with capsys.disabled() causes "I/O operation on closed file"

[brechtm]

Sphinx.build() fails if contained in a capsys.disabled() context manager:

tests_regression/test_sphinxdocs.py:45: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
.tox/regression/lib/python3.5/site-packages/sphinx/application.py:296: in build
    self.builder.compile_update_catalogs()
.tox/regression/lib/python3.5/site-packages/sphinx/builders/__init__.py:205: in compile_update_catalogs
    self.compile_catalogs(catalogs, message)
.tox/regression/lib/python3.5/site-packages/sphinx/builders/__init__.py:166: in compile_catalogs
    self.info(bold('building [mo]: ') + message)
.tox/regression/lib/python3.5/site-packages/sphinx/application.py:370: in info
    self._log(message, self._status, nonl)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
self = <sphinx.application.Sphinx object at 0x7f701dde1588>
message = '\x1b[01mbuilding [mo]: \x1b[39;49;00mtargets for 0 po files that are out of date'
wfile = <_io.StringIO object at 0x7f701ef41b88>, nonl = False
    def _log(self, message, wfile, nonl=False):
        try:
>           wfile.write(message)
E           ValueError: I/O operation on closed file
.tox/regression/lib/python3.5/site-packages/sphinx/application.py:322: ValueError

Full log: https://travis-ci.org/brechtm/rinohtype/jobs/155119487

Running the tests with the -s flag instead of the context manager works fine.

[nicoddemus]

Thanks for the report.

Did this worked in a previous version? Could please you post a reproducible example?

[The-Compiler]

Did this worked in a previous version?

capsys.disabled() was added in 3.0 (by that guy with a penguin avatar) 😉

[nicoddemus]

capsys.disabled() was added in 3.0 (by that guy with a penguin avatar)

Duh 😅

@brechtm I see you are constructing the sphinx object outside the with statement:

sphinx = Sphinx(...)
with capsys.disabled();
    sphinx.build()

Try construct the sphinx object inside the with statement to see if it helps:

with capsys.disabled();
    sphinx = Sphinx(...)
    sphinx.build()

I suspect the error is happening because some code is opening and keeping a reference to a log file somewhere, and capsys.disabled() closes that file to restore the original stdin. If that's the case and the above suggestion does not work, I'm afraid there's nothing that can be done on our side.

[brechtm]

Nope, the problem persists if I make the instantiation part of the context. It does work, however, if I also move the import statement to the content:

with capsys.disabled():
    from sphinx.application import Sphinx
    sphinx = Sphinx(...)
    sphinx.build()

Which might indicate some nasty trickery going on in the Sphinx modules, indeed :-)

[nicoddemus]

It is probably setting up a logger at module level, which is actually the usual approach to logging.

I think we can close this as there is nothing that can be done on Pytest's side. Feel free to reopen if you still want to discuss something or have other questions. 😁