gitweb: buggy 'commitdiff_plain' output

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jul 10, 2009, 17:04 UTC
Message-ID: <alpine.LFD.2.01.0907100941060.3352@localhost.localdomain>

I complained to the CIFS people about their crazy duplicated commit message headers: see for example

    [torvalds@nehalem linux]$ git show --stat aeaaf253c4dee7ff9af2f3f0595f3bb66964e944
    commit aeaaf253c4dee7ff9af2f3f0595f3bb66964e944
    Author: Jeff Layton <jlayton@redhat.com>
    Date:   Thu Jul 9 01:46:39 2009 -0400
    
        cifs: remove cifsInodeInfo->inUse counter
        
        cifs: remove cifsInodeInfo->inUse counter
        
        It was purported to be a refcounter of some sort, but was never
        used that way. It never served any purpose that wasn't served equally well
        by the I_NEW flag.
        
        Signed-off-by: Jeff Layton <jlayton@redhat.com>
        Reviewed-by: Christoph Hellwig <hch@lst.de>
        Signed-off-by: Steve French <sfrench@us.ibm.com>
    
     fs/cifs/cifsfs.c   |    1 -
     fs/cifs/cifsglob.h |    1 -
     2 files changed, 0 insertions(+), 2 deletions(-)

and note the duplicated "cifs: remove cifsInodeInfo->inUse counter" line.

It turns out that that duplication is because they use gitweb as a strange patch distribution system (rather than emailing each other patches), and download the 'commitdiff_plain' version of the diff and then apply it with 'git am -s'.

Ok, so it's a really odd way of doing things, but hey, that gitweb feature clearly does try to support that exact workflow, or why would that commitdiff_plain output try to look like an email?

But gitweb is a totally buggy piece of trash when it comes to exporting commits that way.

Why? Because it first has a 'Subject:' line, and then the "body" of the email repeats the raw commit message output. So _of_course_ you get the header duplicated.

Now, I asked Steve to not use gitweb (or edit the result some way), but this really is a gitweb bug. And since I don't do perl, I can't fix it, even though I can pinpoint exactly where the bug is (lines 5732 - 5752 in gitweb/gitweb.perl).

I totally untested patch written by a monkey who doesn't actually do perl is appended as a purely theoretical pointer in the right direction. But I really have no clue about perl, so what the heck do I know? This is like my tcl programming - pattern matching rather than any real understanding.

I'm sure there are smarter ways to do this with some simple mapping function or whatever.

		Linus

---
 gitweb/gitweb.perl |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 6a1b5b5..a809768 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -5729,6 +5729,7 @@ sub git_commitdiff {
 		}
 
 	} elsif ($format eq 'plain') {
+		my $show = false;
 		my $refs = git_get_references("tags");
 		my $tagname = git_get_rev_name_tags($hash);
 		my $filename = basename($project) . "-$hash.patch";
@@ -5747,7 +5748,11 @@ sub git_commitdiff {
 		print "X-Git-Url: " . $cgi->self_url() . "\n\n";
 
 		foreach my $line (@{$co{'comment'}}) {
-			print to_utf8($line) . "\n";
+			if ($show) {
+				print to_utf8($line) . "\n";
+			} else if ($line ne "") {
+				$show = true;
+			}
 		}
 		print "---\n\n";
 	} elsif ($format eq 'patch') {