[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Ned Batchelder]

Change by Ned Batchelder :


--
stage: patch review -> resolved
status: open -> closed

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Mark Shannon]

Mark Shannon  added the comment:

Ned, can I close this?

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Mark Shannon]

Change by Mark Shannon :


--
pull_requests: +22978
stage: resolved -> patch review
pull_request: https://github.com/python/cpython/pull/24150

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Ned Batchelder]

Ned Batchelder  added the comment:

OK, thanks.  I guess the parallels between the Python frame object and the C 
frame object made it easy to think I could use the fields directly.  I'm 
updating the coverage.py code.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Mark Shannon]

Mark Shannon  added the comment:

It looks like you are accessing the c field "f_lineno" directly.
That was never guaranteed to work, it just happened to.
You should use PyFrame_GetLineNumber()
If "f_lineno" is up to date, then it will be almost efficient as the direct 
field access (the overhead is a C call).
If "f_lineno" is not up to date, PyFrame_GetLineNumber() will compute the 
correct value.

In the interest of efficiency it makes sense that the internal f_line field is 
updated before CALL and RETURN trace events.
I'll make that change, but you really ought to use the API rather than probing 
into the frame internals.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Ned Batchelder]

Ned Batchelder  added the comment:

This change seems like it has caused a problem.  Python trace functions behave 
as they did in Python 3.9, but C trace functions no longer get line numbers for 
call or return events.


Running this test code:

def gen(inp):
for n in inp:
yield n

list(gen([1,2,3]))

With my C trace function logging what it is passed, in Python 3.9 I got this:

trace: CALL @ coverage_test_2616437928787223.py 1
trace: LINE @ coverage_test_2616437928787223.py 1
trace: LINE @ coverage_test_2616437928787223.py 5
trace: CALL @ coverage_test_2616437928787223.py 1
trace: LINE @ coverage_test_2616437928787223.py 2
trace: LINE @ coverage_test_2616437928787223.py 3
trace: RET  @ coverage_test_2616437928787223.py 3
trace: CALL @ coverage_test_2616437928787223.py 3
trace: LINE @ coverage_test_2616437928787223.py 2
trace: LINE @ coverage_test_2616437928787223.py 3
trace: RET  @ coverage_test_2616437928787223.py 3
trace: CALL @ coverage_test_2616437928787223.py 3
trace: LINE @ coverage_test_2616437928787223.py 2
trace: LINE @ coverage_test_2616437928787223.py 3
trace: RET  @ coverage_test_2616437928787223.py 3
trace: CALL @ coverage_test_2616437928787223.py 3
trace: LINE @ coverage_test_2616437928787223.py 2
trace: RET  @ coverage_test_2616437928787223.py 2
trace: RET  @ coverage_test_2616437928787223.py 5

With 3.10 (commit 1a9f51ed12feb4d95ad6d0faf610a030c05b9f5e) I get:

trace: CALL @ coverage_test_40117094849631774.py 0
trace: LINE @ coverage_test_40117094849631774.py 1
trace: LINE @ coverage_test_40117094849631774.py 5
trace: CALL @ coverage_test_40117094849631774.py 0
trace: LINE @ coverage_test_40117094849631774.py 2
trace: LINE @ coverage_test_40117094849631774.py 3
trace: RET  @ coverage_test_40117094849631774.py 0
trace: CALL @ coverage_test_40117094849631774.py 0
trace: LINE @ coverage_test_40117094849631774.py 2
trace: LINE @ coverage_test_40117094849631774.py 3
trace: RET  @ coverage_test_40117094849631774.py 0
trace: CALL @ coverage_test_40117094849631774.py 0
trace: LINE @ coverage_test_40117094849631774.py 2
trace: LINE @ coverage_test_40117094849631774.py 3
trace: RET  @ coverage_test_40117094849631774.py 0
trace: CALL @ coverage_test_40117094849631774.py 0
trace: LINE @ coverage_test_40117094849631774.py 2
trace: RET  @ coverage_test_40117094849631774.py 0
trace: RET  @ coverage_test_40117094849631774.py 0

All of the call and return events now get a frame with f_lineno == 0.

Python trace functions seem unaffected.

The C code producing this debug output is here: 
https://github.com/nedbat/coveragepy/blob/a498ebc28273fd21b6a047a173b2e4443b91f563/coverage/ctracer/tracer.c#L786-L813

--
nosy: +nedbat
status: closed -> open

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Mark Shannon]

Change by Mark Shannon :


--
resolution:  -> fixed
stage: patch review -> resolved
status: open -> closed

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Mark Shannon]

Mark Shannon  added the comment:


New changeset ee9f98d9f4b881ee15868a836a2b99271df1bc0e by Mark Shannon in 
branch 'master':
bpo-42823: Fix frame lineno when frame.f_trace is set (GH-24099)
https://github.com/python/cpython/commit/ee9f98d9f4b881ee15868a836a2b99271df1bc0e


--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Mark Shannon]

Change by Mark Shannon :


--
keywords: +patch
pull_requests: +22930
stage:  -> patch review
pull_request: https://github.com/python/cpython/pull/24099

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue42823] Incorrect frame.f_lineno when frame.f_trace is set

[Mark Shannon]

New submission from Mark Shannon :

The logic for frame.f_lineno assumes that the internal C field will be updated 
when f_trace is set, but that is incorrect.
Consequently, the following code

import sys

def print_line():
print(sys._getframe(1).f_lineno)

def test():
print_line()
sys._getframe(0).f_trace = True
print_line()
print_line()

test()

prints
7
8
8

it should print
7
9
10


Fixing this is required by PEP 626, but it should be fixed anyway.

--
assignee: Mark.Shannon
messages: 384331
nosy: Mark.Shannon
priority: normal
severity: normal
status: open
title: Incorrect frame.f_lineno when frame.f_trace is set

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com