fix: android race condition for snapshot dump

Author: thymikee

src/platforms/android/index.ts

@@ -449,12 +449,52 @@ async function dumpUiHierarchy(device: DeviceInfo): Promise<string> {
 }
 
 async function dumpUiHierarchyOnce(device: DeviceInfo): Promise<string> {
-  await runCmd(
+  // Preferred: stream XML directly to stdout, avoiding file I/O race conditions.
+  const streamed = await runCmd(
+    'adb',
+    adbArgs(device, ['exec-out', 'uiautomator', 'dump', '/dev/tty']),
+    { allowFailure: true },
+  );
+  if (streamed.exitCode === 0) {
+    const fromStream = extractUiDumpXml(streamed.stdout, streamed.stderr);
+    if (fromStream) return fromStream;
+  }
+
+  // Fallback: dump to file and read back.
+  // If `cat` fails with "no such file", the outer withRetry (via isRetryableAdbError) handles it.
+  const dumpPath = '/sdcard/window_dump.xml';
+  const dumpResult = await runCmd(
     'adb',
-    adbArgs(device, ['shell', 'uiautomator', 'dump', '/sdcard/window_dump.xml']),
+    adbArgs(device, ['shell', 'uiautomator', 'dump', dumpPath]),
   );
-  const result = await runCmd('adb', adbArgs(device, ['shell', 'cat', '/sdcard/window_dump.xml']));
-  return result.stdout;
+  const actualPath = resolveDumpPath(dumpPath, dumpResult.stdout, dumpResult.stderr);
+
+  const result = await runCmd('adb', adbArgs(device, ['shell', 'cat', actualPath]));
+  const xml = extractUiDumpXml(result.stdout, result.stderr);
+  if (!xml) {
+    throw new AppError('COMMAND_FAILED', 'uiautomator dump did not return XML', {
+      stdout: result.stdout,
+      stderr: result.stderr,
+    });
+  }
+  return xml;
+}
+
+function resolveDumpPath(defaultPath: string, stdout: string, stderr: string): string {
+  const text = `${stdout}\n${stderr}`;
+  const match = /dumped to:\s*(\S+)/i.exec(text);
+  return match?.[1] ?? defaultPath;
+}
+
+function extractUiDumpXml(stdout: string, stderr: string): string | null {
+  const text = `${stdout}\n${stderr}`;
+  const start = text.indexOf('<?xml');
+  const hierarchyStart = start >= 0 ? start : text.indexOf('<hierarchy');
+  if (hierarchyStart < 0) return null;
+  const end = text.lastIndexOf('</hierarchy>');
+  if (end < 0 || end < hierarchyStart) return null;
+  const xml = text.slice(hierarchyStart, end + '</hierarchy>'.length).trim();
+  return xml.length > 0 ? xml : null;
 }
 
 function isRetryableAdbError(err: unknown): boolean {
@@ -467,6 +507,7 @@ function isRetryableAdbError(err: unknown): boolean {
   if (stderr.includes('connection reset')) return true;
   if (stderr.includes('broken pipe')) return true;
   if (stderr.includes('timed out')) return true;
+  if (stderr.includes('no such file or directory')) return true;
   return false;
 }