[New-bugs-announce] [issue33154] subprocess.Popen ResourceWarning should have activation-deactivation flags

[Arno-Can Uestuensoez]

New submission from Arno-Can Uestuensoez <acue.opensource at gmail.com>:

The subprocess call *subprocess.Popen* in Python3.6 was added a number of resource warnings, including subprocess run-state and open files. This is a very good facility for debugging, but causes a lot of trouble for programs relying on subprocesses via the STDIO/STDERR interface. The STDIO/STDERR interfaces are very common when shell utilities are incorporated into high level Python programs.

The other issue is the unit testing of command line tools as black-box tests, these solely rely on the STDOUT and STDERR interface. I am currently finishing a subprocess test package with common code for Python2.7 and Python3.5+, so facing some trouble with IO filtering. Examples are attached.

A system call should process the common IO interfaces of the called subprocesses by default without any additional output. So a call flag and/or an environment variable should be introduced in addition, which allows the activation and deactivation of these messages.
The default should be *deactive*.

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components: Library (Lib)
files: python3-output.txt
messages: 314511
nosy: acue, martin.panter, pitrou, python-dev, serhiy.storchaka, vstinner
priority: normal
severity: normal
status: open
title: subprocess.Popen ResourceWarning should have activation-deactivation flags
type: resource usage
versions: Python 3.6
Added file: https://bugs.python.org/file47502/python3-output.txt

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<https://bugs.python.org/issue33154>
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