Internal IndexError when testing

[solaluset]

I've encountered a strange IndexError when testing my package on GitHub Actions. It doesn't happen locally and only Python 3.11+ is affected.

pytest is 8.0.0, OS is ubuntu-20.04
Here's the log from the failed action: logs.txt

You can check my repository for details: https://github.com/solaluset/pwcp/tree/rename

[The-Compiler]

Relevant part of the logs:

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/main.py", line 272, in wrap_session
    session.exitstatus = doit(config, session) or 0
                         ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/main.py", line 326, in _main
    config.hook.pytest_runtestloop(session=session)
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_hooks.py", line 501, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_manager.py", line 119, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 138, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 121, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/logging.py", line 796, in pytest_runtestloop
    return (yield)  # Run all the tests.
            ^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 102, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/main.py", line 351, in pytest_runtestloop
    item.config.hook.pytest_runtest_protocol(item=item, nextitem=nextitem)
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_hooks.py", line 501, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_manager.py", line 119, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 138, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 121, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/warnings.py", line 109, in pytest_runtest_protocol
    return (yield)
            ^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 121, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/assertion/__init__.py", line 174, in pytest_runtest_protocol
    return (yield)
            ^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 121, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/unittest.py", line 408, in pytest_runtest_protocol
    res = yield
          ^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 121, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/faulthandler.py", line 85, in pytest_runtest_protocol
    return (yield)
            ^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 102, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/runner.py", line 114, in pytest_runtest_protocol
    runtestprotocol(item, nextitem=nextitem)
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/runner.py", line 133, in runtestprotocol
    reports.append(call_and_report(item, "call", log))
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/runner.py", line 228, in call_and_report
    report: TestReport = hook.pytest_runtest_makereport(item=item, call=call)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_hooks.py", line 501, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_manager.py", line 119, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 138, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 121, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/tmpdir.py", line 316, in pytest_runtest_makereport
    rep = yield
          ^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 121, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/skipping.py", line 269, in pytest_runtest_makereport
    rep = yield
          ^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/pluggy/_callers.py", line 102, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/runner.py", line 372, in pytest_runtest_makereport
    return TestReport.from_item_and_call(item, call)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/reports.py", line 364, in from_item_and_call
    longrepr = item.repr_failure(excinfo)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/python.py", line 1877, in repr_failure
    return self._repr_failure_py(excinfo, style=style)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/nodes.py", line 497, in _repr_failure_py
    return excinfo.getrepr(
           ^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/_code/code.py", line 698, in getrepr
    return fmt.repr_excinfo(self)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/_code/code.py", line 1057, in repr_excinfo
    reprtraceback = self.repr_traceback(excinfo_)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/_code/code.py", line 981, in repr_traceback
    entries = [
              ^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/_code/code.py", line 982, in <listcomp>
    self.repr_traceback_entry(entry, excinfo if last == entry else None)
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/_code/code.py", line 920, in repr_traceback_entry
    source = self._getentrysource(entry)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/_code/code.py", line 822, in _getentrysource
    source = entry.getsource(self.astcache)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/_code/code.py", line 259, in getsource
    astnode, _, end = getstatementrange_ast(
                      ^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/_pytest/_code/source.py", line 199, in getstatementrange_ast
    block_finder.started = source.lines[start][0].isspace()
                           ~~~~~~~~~~~~~~~~~~~^^^
IndexError: string index out of range

[solaluset]

This was because incomplete_input (python/cpython@cd6e0a0) was causing an error in my module. Still, pytest was of no help until I monkey patched it to check if the string actually contains something.

[bluetech]

I submitted a fix in #11996, maybe you can verify that it fixes the issue.

[solaluset]

@bluetech I confirm that it works