Fix SherpaOnnx finalizer crash with DllNotFoundException

src/OpenClaw.Tray.WinUI/Services/TextToSpeech/PiperTextToSpeechClient.cs

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using OpenClaw.Shared;
@@ -23,6 +24,10 @@ namespace OpenClawTray.Services;
 /// </summary>
 public sealed class PiperTextToSpeechClient : IDisposable
 {
+    private const string SherpaNativeLibrary = "sherpa-onnx-c-api";
+    private static readonly object s_nativeLibraryLock = new();
+    private static IntPtr s_nativeLibraryHandle;
+
     private readonly IOpenClawLogger _logger;
     private readonly string _voiceId;
     private readonly OfflineTts _tts;
@@ -53,6 +58,7 @@ public PiperTextToSpeechClient(IOpenClawLogger logger, PiperVoiceManager voices,
         config.Model.Debug = 0;
         config.MaxNumSentences = 2;
 
+        EnsureNativeLibraryLoaded();
         _tts = new OfflineTts(config);
         _logger.Info($"Piper voice '{_voiceId}' loaded (sample rate {_tts.SampleRate} Hz, {config.Model.NumThreads} threads)");
     }
@@ -126,10 +132,31 @@ private static byte[] ConvertFloatPcmToWav(float[] samples, int sampleRate)
         return ms.ToArray();
     }
 
+    private static void EnsureNativeLibraryLoaded()
+    {
+        lock (s_nativeLibraryLock)
+        {
+            if (s_nativeLibraryHandle != IntPtr.Zero)
+                return;
+
+            if (!NativeLibrary.TryLoad(
+                    SherpaNativeLibrary,
+                    typeof(OfflineTts).Assembly,
+                    DllImportSearchPath.SafeDirectories,
+                    out s_nativeLibraryHandle))
+            {
+                throw new DllNotFoundException("Piper TTS native library could not be loaded.");
+            }
+        }
+    }
+
     public void Dispose()
     {
         if (_disposed) return;
         _disposed = true;
+        // SherpaOnnx suppresses its finalizer only after native cleanup succeeds.
+        // Suppress first so a cleanup failure cannot retry from the finalizer thread.
+        GC.SuppressFinalize(_tts);
         // slopwatch-ignore: SW003 Cleanup is best-effort; failure cannot improve caller state and the original outcome is preserved.
         try { _tts.Dispose(); } catch { /* swallow */ }
         // slopwatch-ignore: SW003 Cleanup is best-effort; failure cannot improve caller state and the original outcome is preserved.

tests/OpenClaw.Tray.Tests/PiperTextToSpeechClientContractTests.cs

@@ -0,0 +1,48 @@
+namespace OpenClaw.Tray.Tests;
+
+public sealed class PiperTextToSpeechClientContractTests
+{
+    private static string ReadSource() =>
+        File.ReadAllText(Path.Combine(
+            TestRepositoryPaths.GetRepositoryRoot(),
+            "src",
+            "OpenClaw.Tray.WinUI",
+            "Services",
+            "TextToSpeech",
+            "PiperTextToSpeechClient.cs"));
+
+    [Fact]
+    public void NativeLibrary_IsLoadedBeforeFinalizableWrapperConstruction()
+    {
+        var source = ReadSource();
+
+        AssertInOrder(
+            source,
+            "EnsureNativeLibraryLoaded();",
+            "_tts = new OfflineTts(config);");
+        Assert.Contains("NativeLibrary.TryLoad(", source);
+        Assert.Contains("typeof(OfflineTts).Assembly", source);
+        Assert.Contains("DllImportSearchPath.SafeDirectories", source);
+        Assert.Contains("out s_nativeLibraryHandle", source);
+    }
+
+    [Fact]
+    public void Dispose_SuppressesFinalizerBeforeNativeCleanup()
+    {
+        var source = ReadSource();
+
+        AssertInOrder(
+            source,
+            "GC.SuppressFinalize(_tts);",
+            "_tts.Dispose();");
+    }
+
+    private static void AssertInOrder(string source, string first, string second)
+    {
+        var firstIndex = source.IndexOf(first, StringComparison.Ordinal);
+        var secondIndex = source.IndexOf(second, StringComparison.Ordinal);
+
+        Assert.True(firstIndex >= 0, $"Missing expected source fragment: {first}");
+        Assert.True(secondIndex > firstIndex, $"Expected '{first}' before '{second}'.");
+    }
+}