The `FDCapture`/`FDCaptureBinary` classes, used by `capfd`/`capfdbinary`
fixtures and the `--capture=fd` option (set by default), redirect FDs
1/2 (stdout/stderr) to a temporary file. To do this, they need to save
the old file by duplicating the FD before redirecting it, to be restored
once finished.
Previously, if this duplicating (`os.dup()`) failed, most likely due to
that FD being invalid, the FD redirection would silently not be done. The
FD capturing also performs python-level redirection (monkeypatching
`sys.stdout`/`sys.stderr`) which would still be done, but direct writes
to the FDs would fail.
This is not great. If pytest is run with `--capture=fd`, or a test is
using `capfd`, it expects writes to the FD to work and be captured,
regardless of external circumstances.
So, instead of disabling FD capturing, keep the redirection to a
temporary file, just don't restore it after closing, because there is
nothing to restore to.
This makes a difference for e.g. pytest-xdist:
Before:
```
--dist=distmode set mode for distributing tests to exec environments. each: …
available environment. loadscope: …
grouped by file to any available environment. (default) no: …
```
After:
```
--dist=distmode set mode for distributing tests to exec environments.
each: send each test to all available environments.
load: load balance by sending any pending test to any available environment.
…
(default) no: run tests inprocess, don't distribute.
```
This might also result in unexpected changes (hard wrapping), when line
endings where used unintentionally, e.g. with:
```
help="""
some long
help text
"""
```
But the benefits from that are worth it, and it is easy to fix, as will
be done for the internal `assertmode` option.
Currently, a bad logging call, e.g.
logger.info('oops', 'first', 2)
triggers the default logging handling, which is printing an error to
stderr but otherwise continuing.
For regular programs this behavior makes sense, a bad log message
shouldn't take down the program. But during tests, it is better not to
skip over such mistakes, but propagate them to the user.
Previously, a LoggingCaptureHandler was instantiated for each test's
setup/call/teardown which turns out to be expensive.
Instead, only keep one instance and reset it between runs.
The tests came via c629f6b18 and c61ff31ffa.
The fixes from there are kind of obsoleted by 4cd08f9 (moving to importlib),
but it makes sense to keep them as integration tests in general.
The logstart/logreport/logfinish hooks don't need the stuff in
_runtest_for. The test capturing catching_logs call is irrelevant for
them, and the item-conditional sections are gone.
- Instead of making it optional, always set up a handler, but possibly
going to /dev/null. This simplifies the code by removing a lot of
conditionals. It also can replace the NullHandler() we already add.
- Change `set_log_path` to just change the stream, instead of recreating
one. Besides plugging a resource leak, it enables the next item.
- Remove the capturing_logs from _runtest_for, since it sufficiently
covered by the one in pytest_runtestloop now, which wraps all other
_runtest_for calls.
The first item alone would have had an adverse performance impact, but
the last item removes it.
Remove usage of `@contextmanager` as it is a bit slower than
hand-rolling, and also disallows re-entry which we want to use.
Removing protections around addHandler()/removeHandler(), because
logging already checks that internally.
Conceptually it doesn't check per catching_logs (and catching_logs
doesn't restore the older one either). It is just something that is
defined for each handler once.
The default message is often hard to read:
E _pytest.config.ConftestImportFailure: (local('D:\\projects\\pytest\\.tmp\\root\\foo\\conftest.py'), (<class 'RuntimeError'>, RuntimeError('some error',), <traceback object at 0x000001CCC3E39348>))
Using a shorter message is better:
E _pytest.config.ConftestImportFailure: RuntimeError: some error (from D:\projects\pytest\.tmp\root\foo\conftest.py)
And we don't really lose any information due to exception chaining.
This removes the KeyError from the traceback chain when an
conftest fails to import:
return self._conftestpath2mod[key]
E KeyError: WindowsPath('D:/projects/pytest/.tmp/root/foo/conftest.py')
During handling of the above exception, another exception occurred:
...
raise RuntimeError("some error")
E RuntimeError: some error
During handling of the above exception, another exception occurred:
...
E _pytest.config.ConftestImportFailure: (...)
By slightly changing the code, we can remove the first chain, which is often
very confusing to users and doesn't help with anything.
Fix#7223
Ran Benita
Bruno Oliveira
mcsitter
Daniel Hahler
Katrin Leinweber
Anthony Sottile
Daniel Hahler