fix(media): update fallback process exit status after wait (#2473)

Signed-off-by: Rudy Celekli <47457359+rudycelekli@users.noreply.github.com>

CHANGELOG.md

@@ -86,6 +86,8 @@ metadata and the backend fallback mirror it.
 - The Twilio guide and integration directory describe the guided setup and in-app integration pages (#2304)
 
 ### Fixed
+
+- Media subprocess fallback reports the completed exit status after waiting (#2473) — thanks @rudycelekli!
 - Dub assembly, cached segments and audio tools can read generated WAV files when TorchCodec is missing or cannot load (#2379) — thanks @tokutei58301-boop!
 - Remote API-key and share-PIN clients can record and read export history while native filesystem operations stay local (#2383, #2384) — thanks @sedatdagg!
 - Concurrent job events receive unique sequence numbers (#2384) — thanks @sedatdagg!

backend/services/ffmpeg_utils.py

@@ -432,7 +432,9 @@ async def _spawn_thread_fallback(cmd, **kwargs):
             return out, err
 
         async def wait(self):
-            return await loop.run_in_executor(None, self._popen.wait)
+            code = await loop.run_in_executor(None, self._popen.wait)
+            self.returncode = code
+            return code
 
         def kill(self):
             self._popen.kill()

docs/media-subprocess-fallback.md

@@ -0,0 +1,15 @@
+# Update fallback process exit status after wait
+
+The Windows-compatible subprocess wrapper exposes the completed child exit code after `wait()`, matching its public asyncio process contract.
+
+## Contract
+
+Store the completed Popen wait result in the wrapper returncode before returning it.
+
+The unsupported transport condition is reproduced with a selector loop on macOS; native Windows execution and the full application smoke matrix await hosted CI. No ffmpeg binary or model was needed for the process protocol regression.
+
+## Regression coverage
+
+The public helper regression is in `tests/test_voice_fallback_exit.py`.
+Run it with `python -m pytest -q tests/test_voice_fallback_exit.py` from the repository root.
+It uses local text, files or child processes; no model generation is required.

tests/test_voice_fallback_exit.py

@@ -0,0 +1,31 @@
+"""Real children on the unsupported-subprocess loop retain asyncio exit status."""
+import asyncio
+import sys
+import pytest
+
+class UnsupportedSubprocessLoop(asyncio.SelectorEventLoop):
+    async def _make_subprocess_transport(self, *args, **kwargs):
+        raise NotImplementedError
+
+@pytest.mark.parametrize("code", [0, 23])
+def test_public_spawn_wait_updates_returncode_on_fallback(code):
+    from services.ffmpeg_utils import spawn_subprocess
+    async def run():
+        proc = await spawn_subprocess(sys.executable, "-c", f"raise SystemExit({code})")
+        assert proc.uses_sync_pipes
+        assert await asyncio.wait_for(proc.wait(), 5) == code
+        assert proc.returncode == code
+        assert await proc.wait() == code
+    with asyncio.Runner(loop_factory=UnsupportedSubprocessLoop) as runner:
+        runner.run(run())
+
+def test_fallback_communicate_keeps_exit_code_and_real_output():
+    from services.ffmpeg_utils import spawn_subprocess
+    async def run():
+        proc = await spawn_subprocess(sys.executable, "-c", "import sys; sys.stdout.buffer.write(b'media child\\n'); raise SystemExit(7)", stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE)
+        out, err = await asyncio.wait_for(proc.communicate(), 5)
+        assert out == b"media child\n"
+        assert err == b""
+        assert proc.returncode == 7
+    with asyncio.Runner(loop_factory=UnsupportedSubprocessLoop) as runner:
+        runner.run(run())