`test_pdb` broken under WASI

[brettcannon]

Bug report

#112109 is the culprit.

https://buildbot.python.org/all/#/builders/1046/builds/4033
https://buildbot.python.org/all/#/builders/1124/builds/623

Linked PRs

• gh-114275: Revert "gh-108303: Move all doctest related files and tests to Lib/test/test_doctest/ (#112109)" #114283
• gh-114275: Skip doctests that use asyncio in test_pdb for WASI builds #114309
• [3.11] gh-114275: Skip doctests that use asyncio in test_pdb for WASI builds (GH-114309) #114438
• [3.12] gh-114275: Skip doctests that use asyncio in test_pdb for WASI builds (GH-114309) #114439

[brettcannon]

/cc @sobolevn

[sobolevn]

Hm, I am investigating this 🤔

First of all, it passes locally on macos platform.

Second, here's the failure:

Doctest: test.test_pdb.test_pdb_next_command_for_coroutine ... FAIL
test_pdb_next_command_for_generator (test.test_pdb)
Doctest: test.test_pdb.test_pdb_next_command_for_generator ... ok
test_pdb_next_command_in_generator_for_loop (test.test_pdb)
Doctest: test.test_pdb.test_pdb_next_command_in_generator_for_loop ... ok
test_pdb_next_command_subiterator (test.test_pdb)
Doctest: test.test_pdb.test_pdb_next_command_subiterator ... ok
test_pdb_pp_repr_exc (test.test_pdb)
Doctest: test.test_pdb.test_pdb_pp_repr_exc ... Warning -- Unraisable exception
Exception ignored in: <function BaseEventLoop.__del__ at 0xb453f8>
Traceback (most recent call last):
  File "/Lib/asyncio/base_events.py", line 750, in __del__
    self.close()
  File "/Lib/asyncio/unix_events.py", line 70, in close
    super().close()
  File "/Lib/asyncio/selector_events.py", line 104, in close
    self._close_self_pipe()
  File "/Lib/asyncio/selector_events.py", line 111, in _close_self_pipe
    self._remove_reader(self._ssock.fileno())
AttributeError: '_UnixSelectorEventLoop' object has no attribute '_ssock'
Warning -- Unraisable exception
Exception ignored in: <function BaseEventLoop.__del__ at 0xb453f8>
Traceback (most recent call last):
  File "/Lib/asyncio/base_events.py", line 750, in __del__
    self.close()
  File "/Lib/asyncio/unix_events.py", line 70, in close
    super().close()
  File "/Lib/asyncio/selector_events.py", line 104, in close
    self._close_self_pipe()
  File "/Lib/asyncio/selector_events.py", line 111, in _close_self_pipe
    self._remove_reader(self._ssock.fileno())
AttributeError: '_UnixSelectorEventLoop' object has no attribute '_ssock'
ok
test_pdb_return_command_for_coroutine (test.test_pdb)
Doctest: test.test_pdb.test_pdb_return_command_for_coroutine ... FAIL

Third, no direct import / usage of test_doctest is there.
Looking further.

[sobolevn]

Ok, I found out what is going on:

1. test_pdb used to import code from test_doctest
2. test_doctest has if not support.has_subprocess_support: skip
3. So, all test_pdb was skipped on wasi, proof: https://buildbot.python.org/all/#/builders/1061/builds/694/steps/11/logs/stdio
4. Now, I removed import from test_doctest, which is a good thing
5. It unskipped test_pdb on WASI

There are several things we can do:

1. Skip these failing tests on WASI with a TODO comment
2. Skip the whole test file
3. Try to fix it (but it is asyncio related and I am not an expert in this module)

I propose to use the same skip that test_asyncio uses for these specific tests.

@brettcannon @vstinner what are your thoughts on this?