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Add PyUnstable_Object_Dump() function: promote private _PyObject_Dump() to a public function #87
Description
I propose promoting the private _PyObject_Dump() function to a public function, as PyUnstable_Object_Dump().
API: void PyUnstable_Object_Dump(PyObject *op)
- Dump an object op to
stderr. This should only be used for debugging. - The output is intended to try dumping objects even after memory corruption (see the PR for the whole documentation).
- Example of output:
object address : 0x7f80124702c0
object refcount : 2
object type : 0x9902e0
object type name: str
object repr : 'abcdef'
See:
Vote:
Activity
vstinner commentedon Nov 12, 2025
Ping @serhiy-storchaka
vstinner commentedon Nov 17, 2025
Ping @serhiy-storchaka
vstinner commentedon Nov 18, 2025
Ok, the C API Working Group approved this API. Thanks you all!
serhiy-storchaka commentedon Nov 18, 2025
Is there a need to add a parameter for the output stream or file descriptor?
vstinner commentedon Nov 18, 2025
I don't think so. I prefer to hardcode stderr, since stderr is used for debugging. It simplify the code.
In practice, the code writes to the C
stderrstream and to the Pythonsys.stderrobject.vstinner commentedon Nov 18, 2025
Sorry, I just checked the code, it's only the C
stderrstream.encukou commentedon Dec 16, 2025
Reopening to make this fully public -- see the Discourse thread.
Expose this as
PyObject_Dumprather thanPyUnstable_Object_Dump.I'll abstain.
erlend-aasland commentedon Dec 16, 2025
Why do you abstain? From your latest comment over at DPO, it appears you are approving.
encukou commentedon Dec 16, 2025
I'd prefer either
PyUnstable_Object_Dump(purity -- debug helpers should be unstable) orPy_Dump(practicality -- short to type ingdb). I don't think the compromise solves much.But I'll yield to the majority.
davidhewitt commentedon Dec 16, 2025
What about
PyUnstable_Dump?vstinner commentedon Jan 8, 2026
Ping @serhiy-storchaka @zooba.
zooba commentedon Jan 12, 2026
+1 to
PyObject_Dumpencukou commentedon Jan 15, 2026
Ping @serhiy-storchaka
serhiy-storchaka commentedon Jan 15, 2026
Sorry, I though I already voted for this.
BTW, I recently searched bugs in
set, and needed to output the dump of the set, including empty and dummy entries. I initially tried to usePyUnstable_Object_Dump(), but it was not so helpful when output several dumps one after other. More compact format with indentation would be more convenient. But this was a special one-time case. I ended with using simplefprintf(). If makePyObject_Dump()more configurable, it will be less convenient in cases where it is currently used.vstinner commentedon Jan 16, 2026
The C API Working approved renaming the function to PyObject_Dump(). I close the issue. See PR python/cpython#142848 to rename the function.