CPython extensions providing optimized execution of Python bytecode (e.g. the Cinder JIT) may need to hook into the lifecycle of code objects to determine what to optimize or to free resources allocated for code objects that no longer exist. We propose adding an API to allow extensions to set callbacks that will be invoked whenever code objects are created or destroyed.

Proposed API:

typedef enum {
  PYCODE_LCEVT_CREATED,
  PYCODE_LCEVT_DESTROYED
} PyCode_LifecycleEvent;

// A callback to be called when a code object is created or about to be destroyed.
typedef void(*PyCode_LifecycleCallback)(
  PyCode_LifecycleEvent event,
  PyCodeObject* code);

void PyCode_SetLifecycleCallback(PyCode_LifecycleCallback callback);
PyCode_LifecycleCallback PyCode_GetLifecycleCallback();

In which header file would you put that? Maybe this is simple enough that you should just submit a PR?

In which header file would you put that?

would Include/cpython/code.h make sense for this API?

Maybe this is simple enough that you should just submit a PR?

hopefully yes, we intend to do that for 3.12.
does the proposed API look reasonable?

The API looks reasonable -- I'd spell LifeCycle with two capital letters (though Wikipedia seems divided on this), and I'd start the enum values with PY_CODE, similar to _PyCodeLocationInfoKind in the same file. The implementation would seem straightforward, and code objects aren't created or destroyed at a monstrous rate (it might be worth seeing if this slows down unmarshalling noticeably, but I doubt it). The callback should probably be stored in the per-interpreter state.

Unfotunately, there are many buildbots failing to build this PR. Check buildbot.python.org/all/#/release_status for reference

As per our buildbot policy, this PR will be reverted if the buildbot fleet is not fixed in the next 24h. @markshannon @itamaro can you please take a look?

I have opened #99976. I will close it if the issue is fixed before the deadline.

this issue can be closed now!