Is there any way to keep the vtable inside PyInner and still have the drop_rc/drop_weak? It's a lot more efficient to have PyObjectRef be pointer-sized, since that halves the memory usage for a ton of data structures that we use. I think you should be able to do let drop_rc = self.inner.vtable.drop_rc at the top of fn drop, and then call it later

It doesn't work for Weak pointers, unless we use something like what CPython does with a linked list.

Oh, true... hmm

Would it be possible to only make PyObjectWeak a fat pointer? Store it in PyObject, and then copy the vtable reference when we want to make a weak?

The other problem is that I get stack overflows again :(, gonna see what is causing those. Making PyObjectWeak a fat pointer might fix that.

I might also look into unifying the vtable and PyTypeRef, since CPython has the tp_dealloc slot and all, I just have to figure out how to make that safe still to create types

Hmmm more stack overflows. I put it in LLDB and it keeps calling the same destructor over and over... Weird.

Do you remember what the WASM bug was last time?

It looks like you figured it out, but I had made layout assumptions that didn't hold up on wasm, specifically wrt struct Inner { vtable, obj: PyObject<T> } vs just adding the vtable field to PyObject IIRC. The first one added extra padding on wasm that made the 2 options not equivalent, but I was assuming that they were.

This appears to fix #2381 FYI, if you want to add closes #2381 to your commit message.

edit: I guess it would be more accurate to say that "instead of immediately exiting and complaining at me, miri instead slowly heats up my CPU for >15 minutes while it chews through my entire 32gb of RAM". Miri is slow AF. I guess it's still a good sign.

@coolreader18 @carbotaniuman how is this ended up?

Now that the structure of pyobjectrc.rs has completely changed, does it make sense to keep this PR open as it currently stands?

FYI I'm finally working on a big overhaul to PyObjectRef's implementation/our object model that'll fix the UB: coolreader18:big-object-model-overhaul