Add GPU worker debug logging to diagnose ZeroGPU import errors

ZeroGPU only forwards exception class names, not messages. This adds:
- Import tests written to debug_gpu.log before conversion attempt
- Full traceback logged on error
- "Debug GPU" tab in UI to read the log file after an error

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -409,6 +409,25 @@ with gr.Blocks(
                 outputs=[models_delete_status, models_table],
             )
 
+        # Tab 4: Debug (temporary)
+        with gr.TabItem("Debug GPU"):
+            gr.Markdown("### Logs GPU Worker (pour diagnostic)")
+            debug_output = gr.Textbox(
+                label="Derniers logs GPU",
+                interactive=False,
+                lines=20,
+            )
+            debug_btn = gr.Button("Lire les logs", size="sm")
+
+            def read_debug_log():
+                log_path = "/home/user/app/debug_gpu.log"
+                if os.path.exists(log_path):
+                    with open(log_path, "r") as f:
+                        return f.read()
+                return "Aucun log disponible. Lancez d'abord une conversion."
+
+            debug_btn.click(fn=read_debug_log, outputs=[debug_output])
+
 
 if __name__ == "__main__":
     app.launch(server_name="0.0.0.0")

pipeline/inference.py

@@ -169,6 +169,21 @@ def crossfade(chunk1, chunk2, overlap):
     return chunk2
 
 
+DEBUG_LOG = "/home/user/app/debug_gpu.log"
+
+
+def _test_import(name, module_path, subattr=None):
+    """Test a single import and return (ok, error_msg)."""
+    try:
+        import importlib
+        mod = importlib.import_module(module_path)
+        if subattr:
+            getattr(mod, subattr)
+        return True, "OK"
+    except Exception as ie:
+        return False, "{}: {}".format(type(ie).__name__, ie)
+
+
 @spaces.GPU(duration=120)
 def convert_voice(
     audio_path,
@@ -190,9 +205,40 @@ def convert_voice(
     app_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
     if app_dir not in sys.path:
         sys.path.insert(0, app_dir)
-    # Also ensure current working directory is the app directory
     os.chdir(app_dir)
 
+    # Write debug diagnostics BEFORE attempting anything
+    try:
+        with open(DEBUG_LOG, "w") as f:
+            f.write("=== GPU Worker Debug ===\n")
+            f.write("app_dir: {}\n".format(app_dir))
+            f.write("cwd: {}\n".format(os.getcwd()))
+            f.write("sys.path[:5]: {}\n".format(sys.path[:5]))
+            f.write("modules/ exists: {}\n".format(os.path.isdir(os.path.join(app_dir, "modules"))))
+            f.write("hf_utils.py exists: {}\n".format(os.path.isfile(os.path.join(app_dir, "hf_utils.py"))))
+            f.write("cuda available: {}\n".format(torch.cuda.is_available()))
+
+            # Test each critical import
+            tests = [
+                ("yaml", "yaml", None),
+                ("munch", "munch", "Munch"),
+                ("einops", "einops", None),
+                ("transformers", "transformers", "WhisperModel"),
+                ("modules.commons", "modules.commons", "build_model"),
+                ("hf_utils", "hf_utils", "load_custom_model_from_hf"),
+                ("modules.campplus.DTDNN", "modules.campplus.DTDNN", "CAMPPlus"),
+                ("modules.bigvgan.bigvgan", "modules.bigvgan.bigvgan", "BigVGAN"),
+                ("modules.audio", "modules.audio", "mel_spectrogram"),
+                ("modules.rmvpe", "modules.rmvpe", "RMVPE"),
+            ]
+            for label, mod_path, attr in tests:
+                ok, msg = _test_import(label, mod_path, attr)
+                f.write("IMPORT {}: {} -> {}\n".format("OK" if ok else "FAIL", label, msg))
+
+            f.write("=== Import tests done ===\n")
+    except Exception:
+        pass
+
     try:
         return _convert_voice_impl(
             audio_path, reference_path, pitch, index_rate, diffusion_steps
@@ -200,10 +246,13 @@ def convert_voice(
     except Exception as e:
         import traceback
         tb = traceback.format_exc()
-        # Re-raise as RuntimeError with full details so ZeroGPU forwards the message
-        raise RuntimeError("Seed-VC error: {}: {}\n{}".format(
-            type(e).__name__, str(e), tb[-800:]
-        ))
+        try:
+            with open(DEBUG_LOG, "a") as f:
+                f.write("\n=== CONVERSION ERROR ===\n")
+                f.write(tb)
+        except Exception:
+            pass
+        raise
 
 
 def _convert_voice_impl(audio_path, reference_path, pitch, index_rate, diffusion_steps):