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Bug 1340036

Summary: argparse set_defaults precedence changed
Product: Red Hat Enterprise Linux 7 Reporter: Marek Haicman <mhaicman>
Component: pythonAssignee: Charalampos Stratakis <cstratak>
Status: CLOSED WONTFIX QA Contact: BaseOS QE - Apps <qe-baseos-apps>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 7.2CC: cstratak, jkejda, pviktori, torsava
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
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Last Closed: 2016-07-04 13:14:39 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description Flags
reproducer none

Description Marek Haicman 2016-05-26 10:57:18 UTC
Created attachment 1161894 [details]
reproducer

Description of problem:
There was probably a change in behaviour of python argparse in upstream. RHEL versions currently do not behave the same way, which is possibly causing problems during inclusion of upstreams into RHEL.

In RHEL versions, parser.set_defaults takes precedence to subparser.set_defaults. This priority is reversed in newer versions.

Version-Release number of selected component (if applicable):
python-2.7.5

How reproducible:
reliably

Steps to Reproduce:
1. python argparse_defaults.py a
2. see output


Actual results:
In RHEL, outputs "parser"

Expected results:
In newer versions of python, for example 2.7.10, or 3.4.3, outputs "subparser_a"

Comment 2 Marek Haicman 2016-05-26 11:39:35 UTC
Upstream patch changing the behaviour:
https://hg.python.org/cpython/rev/1a3143752db2

Related upstream issue/discussion:
http://bugs.python.org/issue9351#msg244786

Comment 3 Petr Viktorin (pviktori) 2016-06-21 12:16:09 UTC
This would change behavior of existing software that uses argparse, and there are reports of such brokennes in the upstream issue. How can we ensure there will be no regressions?

Unfortunately, I fear this will need to be handled in new software that is getting into RHEL.