From: Jeff King <peff@peff.net>
Date: Wed, 21 Nov 2007 11:27:57 GMT
Subject: Re: Using Filemerge.app as a git-diff viewer
Message-ID: <20071121112757.GA17231@sigill.intra.peff.net>
In-Reply-To: <47440912.8010800@cam.ac.uk>

On Wed, Nov 21, 2007 at 10:31:46AM +0000, Toby White wrote:

> So I wrote a quick script (below) which does what I need. Of all
> the available git-diff flags, it only understands "--cached", and
> up to two commit objects, and no paths, but that's enough for me.
> Within those constraints, it has the same semantics as git-diff.

Have you looked at the documentation for GIT_EXTERNAL_DIFF (try git(7))?
I think it is a cleaner way of doing what you want (although I think you
will get each file diffed individually, which is perhaps not what you
want).

Something like:

$ cat >merge.sh <<EOF
#!/bin/sh
opendiff "$1" "$2"
EOF
$ GIT_EXTERNAL_DIFF=./merge.sh git-diff ...

> #!/bin/sh
> #
> # Filemerge.app must not already be open before running
> # this script, or opendiff below will return immediately,
> # and the TMPDIRs deleted before it gets the chance to read
> # them.
>
> if test $# = 0; then
>   OLD=`git-write-tree`
> elif test "$1" = --cached; then
>   OLD=HEAD
>   NEW=`git-write-tree`
>   shift
> fi
> if test $# -gt 0; then
>   OLD="$1"; shift
> fi
> test $# -gt 0 && test -z "$CACHED" && NEW="$1"

write-tree? Yikes. If you want to diff against the working tree, then do
that. If you want to diff against the index, then you probably want to
git-checkout-index to a tmpdir, and diff against that.

> git-archive --format=tar $OLD | (cd $TMPDIR1; tar xf -)

Again, this could be simpler and faster by using git-checkout-index
(preceded by git-read-tree into a temp index, if you are comparing
against a tree).

-Peff