Fix voice sample validation on Python 3.13 (fixes #852) (#853)

* Fix voice sample validation on Python 3.13

Python 3.13 removed audioop from the standard library, which broke reference
audio validation when adding voice samples. Add the audioop-lts backport for
3.13+ installs and bundle audioop in PyInstaller builds on the same versions.

* style(tests): satisfy Ruff import ordering

---------

Co-authored-by: Jamie Pine <[email protected]>

backend/build_binary.py

@@ -330,6 +330,9 @@ def build_server(cuda=False, rocm=False):
         ]
     )
 
+    if sys.version_info >= (3, 13):
+        args.extend(["--hidden-import", "audioop"])
+
     # Add CUDA/ROCm-specific hidden imports
     if cuda or rocm:
         variant = "ROCm" if rocm else "CUDA"

backend/requirements.txt

@@ -53,6 +53,7 @@ en_core_web_sm @ https://github.com/explosion/spacy-models/releases/download/en_
 unidic-lite>=1.0.8
 
 # Audio processing
+audioop-lts>=0.2.1; python_version >= "3.13"
 librosa>=0.10.0
 soundfile>=0.12.0
 numpy>=1.24.0,<2.0

backend/tests/test_audioop_python313.py

@@ -0,0 +1,123 @@
+"""
+Regression tests for issue #852: audioop removed from Python 3.13 stdlib.
+
+Voice sample validation imports audioop transitively (librosa → audioread).
+The audioop-lts backport must be declared in requirements and bundled in
+PyInstaller builds on 3.13+.
+"""
+
+import re
+import sys
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+from build_binary import build_server
+
+
+@pytest.fixture
+def backend_dir():
+    return Path(__file__).parent.parent
+
+
+class TestAudioopRequirements:
+    def test_requirements_declare_audioop_lts_for_python_313(self, backend_dir):
+        content = (backend_dir / "requirements.txt").read_text()
+        assert re.search(
+            r"^audioop-lts.*python_version\s*>=\s*['\"]3\.13['\"]",
+            content,
+            re.MULTILINE,
+        ), "requirements.txt must pin audioop-lts for Python 3.13+"
+
+
+@pytest.mark.skipif(sys.version_info < (3, 13), reason="Python 3.13+ only")
+class TestAudioopRuntime:
+    def test_audioop_importable(self):
+        import audioop  # noqa: F401
+
+    def test_validate_reference_wav_does_not_fail_on_missing_audioop(self, tmp_path):
+        import numpy as np
+        import soundfile as sf
+        from utils.audio import validate_and_load_reference_audio
+
+        sr = 24000
+        t = np.arange(int(sr * 3), dtype=np.float32) / sr
+        audio = (0.3 * np.sin(2 * np.pi * 220 * t)).astype(np.float32)
+        path = tmp_path / "reference.wav"
+        sf.write(str(path), audio, sr)
+
+        ok, err, out_audio, out_sr = validate_and_load_reference_audio(str(path))
+
+        assert ok, err
+        assert out_audio is not None
+        assert out_sr == sr
+        assert "audioop" not in (err or "").lower()
+
+
+class TestAudioopBuildArgs:
+    @staticmethod
+    def _hidden_imports(args):
+        imports = []
+        for i, arg in enumerate(args):
+            if arg == "--hidden-import" and i + 1 < len(args):
+                imports.append(args[i + 1])
+        return imports
+
+    def test_pyinstaller_includes_audioop_on_python_313(self):
+        class FakeVersionInfo(tuple):
+            @property
+            def major(self):
+                return self[0]
+
+            @property
+            def minor(self):
+                return self[1]
+
+            @property
+            def micro(self):
+                return self[2]
+
+        fake_313 = FakeVersionInfo((3, 13, 0, "final", 0))
+
+        with (
+            patch("build_binary.PyInstaller.__main__.run") as mock_run,
+            patch("build_binary.platform.system", return_value="Linux"),
+            patch("build_binary.is_apple_silicon", return_value=False),
+            patch("build_binary.os.chdir"),
+            patch("build_binary.sys.version_info", fake_313),
+        ):
+            build_server()
+            args = mock_run.call_args[0][0]
+
+        assert "audioop" in self._hidden_imports(args)
+
+    def test_pyinstaller_omits_audioop_on_python_312(self):
+        class FakeVersionInfo(tuple):
+            @property
+            def major(self):
+                return self[0]
+
+            @property
+            def minor(self):
+                return self[1]
+
+            @property
+            def micro(self):
+                return self[2]
+
+        fake_312 = FakeVersionInfo((3, 12, 0, "final", 0))
+
+        with (
+            patch("build_binary.PyInstaller.__main__.run") as mock_run,
+            patch("build_binary.platform.system", return_value="Linux"),
+            patch("build_binary.is_apple_silicon", return_value=False),
+            patch("build_binary.os.chdir"),
+            patch("build_binary.sys.version_info", fake_312),
+        ):
+            build_server()
+            args = mock_run.call_args[0][0]
+
+        assert "audioop" not in self._hidden_imports(args)