nan: Weird and inexplicable crashes when using TypedArrayContents

I’m getting really weird crashes with v8 array buffers / typed arrays

Base:

size_t numEntries = 2 * TOTAL_NUM_BANDS;
size_t numBytes = sizeof(float) * numEntries;
v8::Local<v8::ArrayBuffer> dataBuffer = v8::ArrayBuffer::New(v8::Isolate::GetCurrent(), numBytes);
v8::Local<v8::Float32Array> dataArr = v8::Float32Array::New(minMaxDataBuffer, 0, numEntries);

works:

 auto dataPtr = static_cast<float*>(dataBuffer->GetContents().Data());

segfaults:

auto test = Nan::TypedArrayContents<float>(dataArr);

…but it doesn’t segfault immediately, but rather a couple of seconds later, probably when some GC happens.

I don’t even need to do anything with the pointer. It is enough to construct a (temporary) Nan::TypedArrayContents

I have digged through the nan_typedarray_contents.h header

once I comment out

data = static_cast<char*>(buffer->GetBackingStore()->Data()) + byte_offset;

there is no crash.

I tried to find out what this is, but now it’s getting really weird:

auto dataPtr2 = static_cast<float*>(dataBuffer->GetBackingStore()->Data());
//auto dataPtr3 = static_cast<float*>(dataBuffer->GetBackingStore()->Data());

works. Where as

auto dataPtr2 = static_cast<float*>(dataBuffer->GetBackingStore()->Data());
auto dataPtr3 = static_cast<float*>(dataBuffer->GetBackingStore()->Data());

(just the first call repeated) segfaults immediately… I suppose this is a node bug?

I’m compiling against electron 8.0.0, node version should be 12.13.0

I’ll try with a later node / electron version now