FA1: unity-Preserve bypass kills preview onset latency; drain-slot reload keeps voices ringing through curve edits; velocity path proven end-to-end

tests/test_sample_map.cpp

@@ -1419,6 +1419,50 @@ static void testVelocityCurveResolvesToZone() {
     CHECK(r.zones[0].velocityCurve.equals(vst::VelocityCurve::linear()));
 }
 
+// FA1 bug 3a — the COMPOSED end-to-end regression, mirroring the processor's reload composition
+// exactly: an authored curve survives the component-state round-trip (the save/load seam), then
+// resolvePerformance -> buildZonedKeymap -> VoiceEngine (constructed with a Preserve window, the
+// DAW configuration) -> render, and the rendered level tracks velocity through the curve. This
+// is the full pure slice of the click-to-sound path; only the bridge read + WAV decode (shell
+// I/O) are outside it. A y=x curve at velocity 1 must be near-silent — NOT max volume.
+static void testVelocityCurveEndToEndThroughReloadComposition() {
+    // 1. The instrument's own state: one full-keyboard zone with a LINEAR curve (the exact edit
+    //    Daniel made), round-tripped through the v7 component-state wire (save -> load).
+    ComponentState s;
+    s.selectionId = "a";
+    PerformanceZone z = zone("a", 0, 127);
+    z.velocityCurve = vst::VelocityCurve::linear();
+    s.map.zones.push_back(z);
+    const ComponentState back = deserializeComponentState(serializeComponentState(s), 48000.0);
+    CHECK(back.map.zones.size() == 1);
+    if (back.map.zones.size() != 1) return;
+
+    // 2. Resolve against a live bank blob (the shared bank_book parse, root 60 intrinsic).
+    const std::string json = bookJson({makeSample("a", "Kick", "reasampler_bank/a.wav", 60)}, {});
+    const ResolvedPerformance rp = resolvePerformance(json, back.map);
+    CHECK(rp.zones.size() == 1);
+    if (rp.zones.size() != 1) return;
+    // The round-tripped zone still runs the PRESERVE product default (the DAW engine config).
+    CHECK(rp.zones[0].play.pitchEngine == PitchEngine::Preserve);
+
+    // 3. Build the zoned keymap from decoded DC-1 PCM and play it through an engine constructed
+    //    the way reloadFromBank constructs it (Preserve voices pre-sized to a real window).
+    auto steadyLevelAt = [&](int vel) -> double {
+        DecodedZonePcm pcm;
+        pcm.monoFrames.assign(4000, 1.0f);
+        pcm.sampleRate = 48000;
+        const Keymap km = buildZonedKeymap(rp.zones, {pcm});
+        VoiceEngine eng(16, km, /*preserveCap=*/8, /*window=*/256);
+        eng.noteOn(62, vel);  // transposed: the genuine OLA shifter path
+        std::vector<AudioSample> out;
+        eng.render(out, 1000);
+        return static_cast<double>(out[900]);  // steady state (ring fully DC past the window)
+    };
+    CHECK(approx(steadyLevelAt(127), 1.0));
+    CHECK(approx(steadyLevelAt(64), 64.0 / 127.0));
+    CHECK(steadyLevelAt(1) < 0.02);  // velocity 1 through y=x: near-silent, never max volume
+}
+
 static void testVelocityCurveV6BackCompatLiftsToFlat() {
     // A v6 PAYLOAD blob (marker + version 6 + full play tail + keyTrack, but NO velocity-curve field)
     // lifts every zone to VelocityCurve::flat() (R10-F1 Option A — flat y=1). This is the DELIBERATE
@@ -1822,6 +1866,7 @@ int main() {
     testVelocityCurveRoundTrip();
     testVelocityCurveThroughComponentEnvelope();
     testVelocityCurveResolvesToZone();
+    testVelocityCurveEndToEndThroughReloadComposition();
     testVelocityCurveV6BackCompatLiftsToFlat();
     testPlayParamsV2BackCompatLiftsToDefaults();
     testPlayParamsThroughComponentEnvelope();