Small bug in doctest framework's mapping of Python 2 exception classes to Python 3 exceptions

[embray]

The doctest framework has some built-in mappings of built-in exception classes from their Python 2 spellings to their Python 3, so that doctests that expect those exceptions can be raised can be written for Python 2 but still work on Python 3: #25676

There is at least one case where the current implementation of this fails. See: #26213 comment:22

CC: @fchapoton

Component: python3

Reviewer: Matthias Koeppe, Frédéric Chapoton

Issue created by migration from https://trac.sagemath.org/ticket/26244

[embray]

comment:1

If you would like to take a stab at it. Otherwise I'll fix it. It's just a question of slightly rearranging this code in sage.doctest.forker:

 702                     else:
 703                         # Special case: On Python 3 these exceptions are all
 704                         # just aliases for OSError
 705                         for alias in _OSError_ALIASES:
 706                             if example.exc_msg.startswith(alias + ':'):
 707                                 exc_msg = exc_msg.replace('OSError', alias, 1)
 708                                 break
 709                         else:
 710                             for subcls in _OSError_SUBCLASSES:
 711                                 if exc_msg.startswith(subcls + ':'):
 712                                     exc_msg = exc_msg.replace(subcls, 'OSError',
 713
 714                                                               1)
 715                                     break

[embray]

comment:3

Retargeting some of my tickets (somewhat optimistically for now).

[embray]

comment:4

Removing most of the rest of my open tickets out of the 8.7 milestone, which should be closed.

[mkoeppe]

comment:5

outdated?

[fchapoton]

comment:6

ok

[slel]

Reviewer: Matthias Koeppe, Frédéric Chapoton