PyStructSequence_NewType() not setting proper heap allocation flag?

[WolfIhlenfeldt]

BPO	20066
Nosy	@serhiy-storchaka, @corona10, @nanjekyejoannah

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2019-12-27.02:24:56.818>
created_at = <Date 2013-12-25.13:33:19.572>
labels = ['interpreter-core', 'type-crash']
title = 'PyStructSequence_NewType() not setting proper heap allocation flag?'
updated_at = <Date 2019-12-27.02:24:56.815>
user = 'https://bugs.python.org/WolfIhlenfeldt'

bugs.python.org fields:

activity = <Date 2019-12-27.02:24:56.815>
actor = 'corona10'
assignee = 'none'
closed = True
closed_date = <Date 2019-12-27.02:24:56.818>
closer = 'corona10'
components = ['Interpreter Core']
creation = <Date 2013-12-25.13:33:19.572>
creator = 'Wolf.Ihlenfeldt'
dependencies = []
files = []
hgrepos = []
issue_num = 20066
keywords = []
message_count = 4.0
messages = ['206923', '231331', '352501', '358896']
nosy_count = 4.0
nosy_names = ['serhiy.storchaka', 'Wolf.Ihlenfeldt', 'corona10', 'nanjekyejoannah']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue20066'
versions = ['Python 3.4', 'Python 3.5']

[WolfIhlenfeldt]

If I am not mistaken, I think that PyStructSequence_NewType() should set the Py_TPFLAGS_HEAPTYPE flag in tp->flags (which it currently does not). The original version initially works fine, but ultimately crashes at exit time in finalization with

Fatal Python error: type_traverse() called for non-heap type 'E_FILE'

#0 0x00007ffff12913d5 in raise () from /lib64/libc.so.6
#1 0x00007ffff1292858 in abort () from /lib64/libc.so.6
#2 0x00007ffff2360484 in Py_FatalError (msg=<optimized out>) at Python/pythonrun.c:2364
#3 0x00007ffff22e5354 in type_traverse (type=0x10b47a0, visit=0x7ffff2374350 <visit_decref>, arg=0x0)
at Objects/typeobject.c:2892
#4 0x00007ffff2374bd1 in subtract_refs (containers=0x7ffff26466c0) at Modules/gcmodule.c:386
#5 collect (n_uncollectable=<synthetic pointer>, n_collected=<synthetic pointer>, generation=2)
at Modules/gcmodule.c:891
#6 collect_with_callback (generation=2) at Modules/gcmodule.c:1048
#7 0x00007ffff2375436 in PyGC_Collect () at Modules/gcmodule.c:1476
#8 0x00007ffff235f698 in Py_Finalize () at Python/pythonrun.c:521
#9 0x00007ffff6e70b70 in CSpythonFinalize () at nmds_python.c:44652
#10 0x0000000000407399 in main ()

Setting the flag manually after creation lets the problem disappear.

[serhiy-storchaka]

See also bpo-15729.

[nanjekyejoannah]

As commented in bpo-15729, the Py_TPFLAGS_HEAPTYPE flag is now set in PyType_FromSpecWithBases() which is called by PyStructSequence_NewType(). I think this is no longer an issue.

[corona10]

Thanks @nanjekyejoannah for comment.

Yes, I found that the codes are updated.
see

cpython/Objects/structseq.c

Line 488 in bd44a7e

type = (PyTypeObject *)PyType_FromSpecWithBases(&spec, bases);

I close this issue.