pytest: DeprecationWarning for imp module triggered when run with -Werror

Testing with -Werror is convenient for CI testing so that warnings can be quickly identified and corrected rather than staying dormant.

With Python 3.5.1 if you execute with -Werror you receive a PendingDeprecationWarning because imp has been deprecated since Python 3.4.

Edit: As of Python 3.6 this is now a full DeprecationWarning.

The code causing the issue is:

https://github.com/pytest-dev/pytest/blob/ecc5c84c1ec77ad43f0fe0cb34a097bb855c1423/src/_pytest/assertion/rewrite.py#L8

To reproduce:

$ python -Werror -m pytest test.py

Traceback (most recent call last):
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\runpy.py", line 170, in _run_module_as_main
    "__main__", mod_spec)
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\site-packages\pytest.py", line 16, in <module>
    import pytest
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\site-packages\pytest.py", line 27, in <module>
    _preloadplugins() # to populate pytest.* namespace so help(pytest) works
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\site-packages\_pytest\config.py", line 75, in _preloadplugins
    _preinit.append(get_config())
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\site-packages\_pytest\config.py", line 84, in get_config
    pluginmanager.import_plugin(spec)
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\site-packages\_pytest\config.py", line 384, in import_plugin
    __import__(importspec)
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\site-packages\_pytest\main.py", line 6, in <module>
    import os, sys, imp
  File "C:\Users\John Hagen\AppData\Local\Programs\Python\Python35\lib\imp.py", line 33, in <module>
    PendingDeprecationWarning, stacklevel=2)
PendingDeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses

$ pip -V
pip 8.0.2
$ pip list
...
pytest (2.8.7)

This was tested on Windows 10 x64.

About this issue

Original URL
State: closed
Created 8 years ago
Reactions: 6
Comments: 18 (10 by maintainers)

Commits related to this issue

Merge #86 86: Update pytest to 5.0.1 r=rehandalal a=pyup-bot This PR updates [pytest](https://pypi.org/project/pytest) from **4.6.3** to **5.0.1**. <details> <summary>Changelog</summary> ... — committed to rehandalal/therapist by bors[bot] 5 years ago
Merge #32 32: Pin pytest to latest version 5.1.3 r=duckinator a=pyup-bot This PR pins [pytest](https://pypi.org/project/pytest) to the latest release **5.1.3**. <details> <summary>Changelog</s... — committed to duckinator/bork by bors[bot] 5 years ago
Ovverriding DeprecationWarning for the imp module https://github.com/pytest-dev/pytest/issues/1403 — committed to artynet/sphinx by artynet 4 years ago
Ovverriding DeprecationWarning for the imp module https://github.com/pytest-dev/pytest/issues/1403 — committed to artynet/sphinx by artynet 4 years ago
Merge #1 1: Initial Update r=aragilar a=pyup-bot This PR sets up pyup.io on this repo and updates all dependencies at once, in a single branch. Subsequent pull requests will update one dependency... — committed to aragilar/pytest-info-collector by bors[bot] 4 years ago
Merge #1 1: Initial Update r=aragilar a=pyup-bot This PR sets up pyup.io on this repo and updates all dependencies at once, in a single branch. Subsequent pull requests will update one dependency... — committed to aragilar/spaceplot by bors[bot] 4 years ago
Merge #1 1: Initial Update r=aragilar a=pyup-bot This PR sets up pyup.io on this repo and updates all dependencies at once, in a single branch. Subsequent pull requests will update one dependency... — committed to aragilar/venv_tools by bors[bot] 4 years ago
Merge #5 5: Initial Update r=aragilar a=pyup-bot This PR sets up pyup.io on this repo and updates all dependencies at once, in a single branch. Subsequent pull requests will update one dependency... — committed to aragilar/root-solver by bors[bot] 4 years ago

Most upvoted comments

Shouldn’t this stay open until the compatibility layer mentioned by @nicoddemus is introduced?

With

This is pytest version 3.2.2, imported from /usr/lib64/python3.6/site-packages/pytest.py
setuptools registered plugins:
  pytest-timeout-1.2.0 at /usr/lib64/python3.6/site-packages/pytest_timeout.py
  pytest-pep8-1.0.6 at /usr/lib64/python3.6/site-packages/pytest_pep8.py
  pytest-cov-2.5.1 at /usr/lib64/python3.6/site-packages/pytest_cov/plugin.py

_pytest/assertion/rewrite.py uses the imp module, triggering the following warning on every run of one of my programs:

/usr/lib64/python3.6/site-packages/_pytest/assertion/rewrite.py:7: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
  import imp

which I think is annoying enough to at least leave the report open 😉?

+13

leezu on Oct 3, 2017

With Python 3.6, we will get the following warning instead of PendingDeprecationWarning:

DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/local/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/local/lib/python3.6/site-packages/pytest.py", line 9, in <module>
    from _pytest.config import (
  File "/usr/local/lib/python3.6/site-packages/_pytest/config.py", line 18, in <module>
    import _pytest.assertion
  File "/usr/local/lib/python3.6/site-packages/_pytest/assertion/__init__.py", line 9, in <module>
    from _pytest.assertion import rewrite
  File "/usr/local/lib/python3.6/site-packages/_pytest/assertion/rewrite.py", line 6, in <module>
    import imp
  File "/usr/local/lib/python3.6/imp.py", line 33, in <module>
    DeprecationWarning, stacklevel=2)
DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses

(tested with Python 3.6.5 (python:3.6-alpine3.7 Docker image))

+10

tnir on May 29, 2018

The most narrow way of suppressing this I’ve been able to find is:

$ python -Werror -Wignore:::_pytest.assertion.rewrite -m pytest test.py

This will suppress all warnings in _pytest.assertion.rewrite, which is arguably a little brittle if pytest refactors internally but at least it avoids having to globally disable all DeprecationWarnings and miss the opportunity to catch the use of deprecated items in user code.

Having this fixed in pytest would still be very ideal and would allow downstream users to use -Werror in a much more straightforward way.

johnthagen on Dec 2, 2018

@marchfra you can choose to suppress them in pytest:

# pytest.ini
[pytest]
filterwarnings =
    error
    ignore::UserWarning

or additionally update the dependency if it has been updated since inline with pending deprecations

symonk on Jan 7, 2021

For anyone else who wants to run with warnings as errors: in Hypothesis we found that there are too many warnings in tools to make environment-wide -Werror (let alone PYTHONWARNINGS=error) practical.

Instead, we configure warnings in conftest.py:

import warnings
warnings.simplefilter('error')

Zac-HD on Apr 20, 2018