bpo-36389: _PyObject_CheckConsistency() now also works in release mode by vstinner · Pull Request #16612 · python/cpython (original) (raw)
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bpo-36389, bpo-38376: Modify the following functions to also work in
release mode:
- _PyDict_CheckConsistency()
- _PyObject_CheckConsistency()
- _PyType_CheckConsistency()
- _PyUnicode_CheckConsistency()
The main function _PyObject_CheckConsistency() can be used for
debugging purpose, like crash in visit_decref() of the GC.
_PyBytesWriter_CheckConsistency() now returns 1 and is only used with
assert().
https://bugs.python.org/issue36389
Roping in the 3.8 release manager for the question of whether this should go into 3.8.0.
This change mostly impacts the debugging experience. It doesn't change Python in release mode: modified functions only becomes available in release mode, but are never called.
@Yhg1s: Thanks for your review. I agree that "define ASSERT" is confusing. I renamed my macros to "CHECK" as you suggested.
I also included other fixes for these debug functions.
bpo-36389, bpo-38376: The _PyObject_CheckConsistency() function is now also available in release mode. For example, it can be used to debug a crash in the visit_decref() function of the GC.
Modify the following functions to also work in release mode:
- _PyDict_CheckConsistency()
- _PyObject_CheckConsistency()
- _PyType_CheckConsistency()
- _PyUnicode_CheckConsistency()
Other changes:
- _PyMem_IsPtrFreed(ptr) now also returns 1 if ptr is NULL (equals to 0).
- _PyBytesWriter_CheckConsistency() now returns 1 and is only used with assert().
- Reorder _PyObject_Dump() to write safe fields first, and only attempt to render repr() at the end.
@vstinner vstinner removed the needs backport to 3.8 label now
I wrote a minimum fix for 3.8: PR #16623.
I may backport this change to 3.8, but only after the final 3.8.0 release. We can discuss that later ;-)
vstinner added a commit that referenced this pull request
bpo-36389, bpo-38376: The _PyObject_CheckConsistency() function is now also available in release mode. For example, it can be used to debug a crash in the visit_decref() function of the GC.
Modify the following functions to also work in release mode:
- _PyDict_CheckConsistency()
- _PyObject_CheckConsistency()
- _PyType_CheckConsistency()
- _PyUnicode_CheckConsistency()
Other changes:
- _PyMem_IsPtrFreed(ptr) now also returns 1 if ptr is NULL (equals to 0).
- _PyBytesWriter_CheckConsistency() now returns 1 and is only used with assert().
- Reorder _PyObject_Dump() to write safe fields first, and only attempt to render repr() at the end.
(cherry picked from commit 6876257)
Fix _PyBytesWriter API when Python is built in release mode with assertions.
(cherry picked from commit 60ec6ef)
subtract_refs() now pass the parent object to visit_decref() which pass it to _PyObject_ASSERT(). So if the "is freed" assertion fails, the parent is used in debug trace, rather than the freed object. The parent object is more likely to contain useful information. Freed objects cannot be inspected are are displayed as "" with no other detail.
(cherry picked from commit 4d5f94b)
Fix also a typo in PYMEM_DEADBYTE macro comment
bpo-36389: Add newline to _PyObject_AssertFailed() (GH-16629)
Add a newline between the verbose object dump and the Py_FatalError() logs for readability.
(cherry picked from commit 7775349)
jacobneiltaylor pushed a commit to jacobneiltaylor/cpython that referenced this pull request
bpo-36389, bpo-38376: The _PyObject_CheckConsistency() function is now also available in release mode. For example, it can be used to debug a crash in the visit_decref() function of the GC.
Modify the following functions to also work in release mode:
- _PyDict_CheckConsistency()
- _PyObject_CheckConsistency()
- _PyType_CheckConsistency()
- _PyUnicode_CheckConsistency()
Other changes:
- _PyMem_IsPtrFreed(ptr) now also returns 1 if ptr is NULL (equals to 0).
- _PyBytesWriter_CheckConsistency() now returns 1 and is only used with assert().
- Reorder _PyObject_Dump() to write safe fields first, and only attempt to render repr() at the end.