fix(macos): keep JXA tracking when an app has no scriptable window

.github/workflows/build.yml

@@ -52,6 +52,9 @@ jobs:
       shell: bash
       run: |
         otool -l aw_watcher_window/aw-watcher-window-macos | grep -A4 'LC_BUILD_VERSION' | grep 'minos 12.0'
+    - uses: actions/setup-node@v4
+      with:
+        node-version: '22'
     - name: Run tests
       shell: bash
       run: |

aw_watcher_window/printAppStatus.jxa

@@ -17,43 +17,90 @@ var appName       = oProcess.displayedName();
 // and the previously set values will be cached otherwise
 var url = undefined, incognito = undefined, title = undefined;
 
+// Reported when the frontmost app has no window we can inspect. Some apps are
+// not scriptable via JXA at all, and some scriptable apps are open with no
+// window (or only a devtools window). An uncaught throw here aborts the whole
+// poll, so every window lookup below is guarded and falls back to this value.
+var NO_WINDOW_TITLE = "No window";
+
+// Best-effort title of the frontmost app's main window, read through the
+// Accessibility API (which also works for apps that don't support JXA
+// scripting). Returns undefined when no window title can be read.
+function axWindowTitle(proc) {
+  try {
+    var mainWindow = proc.windows().find(function(w) {
+      try {
+        return w.attributes.byName("AXMain").value() === true;
+      } catch (e) {
+        return false;
+      }
+    });
+    if (mainWindow) {
+      return mainWindow.attributes.byName("AXTitle").value();
+    }
+  } catch (e) {
+    // The app exposes no scriptable windows.
+  }
+  try {
+    // No window is flagged as AXMain (e.g. a dialog); take the first one.
+    return proc.windows()[0].attributes.byName("AXTitle").value();
+  } catch (e) {
+    return undefined;
+  }
+}
+
 // it's not possible to get the URL from firefox
 // https://stackoverflow.com/questions/17846948/does-firefox-offer-applescript-support-to-get-url-of-windows
 
 switch(appName) {
   case "Safari":
     // incognito is not available via safari applescript
-    url = Application(appName).documents[0].url();
-    title = Application(appName).documents[0].name();
+    try {
+      url = Application(appName).documents[0].url();
+      title = Application(appName).documents[0].name();
+    } catch (e) {
+      // Discard partial browser reads before using an Accessibility title.
+      url = undefined;
+      incognito = undefined;
+      // Safari can be open with no document (no window, or devtools only).
+      title = axWindowTitle(oProcess);
+    }
     break;
   case "Google Chrome":
   case "Google Chrome Canary":
   case "Chromium":
   case "Brave Browser":
-    const activeWindow = Application(appName).windows[0];
-    const activeTab = activeWindow.activeTab();
+    try {
+      var activeWindow = Application(appName).windows[0];
+      var activeTab = activeWindow.activeTab();
 
-    url = activeTab.url();
-    title = activeTab.name();
-    incognito = activeWindow.mode() === 'incognito';
+      url = activeTab.url();
+      title = activeTab.name();
+      incognito = activeWindow.mode() === 'incognito';
+    } catch (e) {
+      // Discard partial browser reads before using an Accessibility title.
+      url = undefined;
+      incognito = undefined;
+      // The browser can be open with no window.
+      title = axWindowTitle(oProcess);
+    }
     break;
   case "Firefox":
   case "Firefox Developer Edition":
-    title = Application(appName).windows[0].name();
+    try {
+      title = Application(appName).windows[0].name();
+    } catch (e) {
+      title = axWindowTitle(oProcess);
+    }
     break;
   default:
-    mainWindow = oProcess.
-      windows().
-      find(w => w.attributes.byName("AXMain").value() === true)
+    title = axWindowTitle(oProcess);
+}
 
-    // in some cases, the primary window of an application may not be found
-    // this occurs rarely and seems to be triggered by switching to a different application
-    if(mainWindow) {
-      title = mainWindow.
-        attributes.
-        byName("AXTitle").
-        value()
-    }
+// The Python side requires a title key (it indexes current_window["title"]),
+// so never leave it undefined.
+if (title === undefined) {
+  title = NO_WINDOW_TITLE;
 }
 
 // key names must match expected names in lib.py

tests/jxa_harness.js

@@ -0,0 +1,94 @@
+// Control-flow regression tests for the real JXA source, not a replacement
+// implementation. These stubs do not validate macOS Accessibility/JXA APIs.
+const assert = require("assert");
+const fs = require("fs");
+const vm = require("vm");
+const source = fs.readFileSync(process.argv[2], "utf8").replace(/^#![^\n]*\n/, "");
+
+function fail() {
+  throw new Error("window disappeared or attribute unavailable");
+}
+
+function windowWithTitle(title, isMain = false) {
+  return {
+    attributes: {
+      byName: (name) => ({
+        value: () => name === "AXMain" ? isMain : title,
+      }),
+    },
+  };
+}
+
+function capture(appName, app = {}, windows = () => []) {
+  const proc = { displayedName: () => appName, windows };
+  const result = vm.runInNewContext(source, {
+    Application: (name) => name === "System Events"
+      ? { processes: { whose: () => [proc] } }
+      : app,
+  }, { timeout: 1000 });
+  return JSON.parse(result);
+}
+
+let cases = 0;
+function check(name, actual, expected) {
+  assert.deepStrictEqual(actual, expected, name);
+  cases++;
+}
+
+check("Safari document", capture("Safari", {
+  documents: [{ url: () => "https://example.com", name: () => "Example" }],
+}), { app: "Safari", title: "Example", url: "https://example.com" });
+
+check("Safari no document", capture("Safari", { documents: [] },
+  () => [windowWithTitle("DevTools", true)]),
+{ app: "Safari", title: "DevTools" });
+
+check("Safari no windows", capture("Safari", { documents: [] }),
+  { app: "Safari", title: "No window" });
+
+check("Safari title read fails after URL", capture("Safari", {
+  documents: [{ url: () => "https://stale.example", name: fail }],
+}, () => [windowWithTitle("Fallback", true)]),
+{ app: "Safari", title: "Fallback" });
+
+for (const appName of ["Google Chrome", "Google Chrome Canary", "Chromium", "Brave Browser"]) {
+  for (const mode of ["normal", "incognito"]) {
+    check(`${appName} ${mode}`, capture(appName, { windows: [{
+      activeTab: () => ({ url: () => "https://example.com", name: () => "Example" }),
+      mode: () => mode,
+    }] }), { app: appName, title: "Example", url: "https://example.com", incognito: mode === "incognito" });
+  }
+  check(`${appName} no windows`, capture(appName, { windows: [] }),
+    { app: appName, title: "No window" });
+  check(`${appName} title read fails after URL`, capture(appName, { windows: [{
+    activeTab: () => ({ url: () => "https://stale.example", name: fail }),
+    mode: () => "incognito",
+  }] }, () => [windowWithTitle("Fallback", true)]),
+  { app: appName, title: "Fallback" });
+  check(`${appName} mode read fails after URL and title`, capture(appName, { windows: [{
+    activeTab: () => ({ url: () => "https://stale.example", name: () => "Stale" }),
+    mode: fail,
+  }] }, () => [windowWithTitle("Fallback", true)]),
+  { app: appName, title: "Fallback" });
+}
+
+for (const appName of ["Firefox", "Firefox Developer Edition"]) {
+  check(`${appName} normal`, capture(appName, { windows: [{ name: () => "Example" }] }),
+    { app: appName, title: "Example" });
+  check(`${appName} no windows`, capture(appName, { windows: [] }),
+    { app: appName, title: "No window" });
+}
+
+check("unscriptable app", capture("ElectronApp", {}, fail),
+  { app: "ElectronApp", title: "No window" });
+check("throwing attributes", capture("ElectronApp", {}, () => [{ attributes: { byName: fail } }]),
+  { app: "ElectronApp", title: "No window" });
+check("main window preferred", capture("Terminal", {}, () => [
+  windowWithTitle("zsh"), windowWithTitle("vim", true),
+]), { app: "Terminal", title: "vim" });
+check("first window fallback", capture("Finder", {}, () => [windowWithTitle("Desktop")]),
+  { app: "Finder", title: "Desktop" });
+check("empty title preserved", capture("Terminal", {}, () => [windowWithTitle("", true)]),
+  { app: "Terminal", title: "" });
+
+console.log(`${cases} JXA control-flow cases passed`);

tests/test_jxa.py

@@ -0,0 +1,25 @@
+"""Exercise JXA control flow with stubs; native macOS API checks remain manual."""
+
+from pathlib import Path
+import shutil
+import subprocess
+
+import pytest
+
+
+def test_jxa_fallbacks():
+    node = shutil.which("node")
+    if node is None:
+        pytest.skip("Node.js is required for the JXA control-flow harness")
+    root = Path(__file__).resolve().parents[1]
+    result = subprocess.run(
+        [
+            node,
+            str(root / "tests" / "jxa_harness.js"),
+            str(root / "aw_watcher_window" / "printAppStatus.jxa"),
+        ],
+        capture_output=True,
+        text=True,
+        timeout=30,
+    )
+    assert result.returncode == 0, result.stdout + result.stderr