Bug 186027

Summary:	filterdiff filename match is unpredictable
Product:	[Fedora] Fedora	Reporter:	Rik van Riel <riel>
Component:	patchutils	Assignee:	Tim Waugh <twaugh>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	8	CC:	triage
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:	bzcl34nup
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2008-06-16 08:31:17 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	236808

Description Rik van Riel 2006-03-21 04:08:20 UTC

Description of problem:

When trying to build a script to filter certain parts out of a series of
patches, the behaviour of filterdiff is unpredictable.

Instead of simply picking the file name after +++ (new file name) as the key for
-x and -i, filterdiff choses the shorter of the two file names.  This makes it
impossible to use eg. the output from diffstat for constructing an exclude list.

To make things worse, this behaviour appears to be undocumented.

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

patchutils-0.2.31-2.2.1

Expected results:

The filenames that filterdiff works on should correspond to the ones shown in
diffstat output.  Yes, I know these are different packages, but they're used
together all the time and having one of the tools exhibit such an unpredictable
behaviour is a problem.

Comment 1 Tim Waugh 2007-10-31 13:31:11 UTC

The algorithm that filterdiff/lsdiff uses is the one described in the patch(1)
man page:

       To determine the best of a nonempty list of  file  names,  patch  first
       takes  all the names with the fewest path name components; of those, it
       then takes all the names with the shortest basename; of those, it  then
       takes  all  the  shortest  names; finally, it takes the first remaining
       name.

However, I take your point that this can make -x and -i rather difficult to use
in conjuction with other programs that use different rules.

How are you invoking diffstat to get a parseable list of filenames to
exclude/include?  Really -x and -i were designed with lsdiff/grepdiff output in
mind.

Comment 2 Bug Zapper 2008-04-03 17:09:54 UTC

Based on the date this bug was created, it appears to have been reported
against rawhide during the development of a Fedora release that is no
longer maintained. In order to refocus our efforts as a project we are
flagging all of the open bugs for releases which are no longer
maintained. If this bug remains in NEEDINFO thirty (30) days from now,
we will automatically close it.

If you can reproduce this bug in a maintained Fedora version (7, 8, or
rawhide), please change this bug to the respective version and change
the status to ASSIGNED. (If you're unable to change the bug's version
or status, add a comment to the bug and someone will change it for you.)

Thanks for your help, and we apologize again that we haven't handled
these issues to this point.

The process we're following is outlined here:
http://fedoraproject.org/wiki/BugZappers/F9CleanUp

We will be following the process here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping to ensure this
doesn't happen again.

Comment 3 Tim Waugh 2008-04-03 17:15:13 UTC

There's been no code change, so this is still an issue.

Comment 4 Tim Waugh 2008-06-16 08:31:17 UTC

Seems like '-p1' (for example) will do what you want in the majority of cases.