[BUG] git-log shows first parent and repeated last for octopus merge

When trying to find how many merges and how many octopus merges (merges with more than two parents) are in git.git repository I have encountered the following strange output of git-log:

 1000:jnareb@roke:~/git> git log --parents --full-history --max-count=1 \
   211232bae64bcc60bbf5d1b5e5b2344c22ed767e -- a//b
 commit 211232bae64bcc60bbf5d1b5e5b2344c22ed767e <last parent repeated>
 Merge: d0d0d0b... d0d0d0b... d0d0d0b... d0d0d0b... d0d0d0b...
 [...]

while git-show gives correct output

 1005:jnareb@roke:~/git> git show 211232bae64bcc60bbf5d1b5e5b2344c22ed767e
 commit 211232bae64bcc60bbf5d1b5e5b2344c22ed767e
 Merge: fc54a9c... 9e30dd7... c4b83e6... 6602659... b28858b...
 [...]

Same with git-rev-list, also shows correct output:

 1005:jnareb@roke:~/git> git rev-list --header --parents --max-count=1 \
   211232bae64bcc60bbf5d1b5e5b2344c22ed767e
 211232bae64bcc60bbf5d1b5e5b2344c22ed767e [...] 
 tree cdafa88fa4ed7fcc7bb6c64d62e2d7c4d3b65e42
 parent fc54a9c30ccad3fde5890d2c0ca2e2acc0848fbc
 parent 9e30dd7c0ecc9f10372f31539d0122db97418353
 parent c4b83e618f1df7d8ecc9392fa40e5bebccbe6b5a
 parent 660265909fc178581ef327076716dfd3550e6e7b
 parent b28858bf65d4fd6d8bb070865518ec43817fe7f3
 [...]

1008:jnareb@roke:~/git> git --version git version 1.4.2.1

Hi,

On Wed, 18 Oct 2006, Jakub Narebski wrote:

This happens because a//b rewrites the history, i.e. the parents are edited. IMHO it makes no sense at all to show the parents in such a case, since they are bogus.

Ciao, Dscho

Johannes Schindelin wrote:

Or rather it has no sense to _repeat_ rewritten parent the number of times the commit has parents originally. Compare git-log and git-rev-list results:

1010:jnareb@roke:~/git> git rev-list --full-history --header --parents \
  --max-count=2 211232bae64bcc60bbf5d1b5e5b2344c22ed767e -- a//b
211232bae64bcc60bbf5d1b5e5b2344c22ed767e d0d0d0bd3c2c4591ffbc292d7e082e8ad8f2057f
tree cdafa88fa4ed7fcc7bb6c64d62e2d7c4d3b65e42
parent fc54a9c30ccad3fde5890d2c0ca2e2acc0848fbc
parent 9e30dd7c0ecc9f10372f31539d0122db97418353
parent c4b83e618f1df7d8ecc9392fa40e5bebccbe6b5a
parent 660265909fc178581ef327076716dfd3550e6e7b
parent b28858bf65d4fd6d8bb070865518ec43817fe7f3
author Junio C Hamano <junkio@cox.net> 1115335014 -0700
committer Junio C Hamano <junkio@cox.net> 1115335014 -0700

    Octopus merge of the following five patches.
    
      Update git-apply-patch-script for symbolic links.
      Make git-prune-script executable again.
      Do not write out new index if nothing has changed.
      diff-cache shows differences for unmerged paths without --cache.
      Update diff engine for symlinks stored in the cache.
    
    Signed-off-by: Junio C Hamano <junkio@cox.net>
d0d0d0bd3c2c4591ffbc292d7e082e8ad8f2057f 54c26fb9d0cdff94c7717125d0a222b324bfea8a
[...]

1014:jnareb@roke:~/git> PAGER= git log --full-history --parents \
  --max-count=2 211232bae64bcc60bbf5d1b5e5b2344c22ed767e -- a//b
commit 211232bae64bcc60bbf5d1b5e5b2344c22ed767e d0d0d0bd3c2c4591ffbc292d7e082e8ad8f2057f d0d0d0bd3c2c4591ffbc292d7e082e8ad8f2057f d0d0d0bd3c2c4591ffbc292d7e082e8ad8f2057f d0d0d0bd3c2c4591ffbc292d7e082e8ad8f2057f d0d0d0bd3c2c4591ffbc292d7e082e8ad8f2057f
Merge: d0d0d0b... d0d0d0b... d0d0d0b... d0d0d0b... d0d0d0b...
Author: Junio C Hamano <junkio@cox.net>
Date:   Thu May 5 16:16:54 2005 -0700

    Octopus merge of the following five patches.
    
      Update git-apply-patch-script for symbolic links.
      Make git-prune-script executable again.
      Do not write out new index if nothing has changed.
      diff-cache shows differences for unmerged paths without --cache.
      Update diff engine for symlinks stored in the cache.
    
    Signed-off-by: Junio C Hamano <junkio@cox.net>

commit d0d0d0bd3c2c4591ffbc292d7e082e8ad8f2057f 54c26fb9d0cdff94c7717125d0a222b324bfea8a 54c26fb9d0cdff94c7717125d0a222b324bfea8a [...]

Earlier, when calling

	git log --parents some-ref -- path/file

it was possible that in case of merges, multiple parents would be rewritten as the _same_ commit, which would happily be printed multiple times.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>

---

	Subject: Re: [BUG] git-log shows first parent and repeated last 
	for octopus merge

	On Wed, 18 Oct 2006, Jakub Narebski wrote:

	> Johannes Schindelin wrote:
	> > On Wed, 18 Oct 2006, Jakub Narebski wrote:
	> > 
	> > > When trying to find how many merges and how many octopus 
	> > > merges (merges with more than two parents) are in git.git 
	> > > repository I have encountered the following strange output 
	> > > of git-log:
	> > > 
	> > > 1000:jnareb@roke:~/git> git log --parents --full-history \
	> > > --max-count=1 211232bae64bcc60bbf5d1b5e5b2344c22ed767e -- a//b
	> > >  commit 211232bae64bcc60bbf5d1b5e5b2344c22ed767e <...>
	> > >  Merge: d0d0d0b... d0d0d0b... d0d0d0b... d0d0d0b... d0d0d0b...
	> > >  [...]
	> > 
	> > This happens because a//b rewrites the history, i.e. the 
	> > parents are edited. IMHO it makes no sense at all to show the 
	> > parents in such a case, since they are bogus.
	> 
	> Or rather it has no sense to _repeat_ rewritten parent the 
	> number of times the commit has parents originally.

	Here you are.

 revision.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

If the command line did not have --full-history, I would agree with you. The caller explicitly told us not to remove side branches that do not end up modifying the paths, and also told us, with --parent, to show parenthood information after removing intermediate commits that do not change the tree shape (with respect to the specified paths).

So it is showing what the user asked -- the user may not have understood what he was asking, but that is a separate problem, I would think.

Jakub Narebski wrote:

Maybe the following will find what you're looking for:

git-rev-list master --parents \
	|sed -e 's/[0-9a-f]\{40\}//' -e 's/ [0-9a-f]\{40\}/*/g' \
	|sort \
	|uniq -c