pygit2 segfault under pytest

[RazerM]

• Include a detailed description of the bug or suggestion
  I have a test that causes a segfault when run with pytest, but doesn't when run by python. It happens when passing an empty temporary directory to pygit2.Repository.

# works fine
python3 test_pygit2.py

# segfault
python3 -X faulthandler -m pytest test_pygit2.py

• pip list of the virtual environment you are using

Package       Version
------------- -------
attrs         17.4.0
cffi          1.11.5
pip           9.0.1
pkg-resources 0.0.0
pluggy        0.6.0
py            1.5.2
pycparser     2.18
pygit2        0.26.3
pytest        3.4.2
setuptools    32.3.1
six           1.11.0

• pytest and operating system versions
  • macOS 10.12.6
  • Debian buster (so it has the same libgit2 that I have on my mac)
  • pytest 3.4.2
• Minimal example if possible

File test_pygit.py:

from pygit2 import Repository
import tempfile

def test_segfault():
    with tempfile.TemporaryDirectory() as tmpdir:
        Repository(tmpdir)

if __name__ == '__main__':
    test_segfault()

running under pytest:

# python3 -X faulthandler -m pytest test_pygit2.py
=================================== test session starts ===================================
platform linux -- Python 3.6.4+, pytest-3.2.5, py-1.5.2, pluggy-0.4.0
rootdir: /, inifile:
collected 1 item

test_pygit2.py Fatal Python error: Segmentation fault

Current thread 0x00007f1f2a1e6740 (most recent call first):
  File "/usr/lib/python3/dist-packages/pygit2/repository.py", line 100 in __repr__
  File "/usr/lib/python3/dist-packages/py/_io/saferepr.py", line 38 in _callhelper
  File "/usr/lib/python3/dist-packages/py/_io/saferepr.py", line 33 in repr_instance
  File "/usr/lib/python3.6/reprlib.py", line 65 in repr1
  File "/usr/lib/python3.6/reprlib.py", line 55 in repr
  File "/usr/lib/python3/dist-packages/py/_io/saferepr.py", line 38 in _callhelper
  File "/usr/lib/python3/dist-packages/py/_io/saferepr.py", line 13 in repr
  File "/usr/lib/python3/dist-packages/py/_io/saferepr.py", line 71 in saferepr
  File "/usr/lib/python3/dist-packages/_pytest/_code/code.py", line 497 in _saferepr
  File "/usr/lib/python3/dist-packages/_pytest/_code/code.py", line 503 in repr_args
  File "/usr/lib/python3/dist-packages/_pytest/_code/code.py", line 580 in repr_traceback_entry
  File "/usr/lib/python3/dist-packages/_pytest/_code/code.py", line 621 in repr_traceback
  File "/usr/lib/python3/dist-packages/_pytest/_code/code.py", line 669 in repr_excinfo
  File "/usr/lib/python3/dist-packages/_pytest/_code/code.py", line 435 in getrepr
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 477 in _repr_failure_py
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 576 in _repr_failure_py
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 583 in repr_failure
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 303 in pytest_runtest_makereport
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 614 in execute
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 265 in __init__
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 248 in _wrapped_call
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 613 in execute
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 334 in <lambda>
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 339 in _hookexec
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 745 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 159 in call_and_report
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 77 in runtestprotocol
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 63 in pytest_runtest_protocol
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 614 in execute
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 265 in __init__
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 248 in _wrapped_call
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 613 in execute
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 265 in __init__
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 248 in _wrapped_call
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 613 in execute
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 334 in <lambda>
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 339 in _hookexec
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 745 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 170 in pytest_runtestloop
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 614 in execute
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 334 in <lambda>
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 339 in _hookexec
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 745 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 147 in _main
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 111 in wrap_session
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 140 in pytest_cmdline_main
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 614 in execute
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 334 in <lambda>
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 339 in _hookexec
  File "/usr/lib/python3/dist-packages/_pytest/vendored_packages/pluggy.py", line 745 in __call__
  File "/usr/lib/python3/dist-packages/_pytest/config.py", line 58 in main
  File "/usr/lib/python3/dist-packages/pytest.py", line 73 in <module>
  File "/usr/lib/python3.6/runpy.py", line 85 in _run_code
  File "/usr/lib/python3.6/runpy.py", line 193 in _run_module_as_main
Segmentation fault

running under python, with correct exception:

# python3 test_pygit2.py
Traceback (most recent call last):
  File "test_pygit2.py", line 9, in <module>
    test_segfault()
  File "test_pygit2.py", line 6, in test_segfault
    Repository(tmpdir)
  File "/venv/lib/python3.6/site-packages/pygit2/repository.py", line 1184, in __init__
    path_backend = init_file_backend(path)
_pygit2.GitError: Repository not found at /tmp/tmp_9_aoab1

I'm assuming this is a pytest error since it works when called from Python, but if that's wrong I can file this against pygit2.

[pytestbot]

GitMate.io thinks possibly related issues are #1411 (Pytest stops), #1602 (pytest.print()), #2838 (Contributing to pytest-dev), #1370 (Print out pytest-warnings?), and #528 (Test causes segfault).

[RonnyPfannschmidt]

whats the output if the test is not running under pytest?

its possible that pygit2 does something that breaks pytests capture mechanism

[RazerM]

@RonnyPfannschmidt I have added the output to the main post

[RonnyPfannschmidt]

based on the posted information its unclear whats at fault here

[RazerM]

Ok so Repository.__repr__ is being called by pytest before Repository.__init__ returns, and the C getter for Repository.path tries to use self->repo which isn't initialized. It's a pygit2 bug.

[RonnyPfannschmidt]

thanks for following up with the details 👍