Bug 283250 – webkitcorepy.terminal.Terminal.override_atty rejects typing.IO subclasses

• Component: Tools / Tests
• Status: RESOLVED FIXED

[Sam Sneddon [:gsnedders]]

Trying to run the webkitscmpy tests under pytest leads to:

```
_____________________________________________________________ TestLog.test_git ______________________________________________________________

self = <webkitscmpy.test.log_unittest.TestLog testMethod=test_git>

    def test_git(self):
>       with OutputCapture() as captured, mocks.local.Git(self.path), mocks.local.Svn(), MockTime, Terminal.override_atty(sys.stdin, isatty=False):

webkitscmpy/test/log_unittest.py:43: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/contextlib.py:117: in __enter__
    return next(self.gen)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

cls = <class 'webkitcorepy.terminal.Terminal'>, target = <_pytest.capture.DontReadFromInput object at 0x1038de910>, isatty = False

    @classmethod
    @contextlib.contextmanager
    def override_atty(cls, target, isatty=True):
        if not isinstance(target, (io.IOBase, file, StringIO)):
>           raise ValueError('{} is not an IO object'.format(target))
E           ValueError: <_pytest.capture.DontReadFromInput object at 0x1038de910> is not an IO object

.tox/py39/lib/python3.9/site-packages/webkitcorepy/terminal.py:135: ValueError
```

_pytest.capture.DontReadFromInput:

In [2]: DontReadFromInput.__mro__
Out[2]: 
(_pytest.capture.DontReadFromInput,
 typing.TextIO,
 typing.IO,
 typing.Generic,
 object)

Thus it isn't an instance of any of the three classes we're checking for.

On the whole, this feels like somewhere where we shouldn't be doing runtime type-checking by default at all. At most, we should probably just be checking for some file-like protocol (having read/write), as there's plenty of file-like objects out there (even within the stdlib!).

[Sam Sneddon [:gsnedders]]

Pull request: https://github.com/WebKit/WebKit/pull/36766

[Radar WebKit Bug Importer]

<rdar://problem/140486513>

[EWS]

Committed 287299@main (c4740203d5ee): <https://commits.webkit.org/287299@main>

Reviewed commits have been landed. Closing PR #36766 and removing active labels.