git-svn-diff.sh

#!/bin/bash

set -e

#receipt http://stackoverflow.com/questions/14062895/bash-argument-case-for-args-in/14063511#14063511
while [[ $# -gt 0 ]] && [[ ."$1" = .--* ]]; do
    optname="$1";
    shift;              #expose next argument

    case "$optname" in
        "--" ) break 2;;
        "--staged")
            STAGED=true
            ;;
        *)
            echo "Unknown option $optname while processing options"
            exit 1
            ;;
    esac
done

# Get the tracking branch (if we're on a branch)
SVN_BRANCH=`git svn info | grep URL | sed -e 's/.*\/branches\///'`

if [[ "$SVN_BRANCH" =~ URL.* ]]; then
        SVN_BRANCH=`git svn info | grep URL | sed -e 's/.*\/release-branches\///'`
fi
 
# If the tracking branch has 'URL' at the beginning, then the sed wasn't successful and
# we'll fall back to the svn-remote config option
if [[ "$SVN_BRANCH" =~ URL.* ]]; then
        SVN_BRANCH=`git config --get svn-remote.svn.fetch | sed -e 's/.*:refs\/remotes\///'`
fi

REV=`git svn find-rev $(git rev-list --date-order --max-count=1 remotes/$SVN_BRANCH)`

TRACKING_BRANCH=`git rev-parse --abbrev-ref HEAD`

lf=$'\n'
tab=$'\t'

GIT_REVISION_FILTER=''
if [ $STAGED ]; then
    GIT_REVISION_FILTER='--staged'
else 
    GIT_REVISION_FILTER="$(git rev-list --date-order --max-count=1 $TRACKING_BRANCH)"
fi

git diff --no-prefix $GIT_REVISION_FILTER |
sed "
# New files have /dev/null as their original path
/^--- \/dev\/null/{
    # Read a line into the pattern space
    N
    # Do a multiline substitution
    s/^--- \/dev\/null\n+++ \(.*\)$/--- \1\\${tab}(revision 0)\\${lf}+++ \1\\${tab} (working copy)/
    # Jump to the end of the script. This skips the next two substitutions
    b end
}
s/^+++ .*/&\\${tab}(working copy)/
s/^--- .*/&\\${tab}(revision $REV)/
s/^diff --git [^[:space:]]*/Index:/
s/^index.*/===================================================================/
: end
"