fix(browser): handle extension relay page selection

src/browser/pw-session.get-page-for-targetid.extension-fallback.test.ts

@@ -0,0 +1,54 @@
+import { describe, expect, it, vi } from "vitest";
+
+describe("pw-session getPageForTargetId", () => {
+  it("falls back to the only page when CDP session attachment is blocked (extension relays)", async () => {
+    vi.resetModules();
+
+    const pageOn = vi.fn();
+    const contextOn = vi.fn();
+    const browserOn = vi.fn();
+    const browserClose = vi.fn(async () => {});
+
+    const context = {
+      pages: () => [],
+      on: contextOn,
+      newCDPSession: vi.fn(async () => {
+        throw new Error("Not allowed");
+      }),
+    } as unknown as import("playwright-core").BrowserContext;
+
+    const page = {
+      on: pageOn,
+      context: () => context,
+    } as unknown as import("playwright-core").Page;
+
+    // Fill pages() after page exists.
+    (context as unknown as { pages: () => unknown[] }).pages = () => [page];
+
+    const browser = {
+      contexts: () => [context],
+      on: browserOn,
+      close: browserClose,
+    } as unknown as import("playwright-core").Browser;
+
+    vi.doMock("playwright-core", () => ({
+      chromium: {
+        connectOverCDP: vi.fn(async () => browser),
+      },
+    }));
+
+    vi.doMock("./chrome.js", () => ({
+      getChromeWebSocketUrl: vi.fn(async () => null),
+    }));
+
+    const mod = await import("./pw-session.js");
+    const resolved = await mod.getPageForTargetId({
+      cdpUrl: "http://127.0.0.1:18792",
+      targetId: "NOT_A_TAB",
+    });
+    expect(resolved).toBe(page);
+
+    await mod.closePlaywrightBrowserConnection();
+    expect(browserClose).toHaveBeenCalled();
+  });
+});

src/browser/pw-session.ts

@@ -332,7 +332,13 @@ export async function getPageForTargetId(opts: {
   const first = pages[0];
   if (!opts.targetId) return first;
   const found = await findPageByTargetId(browser, opts.targetId);
-  if (!found) throw new Error("tab not found");
+  if (!found) {
+    // Extension relays can block CDP attachment APIs (e.g. Target.attachToBrowserTarget),
+    // which prevents us from resolving a page's targetId via newCDPSession(). If Playwright
+    // only exposes a single Page, use it as a best-effort fallback.
+    if (pages.length === 1) return first;
+    throw new Error("tab not found");
+  }
   return found;
 }