Fix uninitialized seek position in VectorStream

src/common/serialization/vst3/base.cpp

@@ -193,7 +193,7 @@ VectorStream::VectorStream(Steinberg::IBStream* stream) {
     int64 size;
     assert(stream->tell(&size) == Steinberg::kResultOk);
 
-    int32 num_bytes_read;
+    int32 num_bytes_read = 0;
     buffer.resize(size);
     assert(stream->seek(0, Steinberg::IBStream::IStreamSeekMode::kIBSeekSet) ==
            Steinberg::kResultOk);
@@ -227,14 +227,12 @@ tresult VectorStream::write_back(Steinberg::IBStream* stream) const {
         return Steinberg::kInvalidArgument;
     }
 
-    int32 num_bytes_written;
+    int32 num_bytes_written = 0;
     assert(stream->seek(0, kIBSeekSet) == Steinberg::kResultOk);
-    // When writing zero bytes, some hosts will return `kResultFalse`
-    if (stream->write(const_cast<uint8_t*>(buffer.data()), buffer.size(),
-                      &num_bytes_written) == Steinberg::kResultOk) {
-        assert(num_bytes_written == 0 ||
-               static_cast<size_t>(num_bytes_written) == buffer.size());
-    }
+    assert(stream->write(const_cast<uint8_t*>(buffer.data()), buffer.size(),
+                         &num_bytes_written) == Steinberg::kResultOk);
+    assert(num_bytes_written == 0 ||
+           static_cast<size_t>(num_bytes_written) == buffer.size());
 
     return Steinberg::kResultOk;
 }
@@ -276,7 +274,7 @@ tresult PLUGIN_API VectorStream::write(void* buffer,
     }
 
     std::copy_n(reinterpret_cast<uint8_t*>(buffer), numBytes,
-                &this->buffer[seek_position]);
+                this->buffer.begin() + seek_position);
 
     seek_position += numBytes;
     if (numBytesWritten) {

src/common/serialization/vst3/base.h

@@ -225,7 +225,7 @@ class VectorStream : public Steinberg::IBStream,
 
    private:
     std::vector<uint8_t> buffer;
-    size_t seek_position;
+    size_t seek_position = 0;
 };
 
 #pragma GCC diagnostic pop

src/wine-host/bridges/vst3.cpp

@@ -139,7 +139,7 @@ void Vst3Bridge::run() {
             },
             [&](Vst3PluginProxy::GetState& request)
                 -> Vst3PluginProxy::GetState::Response {
-                VectorStream stream;
+                VectorStream stream{};
                 tresult result;
 
                 // This same function is defined in both `IComponent` and
@@ -288,6 +288,8 @@ void Vst3Bridge::run() {
                 // and pass that to the initialize function. This object should
                 // be cleaned up again during `Vst3PluginProxy::Destruct`.
                 // TODO: This needs changing when we get to `Vst3HostProxy`
+                // TODO: Does this have to be run from the UI thread? Figure out
+                //       if it does
                 Steinberg::FUnknown* context = nullptr;
                 if (request.host_application_context_args) {
                     object_instances[request.instance_id]