JIT: _Py_uop_sym_set_recorded_type may receive a non-type at trace optimization time.
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interpreter-core
topic-JIT
type-bug
- Dominant language
- Python
- Stars
- 77.2k
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Description
Bug report
Bug description:
_Py_uop_sym_set_recorded_type asserts PyType_Check, but it's possible to have an instance change its __class__/type to a non-PyType_Check-ed class after JIT trace but right before JIT optimization time.
I think the fix is to convert that to a check instead of an assert?
CPython versions tested on:
CPython main branch
Operating systems tested on:
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by locating _Py_uop_sym_set_recorded_type and the JIT trace optimization path that calls it. Reproduce the class change described in the report, then verify that optimization handles a non-PyType_Check-ed class without the assertion failure and add or update a regression test if the relevant test location is found.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 52/100