forked',
+			archived: false,
 		};
 		await this.updateMetadataFields(targetSessionId, forkedMetadata);
 	}
@@ -423,9 +424,22 @@ export class ChatSessionMetadataStore extends Disposable implements IChatSession
 		await this.updateMetadataFields(sessionId, { parentSessionId, kind: 'sub-session' });
 	}
 
-	public async getSessionParentId(sessionId: string): Promise<string | undefined> {
+	public async getSessionParentId(sessionId: string): Promise<{ parentSessionId: string; kind: 'forked' | 'sub-session' } | undefined> {
 		const metadata = await this.getSessionMetadata(sessionId, false);
-		return metadata?.parentSessionId;
+		if (!metadata?.parentSessionId || !metadata.kind) {
+			return undefined;
+		}
+		return { parentSessionId: metadata.parentSessionId, kind: metadata.kind };
+	}
+
+	public async setSessionArchived(sessionId: string, archived: boolean): Promise<void> {
+		await this._ready;
+		await this.updateMetadataFields(sessionId, { archived });
+	}
+
+	public async getSessionArchived(sessionId: string): Promise<boolean> {
+		const metadata = await this.getSessionMetadata(sessionId, false);
+		return metadata?.archived === true;
 	}
 
 	private async getSessionMetadata(sessionId: string, createMetadataFileIfNotFound = true): Promise<ChatSessionMetadataFile | undefined> {

extensions/copilot/src/extension/chatSessions/vscode-node/chatSessions.ts

@@ -73,6 +73,7 @@ import { ClaudeCustomizationProvider } from './claudeCustomizationProvider';
 import { CopilotCLIChatSessionInitializer, ICopilotCLIChatSessionInitializer } from '../copilotcli/vscode-node/copilotCLIChatSessionInitializer';
 import { CopilotCLIChatSessionContentProvider, CopilotCLIChatSessionParticipant, registerCLIChatCommands } from './copilotCLIChatSessions';
 import { CopilotCLIChatSessionContentProvider as CopilotCLIChatSessionContentProviderV1, CopilotCLIChatSessionItemProvider as CopilotCLIChatSessionItemProviderV1, CopilotCLIChatSessionParticipant as CopilotCLIChatSessionParticipantV1, registerCLIChatCommands as registerCLIChatCommandsV1 } from './copilotCLIChatSessionsContribution';
+import { getBlockingSiblingSessionsForFolder } from './worktreeSharing';
 import { CopilotCLICustomizationProvider } from '../copilotcli/vscode-node/copilotCLICustomizationProvider';
 import { CopilotCLITerminalIntegration, ICopilotCLITerminalIntegration } from './copilotCLITerminalIntegration';
 import { CopilotCloudSessionsProvider } from './copilotCloudSessionsProvider';
@@ -231,6 +232,7 @@ export class ChatSessionsContrib extends Disposable implements IExtensionContrib
 		const copilotModels = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(ICopilotCLIModels));
 		const copilotCLIFolderMruService = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatFolderMruService));
 		const pullRequestCreationService = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IPullRequestCreationService));
+		const sessionMetadata = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatSessionMetadataStore));
 
 		this._register(copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(ICopilotCLISessionTracker)));
 		this._register(copilotcliAgentInstaService.createInstance(CopilotCLIContrib));
@@ -241,10 +243,9 @@ export class ChatSessionsContrib extends Disposable implements IExtensionContrib
 		this._register(vscode.chat.registerChatSessionContentProvider(this.copilotcliSessionType, copilotcliChatSessionContentProvider, copilotcliParticipant));
 		const copilotcliCustomizationProvider = this._register(copilotcliAgentInstaService.createInstance(CopilotCLICustomizationProvider));
 		this._register(vscode.chat.registerChatSessionCustomizationProvider(this.copilotcliSessionType, CopilotCLICustomizationProvider.metadata, copilotcliCustomizationProvider));
-		this._register(registerCLIChatCommands(copilotCLISessionService, copilotCLIWorktreeManagerService, copilotCLIWorktreeCheckpointService, gitService, gitCommitMessageService, copilotCLIWorkspaceFolderSessions, copilotcliChatSessionContentProvider, folderRepositoryManager, copilotCLIFolderMruService, nativeEnvService, fileSystemService, sessionTracker, terminalIntegration, pullRequestCreationService, logService));
+		this._register(registerCLIChatCommands(copilotCLISessionService, copilotCLIWorktreeManagerService, copilotCLIWorktreeCheckpointService, gitService, gitCommitMessageService, copilotCLIWorkspaceFolderSessions, copilotcliChatSessionContentProvider, folderRepositoryManager, copilotCLIFolderMruService, nativeEnvService, fileSystemService, sessionTracker, terminalIntegration, pullRequestCreationService, sessionMetadata, logService));
 		// #endregion
 
-		const sessionMetadata = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatSessionMetadataStore));
 		return { sessionMetadata };
 	}
 
@@ -301,13 +302,32 @@ export class ChatSessionsContrib extends Disposable implements IExtensionContrib
 		const copilotCLISessionService = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(ICopilotCLISessionService));
 		const copilotCLIWorktreeManagerService = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatSessionWorktreeService));
 		const copilotCLIWorktreeCheckpointService = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatSessionWorktreeCheckpointService));
+		const copilotCLIWorkspaceFolderSessions = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatSessionWorkspaceFolderService));
+		const copilotCLIMetadataStore = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatSessionMetadataStore));
 
 		// Handle worktree cleanup/recreation when archive state changes
 		const onDidChangeChatSessionItemState = (providerRegistration as { onDidChangeChatSessionItemState?: vscode.Event<vscode.ChatSessionItem> }).onDidChangeChatSessionItemState;
 		if (onDidChangeChatSessionItemState) {
 			this._register(onDidChangeChatSessionItemState(async (item) => {
 				const sessionId = SessionIdForCLI.parse(item.resource);
+				// Persist archived state first so worktree-sharing checks (delete/archive)
+				// can ignore archived siblings — their worktrees are reconstructed on
+				// un-archive via `recreateWorktreeOnUnarchive`.
+				try {
+					await copilotCLIMetadataStore.setSessionArchived(sessionId, !!item.archived);
+				} catch (error) {
+					logService.error(`[CopilotCLI] Failed to persist archived state for session ${sessionId}:`, error);
+				}
 				if (item.archived) {
+					// Skip worktree cleanup if other live sessions still depend on this worktree.
+					const worktreePath = await copilotCLIWorktreeManagerService.getWorktreePath(sessionId);
+					if (worktreePath) {
+						const siblings = await getBlockingSiblingSessionsForFolder(worktreePath, sessionId, copilotCLIMetadataStore, copilotCLIWorkspaceFolderSessions);
+						if (siblings.length > 0) {
+							logService.trace(`[CopilotCLI] Skipping worktree cleanup for archived session ${sessionId}: ${siblings.length} other session(s) still use the worktree`);
+							return;
+						}
+					}
 					try {
 						const result = await copilotCLIWorktreeManagerService.cleanupWorktreeOnArchive(sessionId);
 						logService.trace(`[CopilotCLI] Worktree cleanup for session ${sessionId}: ${result.cleaned ? 'cleaned' : result.reason}`);
@@ -328,7 +348,6 @@ export class ChatSessionsContrib extends Disposable implements IExtensionContrib
 			}));
 		}
 
-		const copilotCLIWorkspaceFolderSessions = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatSessionWorkspaceFolderService));
 		const folderRepositoryManager = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IFolderRepositoryManager));
 		const nativeEnvService = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(INativeEnvService));
 		const fileSystemService = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IFileSystemService));
@@ -345,7 +364,7 @@ export class ChatSessionsContrib extends Disposable implements IExtensionContrib
 		this._register(vscode.chat.registerChatSessionContentProvider(this.copilotcliSessionType, copilotcliChatSessionContentProvider, copilotcliParticipant));
 		const copilotcliCustomizationProvider = this._register(copilotcliAgentInstaService.createInstance(CopilotCLICustomizationProvider));
 		this._register(vscode.chat.registerChatSessionCustomizationProvider(this.copilotcliSessionType, CopilotCLICustomizationProvider.metadata, copilotcliCustomizationProvider));
-		this._register(registerCLIChatCommandsV1(copilotcliSessionItemProvider, copilotCLISessionService, copilotCLIWorktreeManagerService, copilotCLIWorktreeCheckpointService, gitService, gitCommitMessageService, gitExtensionService, toolsService, copilotCLIWorkspaceFolderSessions, copilotcliChatSessionContentProvider, folderRepositoryManager, copilotFolderMruService, nativeEnvService, fileSystemService, pullRequestCreationService, logService));
+		this._register(registerCLIChatCommandsV1(copilotcliSessionItemProvider, copilotCLISessionService, copilotCLIWorktreeManagerService, copilotCLIWorktreeCheckpointService, gitService, gitCommitMessageService, gitExtensionService, toolsService, copilotCLIWorkspaceFolderSessions, copilotcliChatSessionContentProvider, folderRepositoryManager, copilotFolderMruService, nativeEnvService, fileSystemService, pullRequestCreationService, copilotCLIMetadataStore, logService));
 		// #endregion
 
 		const sessionMetadata = copilotcliAgentInstaService.invokeFunction(accessor => accessor.get(IChatSessionMetadataStore));

extensions/copilot/src/extension/chatSessions/vscode-node/copilotCLIChatSessions.ts

@@ -51,6 +51,7 @@ import { ICopilotCLITerminalIntegration, TerminalOpenLocation } from './copilotC
 import { CopilotCloudSessionsProvider } from './copilotCloudSessionsProvider';
 import { UNTRUSTED_FOLDER_MESSAGE } from './folderRepositoryManagerImpl';
 import { IPullRequestDetectionService } from './pullRequestDetectionService';
+import { getBlockingSiblingSessionsForFolder } from './worktreeSharing';
 import { getCopilotCLIModelDetails, persistCopilotCLIResponseModelId } from './copilotCLIModelDetails';
 import { getSelectedSessionOptions, ISessionOptionGroupBuilder, OPEN_REPOSITORY_COMMAND_ID, toRepositoryOptionItem, toWorkspaceFolderOptionItem } from './sessionOptionGroupBuilder';
 import { ISessionRequestLifecycle } from './sessionRequestLifecycle';
@@ -259,7 +260,24 @@ export class CopilotCLIChatSessionContentProvider extends Disposable implements
 		if (controller.onDidChangeChatSessionItemState) {
 			this._register(controller.onDidChangeChatSessionItemState(async (item) => {
 				const sessionId = SessionIdForCLI.parse(item.resource);
+				// Persist archived state first so worktree-sharing checks (delete/archive)
+				// can ignore archived siblings — their worktrees are reconstructed on
+				// un-archive via `recreateWorktreeOnUnarchive`.
+				try {
+					await this._metadataStore.setSessionArchived(sessionId, !!item.archived);
+				} catch (error) {
+					this.logService.error(`[CopilotCLI] Failed to persist archived state for session ${sessionId}:`, error);
+				}
 				if (item.archived) {
+					// Skip worktree cleanup if other live sessions still depend on this worktree.
+					const worktreePath = await this.copilotCLIWorktreeManagerService.getWorktreePath(sessionId);
+					if (worktreePath) {
+						const siblings = await getBlockingSiblingSessionsForFolder(worktreePath, sessionId, this._metadataStore, this._workspaceFolderService);
+						if (siblings.length > 0) {
+							this.logService.trace(`[CopilotCLI] Skipping worktree cleanup for archived session ${sessionId}: ${siblings.length} other session(s) still use the worktree`);
+							return;
+						}
+					}
 					try {
 						const result = await this.copilotCLIWorktreeManagerService.cleanupWorktreeOnArchive(sessionId);
 						this.logService.trace(`[CopilotCLI] Worktree cleanup for session ${sessionId}: ${result.cleaned ? 'cleaned' : result.reason}`);
@@ -479,7 +497,8 @@ export class CopilotCLIChatSessionContentProvider extends Disposable implements
 		workingDirectory: vscode.Uri | undefined,
 	): Promise<{ readonly [key: string]: unknown }> {
 		if (worktreeProperties) {
-			const sessionParentId = await this._metadataStore.getSessionParentId(sessionId);
+			const parentInfo = await this._metadataStore.getSessionParentId(sessionId);
+			const sessionParentId = parentInfo?.kind === 'sub-session' ? parentInfo.parentSessionId : undefined;
 
 			return {
 				sessionParentId,
@@ -531,11 +550,12 @@ export class CopilotCLIChatSessionContentProvider extends Disposable implements
 			} satisfies { readonly [key: string]: unknown };
 		}
 
-		const [sessionParentId, sessionRequestDetails, repositoryProperties] = await Promise.all([
+		const [parentInfo, sessionRequestDetails, repositoryProperties] = await Promise.all([
 			this._metadataStore.getSessionParentId(sessionId),
 			this._metadataStore.getRequestDetails(sessionId),
 			this._metadataStore.getRepositoryProperties(sessionId)
 		]);
+		const sessionParentId = parentInfo?.kind === 'sub-session' ? parentInfo.parentSessionId : undefined;
 
 		let lastCheckpointRef: string | undefined;
 		for (let i = sessionRequestDetails.length - 1; i >= 0; i--) {
@@ -1038,18 +1058,19 @@ export function registerCLIChatCommands(
 	sessionTracker: ICopilotCLISessionTracker,
 	terminalIntegration: ICopilotCLITerminalIntegration,
 	pullRequestCreationService: IPullRequestCreationService,
+	metadataStore: IChatSessionMetadataStore,
 	logService: ILogService
 ): IDisposable {
 	const disposableStore = new DisposableStore();
 
-	async function deleteSessionById(id: string): Promise<void> {
-		const worktree = await copilotCLIWorktreeManagerService.getWorktreeProperties(id);
-		const worktreePath = await copilotCLIWorktreeManagerService.getWorktreePath(id);
+	async function deleteSessionById(sessionId: string, options?: { keepWorktree?: boolean }): Promise<void> {
+		const worktree = await copilotCLIWorktreeManagerService.getWorktreeProperties(sessionId);
+		const worktreePath = await copilotCLIWorktreeManagerService.getWorktreePath(sessionId);
 
-		await copilotCLISessionService.deleteSession(id);
-		await copilotCliWorkspaceSession.deleteTrackedWorkspaceFolder(id);
+		await copilotCLISessionService.deleteSession(sessionId);
+		await copilotCliWorkspaceSession.deleteTrackedWorkspaceFolder(sessionId);
 
-		if (worktreePath) {
+		if (worktreePath && !options?.keepWorktree) {
 			const worktreeExists = await fileSystemService.stat(worktreePath).then(() => true, () => false);
 			if (worktreeExists) {
 				try {
@@ -1064,7 +1085,21 @@ export function registerCLIChatCommands(
 			}
 		}
 
-		await contentProvider.refreshSession({ reason: 'delete', sessionId: id });
+		await contentProvider.refreshSession({ reason: 'delete', sessionId });
+	}
+
+	/**
+	 * Determine whether the worktree at `worktreePath` is still in use by another
+	 * non-archived, non-sub-session sibling. Used to gate worktree deletion.
+	 */
+	async function shouldKeepWorktreeForOtherSessions(sessionId: string, worktreePath: vscode.Uri): Promise<boolean> {
+		const siblings = await getBlockingSiblingSessionsForFolder(
+			worktreePath,
+			sessionId,
+			metadataStore,
+			copilotCliWorkspaceSession,
+		);
+		return siblings.length > 0;
 	}
 
 	// Terminal integration setup: resolve session dirs for terminal links.
@@ -1076,8 +1111,9 @@ export function registerCLIChatCommands(
 		if (sessionItem?.resource) {
 			const id = SessionIdForCLI.parse(sessionItem.resource);
 			const worktreePath = await copilotCLIWorktreeManagerService.getWorktreePath(id);
+			const keepWorktree = !!worktreePath && await shouldKeepWorktreeForOtherSessions(id, worktreePath);
 
-			const confirmMessage = worktreePath
+			const confirmMessage = (worktreePath && !keepWorktree)
 				? l10n.t('Are you sure you want to delete the session and its associated worktree?')
 				: l10n.t('Are you sure you want to delete the session?');
 
@@ -1089,7 +1125,7 @@ export function registerCLIChatCommands(
 			);
 
 			if (result === deleteLabel) {
-				await deleteSessionById(id);
+				await deleteSessionById(id, { keepWorktree });
 			}
 		}
 	}));
@@ -1116,7 +1152,9 @@ export function registerCLIChatCommands(
 		for (const sessionItem of sessionItems) {
 			if (sessionItem.resource) {
 				const id = SessionIdForCLI.parse(sessionItem.resource);
-				await deleteSessionById(id);
+				const worktreePath = await copilotCLIWorktreeManagerService.getWorktreePath(id);
+				const keepWorktree = !!worktreePath && await shouldKeepWorktreeForOtherSessions(id, worktreePath);
+				await deleteSessionById(id, { keepWorktree });
 			}
 		}
 	}));