fix(coding-agent): handle missing session cwd

packages/coding-agent/src/core/agent-session-runtime.ts

@@ -5,6 +5,7 @@ import type { AgentSessionRuntimeDiagnostic, AgentSessionServices } from "./agen
 import type { SessionStartEvent } from "./extensions/index.js";
 import { emitSessionShutdownEvent } from "./extensions/runner.js";
 import type { CreateAgentSessionResult } from "./sdk.js";
+import { assertSessionCwdExists } from "./session-cwd.js";
 import { SessionManager } from "./session-manager.js";
 
 /**
@@ -124,14 +125,15 @@ export class AgentSessionRuntime {
 		this._modelFallbackMessage = result.modelFallbackMessage;
 	}
 
-	async switchSession(sessionPath: string): Promise<{ cancelled: boolean }> {
+	async switchSession(sessionPath: string, cwdOverride?: string): Promise<{ cancelled: boolean }> {
 		const beforeResult = await this.emitBeforeSwitch("resume", sessionPath);
 		if (beforeResult.cancelled) {
 			return beforeResult;
 		}
 
 		const previousSessionFile = this.session.sessionFile;
-		const sessionManager = SessionManager.open(sessionPath);
+		const sessionManager = SessionManager.open(sessionPath, undefined, cwdOverride);
+		assertSessionCwdExists(sessionManager, this.cwd);
 		await this.teardownCurrent();
 		this.apply(
 			await this.createRuntime({
@@ -246,7 +248,7 @@ export class AgentSessionRuntime {
 		return { cancelled: false, selectedText };
 	}
 
-	async importFromJsonl(inputPath: string): Promise<{ cancelled: boolean }> {
+	async importFromJsonl(inputPath: string, cwdOverride?: string): Promise<{ cancelled: boolean }> {
 		const resolvedPath = resolve(inputPath);
 		if (!existsSync(resolvedPath)) {
 			throw new Error(`File not found: ${resolvedPath}`);
@@ -268,7 +270,8 @@ export class AgentSessionRuntime {
 			copyFileSync(resolvedPath, destinationPath);
 		}
 
-		const sessionManager = SessionManager.open(destinationPath, sessionDir);
+		const sessionManager = SessionManager.open(destinationPath, sessionDir, cwdOverride);
+		assertSessionCwdExists(sessionManager, this.cwd);
 		await this.teardownCurrent();
 		this.apply(
 			await this.createRuntime({
@@ -302,6 +305,7 @@ export async function createAgentSessionRuntime(
 		sessionStartEvent?: SessionStartEvent;
 	},
 ): Promise<AgentSessionRuntime> {
+	assertSessionCwdExists(options.sessionManager, options.cwd);
 	const result = await createRuntime(options);
 	if (process.cwd() !== result.services.cwd) {
 		process.chdir(result.services.cwd);

packages/coding-agent/src/core/session-cwd.ts

@@ -0,0 +1,59 @@
+import { existsSync } from "node:fs";
+
+export interface SessionCwdIssue {
+	sessionFile?: string;
+	sessionCwd: string;
+	fallbackCwd: string;
+}
+
+interface SessionCwdSource {
+	getCwd(): string;
+	getSessionFile(): string | undefined;
+}
+
+export function getMissingSessionCwdIssue(
+	sessionManager: SessionCwdSource,
+	fallbackCwd: string,
+): SessionCwdIssue | undefined {
+	const sessionFile = sessionManager.getSessionFile();
+	if (!sessionFile) {
+		return undefined;
+	}
+
+	const sessionCwd = sessionManager.getCwd();
+	if (!sessionCwd || existsSync(sessionCwd)) {
+		return undefined;
+	}
+
+	return {
+		sessionFile,
+		sessionCwd,
+		fallbackCwd,
+	};
+}
+
+export function formatMissingSessionCwdError(issue: SessionCwdIssue): string {
+	const sessionFile = issue.sessionFile ? `\nSession file: ${issue.sessionFile}` : "";
+	return `Stored session working directory does not exist: ${issue.sessionCwd}${sessionFile}\nCurrent working directory: ${issue.fallbackCwd}`;
+}
+
+export function formatMissingSessionCwdPrompt(issue: SessionCwdIssue): string {
+	return `cwd from session file does not exist\n${issue.sessionCwd}\n\ncontinue in current cwd\n${issue.fallbackCwd}`;
+}
+
+export class MissingSessionCwdError extends Error {
+	readonly issue: SessionCwdIssue;
+
+	constructor(issue: SessionCwdIssue) {
+		super(formatMissingSessionCwdError(issue));
+		this.name = "MissingSessionCwdError";
+		this.issue = issue;
+	}
+}
+
+export function assertSessionCwdExists(sessionManager: SessionCwdSource, fallbackCwd: string): void {
+	const issue = getMissingSessionCwdIssue(sessionManager, fallbackCwd);
+	if (issue) {
+		throw new MissingSessionCwdError(issue);
+	}
+}

packages/coding-agent/src/core/session-manager.ts

@@ -1270,12 +1270,13 @@ export class SessionManager {
 	 * Open a specific session file.
 	 * @param path Path to session file
 	 * @param sessionDir Optional session directory for /new or /branch. If omitted, derives from file's parent.
+	 * @param cwdOverride Optional cwd override instead of the session header cwd.
 	 */
-	static open(path: string, sessionDir?: string): SessionManager {
+	static open(path: string, sessionDir?: string, cwdOverride?: string): SessionManager {
 		// Extract cwd from session header if possible, otherwise use process.cwd()
 		const entries = loadEntriesFromFile(path);
 		const header = entries.find((e) => e.type === "session") as SessionHeader | undefined;
-		const cwd = header?.cwd ?? process.cwd();
+		const cwd = cwdOverride ?? header?.cwd ?? process.cwd();
 		// If no sessionDir provided, derive from file's parent directory
 		const dir = sessionDir ?? resolve(path, "..");
 		return new SessionManager(cwd, dir, path, true);