Re: [PATCH] fmt-merge-msg: avoid open "-|" list form for Perl 5.6

Linus Torvalds [off-list ref] writes:

For example, afaik, when merging multiple branches that had partially been 
merged already (ie they had overlapping new stuff), if I read the old perl 
code correctly, it would talk about the new stuff multiple times. This one 
doesn't.

I think this is not quite right, even though it only matters in
Octopus and not many people do Octopus anyway.  Suppose you are
merging lt/rev-list and fk/blame branches into master, starting
from this state:

    ! [master] GIT-VERSION-GEN: squelch unneed
     ! [lt/rev-list] setup_revisions(): handle
      ! [fk/blame] git-blame, take 2
    ---
     +  [lt/rev-list] setup_revisions(): handl
     +  [lt/rev-list^] git-log (internal): mor
     +  [lt/rev-list~2] git-log (internal): ad
      + [fk/blame] git-blame, take 2
      - [fk/blame^] Merge part of 'lt/rev-list
     ++ [lt/rev-list~3] Rip out merge-order an
     ++ [lt/rev-list~4] Tie it all together: "
     ++ [lt/rev-list~5] Introduce trivial new 
     ++ [lt/rev-list~6] git-rev-list libificat
     ++ [lt/rev-list~7] Splitting rev-list int
     ++ [lt/rev-list~8] rev-list split: minimu
     ++ [lt/rev-list~9] First cut at libifying
      + [fk/blame~2] Add git-blame, a tool for
    --- [lt/rev-list~10] Merge branch 'maint' 

And you had lt/rev-list branch first listed in FETCH_HEAD.  In
this particular example, lt/rev-list has only 3 commits on top
of common things, but if your max were 3 instead of 10, the
first round would actually show the tip 3 without showing any
common stuff, and then the next round to show fk/blame branch
would show only the remaining two, without ever showing the
common stuff, even though it _could_ say the latest of the
common stuff.

The things it doesn't do:
 - the old one had a limit of 20, the new one has a limit of 10 commits 
   reported

Good change I would say, except for the above.

 - the old one was tested, the new one is written by me.
 - the old one honored the "merge.summary" git config option. The new one 
   doesn't.

Easily rectifiable ;-).

 - the old one did some formatting of the branch message that I don't 
   follow because I'm not a perl user. The new one just takes the 
   explanatory message for the branch merging as-is.

FETCH_HEAD has explanatory message in more or less "canonical"
form.  It has noise word "branch", and the current repository is
typically " of .".  These are removed by the code, so that you would
not have to see:

	Merge branch 'jc/delta' of .

Instead you would see:

	Merge 'jc/delta' into 'next'.

The last part, " into 'next'", is also missing from your
version.  I can distinguish a merge into 'master' (which does
not have " into 'master'") and other branches easily that way,
and I find it handy.

Other things the Perl code does are purely for Octopus support:
things like coalescing multiple branches taken from the same
repositories.  You would get something like:

	Merge 'lt/rev-list' and 'fk/blame' into 'next'.

	* lt/rev-list:
	  commit 1
          commit 2

	* fk/blame:
	  commit 3
	  commit 4

instead of (your version):

	Merge branch 'lt/rev-list' of .
	   * commit 1
           * commit 2

	Merge branch 'fk/blame' of .
	   * commit 3
           * commit 4