Bug 186027 - filterdiff filename match is unpredictable
filterdiff filename match is unpredictable
Product: Fedora
Classification: Fedora
Component: patchutils (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Tim Waugh
Depends On:
Blocks: F7Update
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Reported: 2006-03-20 23:08 EST by Rik van Riel
Modified: 2008-06-16 04:31 EDT (History)
1 user (show)

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Doc Type: Bug Fix
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Last Closed: 2008-06-16 04:31:17 EDT
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Description Rik van Riel 2006-03-20 23:08:20 EST
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):


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 09:31:11 EDT
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

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
Comment 2 Bug Zapper 2008-04-03 13:09:54 EDT
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against rawhide during the development of a Fedora release that is no
longer maintained.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:

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 13:15:13 EDT
There's been no code change, so this is still an issue.
Comment 4 Tim Waugh 2008-06-16 04:31:17 EDT
Seems like '-p1' (for example) will do what you want in the majority of cases.

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