In order to allow users to type annotate fixtures they request, the
types need to be imported from the `pytest` namespace. They are/were
always available to import from the `_pytest` namespace, but that is
not guaranteed to be stable.
These types are only exported for the purpose of typing. Specifically,
the following are *not* public:
- Construction (`__init__`)
- Subclassing
- staticmethods and classmethods
We try to combat them being used anyway by:
- Marking the classes as `@final` when possible (already done).
- Not documenting private stuff in the API Reference.
- Using `_`-prefixed names or marking as `:meta private:` for private
stuff.
- Adding a keyword-only `_ispytest=False` to private constructors,
warning if False, and changing pytest itself to pass True. In the
future it will (hopefully) become a hard error.
Hopefully that will be enough.
We want to export `pytest.MonkeyPatch` for the purpose of
type-annotating the `monkeypatch` fixture. For other fixtures we export
in this way, we also make direct construction of them (e.g.
`MonkeyPatch()`) private. But unlike the others, `MonkeyPatch` is also
widely used directly already, mostly because the `monkeypatch` fixture
only works in `function` scope (issue #363), but also in other cases. So
making it private will be annoying and we don't offer a decent
replacement yet.
So, let's just make direct construction public & documented.
Running `pytest | head -1` and similar causes an annoying error to be
printed to stderr:
Exception ignored in: <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'>
BrokenPipeError: [Errno 32] Broken pipe
(or possibly even a propagating exception in older/other Python versions).
The standard UNIX behavior is to handle the EPIPE silently. To
recommended method to do this in Python is described here:
https://docs.python.org/3/library/signal.html#note-on-sigpipe
It is not appropriate to apply this recommendation to `pytest.main()`,
which is used programmatically for in-process runs. Hence, change
pytest's entrypoint to a new `pytest.console_main()` function, to be
used exclusively by pytest's CLI, and add the SIGPIPE code there.
Fixes#4375.
ExitCode is used in several internal modules and hooks and so with type
annotations added, needs to be imported a lot.
_pytest.main, being the entry point, generally sits at the top of the
import tree.
So, it's not great to have ExitCode defined in _pytest.main, because it
will cause a lot of import cycles once type annotations are added (in
fact there is already one, which this change removes).
Move it to _pytest.config instead.
_pytest.main still imports ExitCode, so importing from there still
works, although external users should really be importing from `pytest`.
Ran Benita
Manuel Mariñez
Maximilian Cosmo Sitter
Bruno Oliveira
Ronny Pfannschmidt
earonesty
Bruno Oliveira