fix(coding-agent): keep codemode working after the install is updated or removed

Resolve the QuickJS wasm path once and spawn the bundled codemode worker
from an in-memory data: URL. Show a restart hint when errors occur after
the install changed on disk.

closes #10439

packages/coding-agent/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Fixed subscription logins such as Sign in with ChatGPT failing with `refresh_token_invalidated` after a request was cancelled during an OAuth token refresh
+- Fixed codemode failing for the rest of a session after a pnpm global update removed the running install, and added a restart hint when errors occur after pi was updated or removed on disk ([#10439](https://github.com/earendil-works/pi/issues/10439))
 
 ## [1.0.2] - 2026-10-04
 

packages/coding-agent/src/config.ts

@@ -480,16 +480,20 @@ export function getBundledInteractiveAssetPath(name: string): string {
 	return join(getInteractiveAssetsDir(), name);
 }
 
-let embeddedQuickJSWasmPath: string | undefined;
+let quickJSWasmPath: string | undefined;
 
 /** Called by the Bun entry with the path of the QuickJS wasm file embedded in the compiled executable. */
 export function setEmbeddedQuickJSWasmPath(path: string): void {
-	embeddedQuickJSWasmPath = path;
+	quickJSWasmPath = path;
 }
 
-/** Get path to `quickjs-wasi/quickjs.wasm`, the VM that runs codemode scripts. */
+/**
+ * Get path to `quickjs-wasi/quickjs.wasm`, the VM that runs codemode scripts. Resolved once so the
+ * compiled module cached per path keeps working after an update removes this install (#10439).
+ */
 export function getQuickJSWasmPath(): string {
-	return embeddedQuickJSWasmPath ?? createRequire(import.meta.url).resolve("quickjs-wasi/quickjs.wasm");
+	quickJSWasmPath ??= createRequire(import.meta.url).resolve("quickjs-wasi/quickjs.wasm");
+	return quickJSWasmPath;
 }
 
 /** Resolve the codemode worker entry for a release runtime. */
@@ -505,13 +509,44 @@ export function resolveCodemodeWorkerSpecifier(
 	return undefined;
 }
 
+let codemodeWorkerDataUrl: URL | undefined;
+
 /**
  * Get the codemode worker entry, or undefined to use the worker that ships next to pi-codemode.
  * The Bun and Node release builds both pass the worker as an extra entrypoint.
  */
 export function getCodemodeWorkerSpecifier(): string | URL | undefined {
 	const runtime = isBunBinary ? "bun-binary" : isBundledNode ? "bundled-node" : "unbundled";
-	return resolveCodemodeWorkerSpecifier(runtime, import.meta.url);
+	const specifier = resolveCodemodeWorkerSpecifier(runtime, import.meta.url);
+	if (runtime !== "bundled-node" || !(specifier instanceof URL)) return specifier;
+	// Spawn workers from an in-memory copy. An update replaces or deletes the file while this
+	// process keeps running (#10439). The bundle build keeps the worker free of relative imports
+	// and import.meta, so it runs from a data: URL.
+	codemodeWorkerDataUrl ??= new URL(`data:text/javascript;base64,${readFileSync(specifier).toString("base64")}`);
+	return codemodeWorkerDataUrl;
+}
+
+export type InstallChange = { kind: "updated"; version: string } | { kind: "removed" };
+
+/**
+ * Detect that the package this process runs from changed on disk, for example after `pi update`
+ * in another terminal. Code loaded on demand can then be missing or from another version.
+ *
+ * Checks the package.json read at startup. Resolving it again would walk up past a deleted install
+ * and could find an unrelated package.json, such as one in the home directory.
+ */
+export function detectInstallChange(packageJsonPath = startupPackageJsonPath): InstallChange | undefined {
+	// The Bun binary embeds its code, so replacing the executable does not affect this process.
+	if (isBunBinary || !packageJsonPath) return undefined;
+	let installed: PackageJson;
+	try {
+		installed = JSON.parse(stripBom(readFileSync(packageJsonPath, "utf-8"))) as PackageJson;
+	} catch (error) {
+		return (error as NodeJS.ErrnoException).code === "ENOENT" ? { kind: "removed" } : undefined;
+	}
+	return installed.version && installed.version !== VERSION
+		? { kind: "updated", version: installed.version }
+		: undefined;
 }
 
 // =============================================================================
@@ -528,8 +563,12 @@ interface PackageJson {
 }
 
 let pkg: PackageJson = {};
+/** The package.json this process started from, if one existed. */
+let startupPackageJsonPath: string | undefined;
 try {
-	pkg = JSON.parse(stripBom(readFileSync(getPackageJsonPath(), "utf-8"))) as PackageJson;
+	const packageJsonPath = getPackageJsonPath();
+	pkg = JSON.parse(stripBom(readFileSync(packageJsonPath, "utf-8"))) as PackageJson;
+	startupPackageJsonPath = packageJsonPath;
 } catch (e: unknown) {
 	const err = e as NodeJS.ErrnoException;
 	if (err.code !== "ENOENT") throw e;

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -58,6 +58,7 @@ import {
 	APP_NAME,
 	APP_TITLE,
 	CONFIG_DIR_NAME,
+	detectInstallChange,
 	getAgentDir,
 	getAuthPath,
 	getDebugLogPath,
@@ -545,6 +546,7 @@ export class InteractiveMode {
 
 	/** The `/bug` hint is shown at most once per session so error output stays readable. */
 	private bugReportHintShown = false;
+	private installChangeWarningShown = false;
 
 	// Extension UI state
 	private extensionSelector: ExtensionSelectorComponent | undefined = undefined;
@@ -2168,9 +2170,32 @@ export class InteractiveMode {
 	private maybeSuggestBugReport(message: AssistantMessage): void {
 		if (message.stopReason !== "error" || isRetryableAssistantError(message)) return;
 		if (/\b(?:abort(?:ed)?|cancel(?:l?ed)?)\b/i.test(message.errorMessage ?? "")) return;
+		if (this.maybeShowInstallChangeWarning()) return;
 		this.suggestBugReport();
 	}
 
+	/**
+	 * After an error, check whether an update replaced or removed this install while the session ran.
+	 * Code loaded on demand then fails with missing modules until restart (#10439). Returns true when
+	 * the install changed.
+	 */
+	private maybeShowInstallChangeWarning(): boolean {
+		if (this.installChangeWarningShown) return true;
+		const change = detectInstallChange();
+		if (!change) return false;
+		this.installChangeWarningShown = true;
+		const cause =
+			change.kind === "updated"
+				? `${APP_NAME} was updated to ${change.version} while this session was running (${VERSION})`
+				: `The ${APP_NAME} installation this session runs from was removed or replaced`;
+		const resumeCommand = formatResumeCommand(this.sessionManager);
+		const restart = resumeCommand
+			? `Restart with \`${resumeCommand}\` to continue this session.`
+			: `Restart ${APP_NAME}.`;
+		this.showWarning(`${cause}. Features that load code on demand can fail until restart. ${restart}`);
+		return true;
+	}
+
 	private renderCurrentSessionState(): void {
 		this.loadedResourcesContainer.clear();
 		this.chatContainer.clear();
@@ -3590,6 +3615,7 @@ export class InteractiveMode {
 			}
 
 			case "tool_execution_end": {
+				if (event.isError) this.maybeShowInstallChangeWarning();
 				const component = this.pendingTools.get(event.toolCallId);
 				if (component) {
 					component.updateResult({ ...event.result, isError: event.isError });

packages/coding-agent/test/config.test.ts

@@ -3,6 +3,7 @@ import { tmpdir } from "os";
 import { delimiter, join } from "path";
 import { afterEach, describe, expect, test } from "vitest";
 import {
+	detectInstallChange,
 	detectInstallMethod,
 	findNodePackageDir,
 	getSelfUpdateCommand,
@@ -449,3 +450,15 @@ describe("detectInstallMethod", () => {
 		);
 	});
 });
+
+describe("detectInstallChange", () => {
+	// Regression test for #10439: a deleted pnpm install must not fall back to a package.json further up.
+	test("reports a removed install instead of reading a package.json further up", () => {
+		tempDir = mkdtempSync(join(tmpdir(), "pi-install-change-"));
+		const installDir = join(tempDir, "global", "hash");
+		mkdirSync(installDir, { recursive: true });
+		writeFileSync(join(tempDir, "package.json"), JSON.stringify({ version: "0.0.1" }));
+		rmSync(installDir, { recursive: true, force: true });
+		expect(detectInstallChange(join(installDir, "package.json"))).toEqual({ kind: "removed" });
+	});
+});

scripts/build-coding-agent-bundle.mjs

@@ -186,7 +186,6 @@ if (dirname(bedrockLoaderOutput) !== dirname(oauthLoaderOutput)) {
 const lazyEntryPoints = {
 	anthropic: join(aiDistDir, "auth", "oauth", "anthropic.js"),
 	"bedrock-converse-stream": join(aiDistDir, "api", "bedrock-converse-stream.js"),
-	"codemode-worker": join(codingAgentDistDir, "extensions", "codemode", "worker.js"),
 	"github-copilot": join(aiDistDir, "auth", "oauth", "github-copilot.js"),
 	"image-resize-worker": join(codingAgentDistDir, "utils", "image-resize-worker.js"),
 	"kimi-coding": join(aiDistDir, "auth", "oauth", "kimi-coding.js"),
@@ -215,6 +214,30 @@ const lazyResult = await build({
 	splitting: false,
 });
 
+// getCodemodeWorkerSpecifier() in config.ts spawns the codemode worker from an in-memory data: URL
+// so codemode survives an update that replaces or deletes the install (#10439). A data: URL module
+// has no file location, so the worker must not use the createRequire(import.meta.url) banner,
+// require(), or imports other than Node builtins.
+const codemodeWorkerResult = await build({
+	...commonBuildOptions(),
+	banner: undefined,
+	entryNames: "[name]",
+	entryPoints: { "codemode-worker": join(codingAgentDistDir, "extensions", "codemode", "worker.js") },
+	outdir: dirname(bedrockLoaderOutput),
+	splitting: false,
+});
+for (const [outputPath, output] of Object.entries(codemodeWorkerResult.metafile.outputs)) {
+	const invalid = output.imports.filter((imported) => imported.kind !== "import-statement" || !isBuiltin(imported.path));
+	if (invalid.length > 0) {
+		throw new Error(
+			`Codemode worker must only import Node builtins: ${invalid.map((imported) => imported.path).join(", ")}`,
+		);
+	}
+	if (readFileSync(resolve(repoRoot, outputPath), "utf8").includes("import.meta")) {
+		throw new Error("Codemode worker must not use import.meta");
+	}
+}
+
 const imageResizeWorkerOutput = resolve(dirname(bedrockLoaderOutput), "image-resize-worker.js");
 if (dirname(imageResizeOutput) !== dirname(imageResizeWorkerOutput)) {
 	throw new Error("Image resize implementation and worker were emitted into different directories");
@@ -224,7 +247,8 @@ if (dirname(configOutput) !== dirname(bedrockLoaderOutput)) {
 	throw new Error("config.ts and the codemode worker were emitted into different directories");
 }
 
-validateExternalImports([mainResult.metafile, lazyResult.metafile]);
+const metafiles = [mainResult.metafile, lazyResult.metafile, codemodeWorkerResult.metafile];
+validateExternalImports(metafiles);
 const cliLauncher = `#!/usr/bin/env node
 import { createRequire, enableCompileCache } from "node:module";
 
@@ -235,7 +259,6 @@ writeFileSync(join(bundleDir, "cli.js"), cliLauncher);
 chmodSync(join(bundleDir, "cli.js"), 0o755);
 chmodSync(join(bundleDir, "rpc-entry.js"), 0o755);
 
-const files =
-	new Set([...Object.keys(mainResult.metafile.outputs), ...Object.keys(lazyResult.metafile.outputs)]).size + 1;
-const mib = (outputBytes([mainResult.metafile, lazyResult.metafile]) + cliLauncher.length) / (1024 * 1024);
+const files = new Set(metafiles.flatMap((metafile) => Object.keys(metafile.outputs))).size + 1;
+const mib = (outputBytes(metafiles) + cliLauncher.length) / (1024 * 1024);
 console.log(`Built ${relative(repoRoot, bundleDir)} (${files} files, ${mib.toFixed(1)} MiB)`);