C API prevents GC'ing externref values
alexcrichton opened this issue · comments
I'm in the process of trying to update wasmtime-py to the latest C API to weed out any issues ahead of the 20.0.0 release. One test is currently failing which asserts that a value is collected and unreferenced in Python, but it's failing. The general shape is:
- Create a
wasmtime_externref_t - Put that in
wasmtime_val_t - Pass that to
wasmtime_func_call - Run
store.gc() - Assert that the value has geen gc'd
The problem appears to be here if I'm understanding this correctly. Notably in this location there's no RootScope so the to_val, which creates a Rooted<T>, attaches itself to the Store directly meaning that it's now un-collect-able.
cc @fitzgen
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cc @peterhuene
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Yeah that function takes any impl AsContextMut and it is on callers to provide a suitable context, since that function cannot (it returns a rooted value, so that function can't create the scope, callers must).
So the question is: which caller needs to be updated to add a root scope? I guess wasmtime_func_call?