git-svn-diff.sh

#!/bin/bash
#
# git-svn-diff originally by (http://mojodna.net/2009/02/24/my-work-git-workflow.html)
# modified by mike@mikepearce.net
# modified by aconway@[redacted] - handle diffs that introduce new files
# modified by t.broyer@ltgt.net - fixes diffs that introduce new files
# modified by m@rkj.me - fix sed syntax issue in OS X
#
# Generate an SVN-compatible diff against the tip of the tracking branch

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

# 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 [[ "$TRACKING_BRANCH" =~ URL.* ]]
then
        TRACKING_BRANCH=`git config --get svn-remote.svn.fetch | sed -e 's/.*:refs\/remotes\///'`
fi

# Get the highest revision number
REV=`git svn find-rev $(git rev-list --date-order --max-count=1 $TRACKING_BRANCH)`

# Then do the diff from the highest revision on the current branch 
# and masssage into SVN format
git diff --no-prefix $(git rev-list --date-order --max-count=1 $TRACKING_BRANCH) $* |
sed -e "/--- \/dev\/null/{ N; s|^--- /dev/null\n+++ \(.*\)|---\1	(revision 0)\n+++\1	(revision 0)|;}" \
    -e "s/^--- .*/&	(revision $REV)/" \
    -e "s/^+++ .*/&	(working copy)/" \
    -e "s/^diff --git [^[:space:]]*/Index:/" \
    -e "s/^index.*/===================================================================/"

The reason it doesn't handle new files correctly is because of the first line of the sed command not adding a space between ---/+++ and \1.

See https://gist.github.com/rage-shadowman/6325382 for an updated version of this which gives identical output (in all of my tests so far) to svn diff.

Seems the script doesn't take chmod messages into account...
new file mode 100755

on my laptop(osx 10.10.3) sed doesn't write newline ('\n') correctly.

change the line #27

sed -e "/--- \/dev\/null/{ N; s|^--- /dev/null\n+++ \(.*\)|---\1    (revision 0)\n+++\1 (revision 0)|;}" \

to

sed -e '/^--- \/dev\/null/{ N; s|^--- /dev/null\n+++ \(.*\)|---\1   (revision 0)\
+++\1   (revision 0)|;}' \

that is, change double quote to single quote and replace the '\n' by a backslash followed by a newline character.
fixes it.

Thanks for the script!

Also found that (revision ...) sticks to the path, so the latter is incorrect.

--- -e "s/^--- .*/&(revision $REV)/" \
+++ -e "s/^--- .*/& (revision $REV)/" \

A whitespace is needed