GH-113486: Do not emit spurious PY_UNWIND events for optimized calls to classes.

[markshannon]

Adds the CO_NO_MONITORING_EVENTS flag for use by shim frame code objects and similar, to avoid monitoring events.

• Issue: Coverage.py test suite fails on 3.13 (since June?) #113486

[nedbat]

Thanks for the quick action. I took the liberty of testing this branch. The events reported to the settrace function is changed:

import linecache, sys

def trace(frame, event, arg):
    # The weird globals here is to avoid a NameError on shutdown...
    if frame.f_code.co_filename == globals().get("__file__"):
        lineno = frame.f_lineno
        line = linecache.getline(__file__, lineno).rstrip()
        print("{} {}: {}".format(event[:4], lineno, line))
    return trace

print(sys.version)
sys.settrace(trace)

def gen():
    print(2)
    yield 3
    print(4)

print(next(gen()))

Running with 3.12:

3.12.1 (main, Dec  8 2023, 20:58:19) [Clang 15.0.0 (clang-1500.0.40.1)]
call 14: def gen():
line 15:     print(2)
2
line 16:     yield 3
retu 16:     yield 3
call 16:     yield 3
exce 16:     yield 3
retu 16:     yield 3
3

Running with this branch:

3.13.0a2+ (heads/pr/113680:e92fd7b816, Jan  4 2024, 10:22:55) [Clang 15.0.0 (clang-1500.1.0.2.5)]
call 14: def gen():
line 15:     print(2)
2
line 16:     yield 3
retu 16:     yield 3
3

Do you mean to skip the return and call events from the yield?

[nedbat]

BTW, the 3.13 behavior also happens with 3.13.0a2, so it's not due to the change in this branch, but seems related?

3.13.0a2 (main, Nov 24 2023, 14:53:47) [Clang 15.0.0 (clang-1500.0.40.1)]
call 14: def gen():
line 15:     print(2)
2
line 16:     yield 3
retu 16:     yield 3
3

[markshannon]

@nedbat
I've opened #113728 for the difference between 3.12 and 3.13.

[gaogaotiantian]

Sorry I was traveling and did not have a reliable network access. But the change looks good to me.