Incorrect line number calculated in traceback

Consider the following code:

def _run_with_file_output():
    example_report_generation_message= (
            """
            """
    ).strip()
    raise ValueError()

_run_with_file_output()

If you execute this with 3.11.0a7 you get (correct traceback):

Traceback (most recent call last):
  File "/home/pablogsal/github/python/3.11/lel.py", line 8, in <module>
    _run_with_file_output()
    ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pablogsal/github/python/3.11/lel.py", line 6, in _run_with_file_output
    raise ValueError()
    ^^^^^^^^^^^^^^^^^^
ValueError

but on 3.11.0b1 you get:

Traceback (most recent call last):
  File "/home/pablogsal/github/python/3.11/lel.py", line 8, in <module>
    _run_with_file_output()
    ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pablogsal/github/python/3.11/lel.py", line 255, in _run_with_file_output
ValueError

Notice that the last line number for _run_with_file_output is wrong (255 instead of 6).

Bisecting points at:

944fffee8916cb94321fa33cd3a43f4108717746 is the first bad commit
commit 944fffee8916cb94321fa33cd3a43f4108717746
Author: Mark Shannon <mark@hotpy.org>
Date:   Thu Apr 21 16:10:37 2022 +0100

    GH-88116: Use a compact format to represent end line and column offsets. (GH-91666)

    * Stores all location info in linetable to conform to PEP 626.

    * Remove column table from code objects.

    * Remove end-line table from code objects.

    * Document new location table format

@godlygeek

Originally noticed by @godlygeek

Notice that if you change the input to be:

def _run_with_file_output():
    _= (
            """
            """
    ).strip()
    raise ValueError()

_run_with_file_output()

Then the line numbers and the tracebacks are correct (likely due to the difference in column offset):

Traceback (most recent call last):
  File "/home/pablogsal/github/python/3.11/lel.py", line 8, in <module>
    _run_with_file_output()
    ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pablogsal/github/python/3.11/lel.py", line 6, in _run_with_file_output
    raise ValueError()
    ^^^^^^^^^^^^^^^^^^
ValueError

May be related to #93249

It looks like the table is correct, but the parsing to get the line number is wrong.
.__code__.co_positions() shows the correct positions, but .__code__.co_lines() shows the wrong line numbers.

It's actually a bug in compiler front-end. It produces an instruction with lineno == end_lineno but end_col_offset < col_offset

#93673

GH-93662: Make sure that column offsets are correct in multi-line met…

pythonGH-93662: Make sure that column offsets are correct in multi-li…

Backport to 3.11: #93895

[3.11] GH-93662: Make sure that column offsets are correct in multi-l…

Revert 30935 defer bpo45162 to 312 (#94285)

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Incorrect line number calculated in traceback #93662

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Incorrect line number calculated in traceback #93662

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pablogsal commented on Jun 9, 2022

pablogsal commented on Jun 9, 2022

pablogsal commented on Jun 9, 2022

markshannon commented on Jun 10, 2022

markshannon commented on Jun 10, 2022

markshannon commented on Jun 10, 2022

iritkatriel commented on Jun 16, 2022

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