G3.2+G3.3: classify hang/crash vs audio stall + SEH per-channel plugin crash isolation (mute channel)

native_bridge/tests/seh_channel_test.cpp

@@ -0,0 +1,80 @@
+// native_bridge/tests/seh_channel_test.cpp
+// G3.3: SEH per-channel crash isolation. A plugin whose processAudioBlock
+// faults (access violation) must be caught by SafeProcessChannel -> renderAll
+// mutes the channel instead of taking down the whole bridge process.
+// Assert-based, no framework. Includes the engine .cpp (like shm_selfcheck).
+#include "../include/NativeInstrumentEngine.h"
+#include "../src/NativeInstrumentEngine.cpp"
+
+#include <cassert>
+#include <cstdio>
+#include <cstring>
+
+class CrashingStub : public INativeInstrument {
+public:
+    bool init(double, uint32_t) override { return true; }
+    void selectProgram(uint32_t, uint32_t, uint32_t) override {}
+    void noteOn(uint32_t, uint32_t, float, uint32_t) override {}
+    void noteOff(uint32_t, uint32_t, uint32_t) override {}
+    void controlChange(uint32_t, uint32_t, uint32_t) override {}
+    void programChange(uint32_t, uint32_t) override {}
+    void pitchBend(uint32_t, uint32_t) override {}
+    bool openGUI(void*) override { return false; }
+    void closeGUI() override {}
+    void processAudioBlock(float*, float*, uint32_t) override {
+        volatile int* p = nullptr;
+        *p = 42; // deliberate access violation
+    }
+};
+
+class OkStub : public INativeInstrument {
+public:
+    bool init(double, uint32_t) override { return true; }
+    void selectProgram(uint32_t, uint32_t, uint32_t) override {}
+    void noteOn(uint32_t, uint32_t, float, uint32_t) override {}
+    void noteOff(uint32_t, uint32_t, uint32_t) override {}
+    void controlChange(uint32_t, uint32_t, uint32_t) override {}
+    void programChange(uint32_t, uint32_t) override {}
+    void pitchBend(uint32_t, uint32_t) override {}
+    bool openGUI(void*) override { return false; }
+    void closeGUI() override {}
+    void processAudioBlock(float* outL, float* outR, uint32_t n) override {
+        for (uint32_t i = 0; i < n; ++i) { outL[i] = 1.0f; outR[i] = 2.0f; }
+    }
+};
+
+int main() {
+    // 1. Faulting plugin: SEH catches the AV, process survives, returns false.
+    {
+        float L[64] = {}, R[64] = {};
+        CrashingStub stub;
+        bool ok = SafeProcessChannel(&stub, L, R, 64);
+        assert(!ok);
+        // Block left untouched (renderAll continues without this channel).
+        bool allZero = true;
+        for (float f : L) if (f != 0.0f) allZero = false;
+        assert(allZero);
+    }
+    // 2. Healthy plugin passes through unchanged.
+    {
+        float L[64] = {}, R[64] = {};
+        OkStub stub;
+        bool ok = SafeProcessChannel(&stub, L, R, 64);
+        assert(ok);
+        assert(L[0] == 1.0f && R[0] == 2.0f);
+    }
+    // 3. Manager crash-mute flags: set, read, and renderAll skips a crashed
+    //    channel (no exception escapes into the audio loop).
+    {
+        InstrumentEngineManager mgr;
+        assert(!mgr.isCrashed(3));
+        mgr.markCrashed(3);
+        assert(mgr.isCrashed(3));
+        assert(!mgr.isCrashed(4)); // other channels unaffected
+        float L[64] = {}, R[64] = {};
+        mgr.renderAll(L, R, 64); // crashed + unassigned: no-op, no crash
+        assert(L[0] == 0.0f);
+    }
+    std::printf("SEH_CHANNEL_TEST PASS\n");
+    return 0;
+}