pytest has several instances where plugins set their own attributes on
objects they receive in hooks, like nodes and config. Since plugins are
detached from these object's definition by design, this causes a problem
for type checking because these attributes are not defined and mypy
complains.
Fix this by giving these objects a "store" which can be used by plugins
in a type-safe manner.
Currently this mechanism is private. We can consider exposing it at a
later point.
Mypy currently is unable to handle assigning attributes on function:
https://github.com/python/mypy/issues/2087.
pytest uses this for the outcome exceptions -- `pytest.fail.Exception`,
`pytest.exit.Exception` etc, and this is the canonical name by which they
are referred.
Initially we started working around this with type: ignores, and later
by switching e.g. `pytest.fail.Exception` with the direct exception
`Failed`. But this causes a lot of churn and is not as nice. And I also
found that some code relies on it, in skipping.py:
def pytest_configure(config):
if config.option.runxfail:
# yay a hack
import pytest
old = pytest.xfail
config._cleanup.append(lambda: setattr(pytest, "xfail", old))
def nop(*args, **kwargs):
pass
nop.Exception = xfail.Exception
setattr(pytest, "xfail", nop)
...
So it seems better to support it. Use a hack to make it work. The rest
of the commit rolls back all of the workarounds we added up to now.
`pytest.raises.Exception` also exists, but it's not used much so I kept
it as-is for now.
Hopefully in the future mypy supports this and this ugliness can be
removed.
Everything was using `_pytest.compat.getfslineno` basically, which
wrapped `_pytest._code.source.getfslineno`.
This moves the extra code from there into it directly, and uses the
latter everywhere.
This helps to eventually remove the one in compat eventually, and also
causes less cyclic imports.
This allows for e.g. Jedi to infer types (it checks the name).
It was only used to support Python 3.5.0/3.5.1, where this is is not
available in the `typing` module.
Ref: https://github.com/davidhalter/jedi/issues/1472
Uses `TYPE_CHECKING = False` in `_pytest.outcomes` to avoid having to
work around circular import.
This is a useful utility to abstract the caching property idiom.
It is in compat.py since eventually it will be replaced by
functools.cached_property.
Fixes#6131.
Add a very lax mypy configuration, add it to tox -e linting, and
fix/ignore the few errors that come up. The idea is to get it running
before diving in too much.
This enables:
- Progressively adding type annotations and enabling more strict
options, which will improve the codebase (IMO).
- Annotating the public API in-line, and eventually exposing it to
library users who use type checkers (with a py.typed file).
Though, none of this is done yet.
Refs https://github.com/pytest-dev/pytest/issues/3342.
Ref: https://github.com/pytest-dev/pytest/issues/4321#issuecomment-436951894
Hardens some of the not many tests affected by this:
1. `testing/test_session.py::test_rootdir_option_arg` displayed:
> root/test_rootdir_option_arg2/test_rootdir_option_arg.py
2. `test_cmdline_python_namespace_package` displayed "hello/" prefix for:
> hello/test_hello.py::test_hello
> hello/test_hello.py::test_other