Re: gitweb: buggy 'commitdiff_plain' output

On Fri, Jul 10, 2009 at 7:04 PM, Linus
Torvalds[off-list ref] wrote:

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 [off-list ref]
   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 [off-list ref]
       Reviewed-by: Christoph Hellwig [off-list ref]
       Signed-off-by: Steve French [off-list ref]

    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.

The smarter way is called the 'patches' ('patch' for single ones, e.g.
http://git.example.com/project.git/patch/master, whereas /patches/
would display the latest N with N configurable) view that just spouts
out the git format-patch output in a git-am friendly way. I'm pretty
sure my patches to implement that view are already upstream ... yes,
yes it is:

http://git.oblomov.eu/git/patches/9872cd..75bf2cb2

To understand the differences between this and commitdiff_plain, see

http://git.oblomov.eu/git/commitdiff_plain/9872cd..75bf2cb2

for comparison.

And yes, commitdiff is just TOTALLY not what you expect it to be,
ESPECIALLY with multiple commits, where it only displays the commit
message for the FIRST commit.

So tell the CIFS people to use the patch(es) view if they plan to use
gitweb for patch exchange (which I do all the time, and in fact was
the reason why I implemented this view in the first place).

-- 
Giuseppe "Oblomov" Bilotta