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co_instrumentation and co_monitoring Unexpectedly Set #133524
Description
Bug report
Bug description:
I ran into the following problematic case with gh-133221 (which had to be reverted):
import sys
import _testinternalcapi
def foo():
pass
def trace_temporarily():
sys._getframe().f_trace_opcodes = True
sys.settrace(print)
sys.settrace(None)
sys._getframe().f_trace_opcodes = False
trace_temporarily()
_testinternalcapi.verify_stateless_code(foo.__code__)
foo()
_testinternalcapi.verify_stateless_code(foo.__code__) # fails(See #133221 (comment).)
I would expect co_instrumentation and co_monitoring to have remained NULL.
CC @markshannon
CPython versions tested on:
CPython main branch
Operating systems tested on:
No response
Activity
[-]co_instrumentation Unexpectedly Set[/-][+]co_instrumentation and co_monitoring Unexpectedly Set[/+]gaogaotiantian commentedon May 6, 2025
The root cause for this is that flipping
f_trace_opcodeschanges the global version of instrumentation. Therefore a new function being called allocates the instrumentation data to get up to date.I think we can do an optimization here by checking if any event is set globally - if not, don't bother allocating the instrumentation memory. If @markshannon thinks this is something we should do, I can do it.