ResourceWarning: unclosed file <_io.TextIOWrapper name='/dev/null' mode='r' encoding='UTF-8'> #4355
Description
I've seen the following on full run of the test suite:
============== 1 failed, 2270 passed, 83 skipped, 13 xfailed in 271.31 seconds ==============
Exception ignored in: <_io.FileIO name='/dev/null' mode='rb' closefd=True>
ResourceWarning: unclosed file <_io.TextIOWrapper name='/dev/null' mode='r' encoding='UTF-8'>
Exception ignored in: <_io.FileIO name=13 mode='rb+' closefd=True>
ResourceWarning: unclosed file <_io.FileIO name=13 mode='rb+' closefd=True>
Exception ignored in: <_io.FileIO name=15 mode='rb+' closefd=True>
ResourceWarning: unclosed file <_io.FileIO name=15 mode='rb+' closefd=True>
Exception ignored in: <_io.FileIO name='/dev/null' mode='rb' closefd=True>
ResourceWarning: unclosed file <_io.TextIOWrapper name='/dev/null' mode='r' encoding='UTF-8'>
Exception ignored in: <_io.FileIO name=19 mode='rb+' closefd=True>
ResourceWarning: unclosed file <_io.FileIO name=19 mode='rb+' closefd=True>
Exception ignored in: <_io.FileIO name=21 mode='rb+' closefd=True>
ResourceWarning: unclosed file <_io.FileIO name=21 mode='rb+' closefd=True>
Related to #3879 in that it would be nice if those would cause CI to fail.
I have not investigated what triggered them.
This was on 8baeb90.