Something I’ve wanted to do for a while is get the list of changed files and a diff into the commit message in my editor when I make a commit with Subversion.

With Git, you can pass the -v (verbose) option when committing, and the commit message you edit will include diffs as well as the list of modified files.

Subversion provides no such option, so I put together a little wrapper shell script to do this for me.

The script provides a function named svncommit (which I alias to just ‘ci’ for supreme shortness :) ).

When used, after the “–This line, and those below, will be ignored–” marker line, the list of files and then diffs will be inserted, as shown in the screenshot below (click for full size):

The script itself is relatively simple (it was knocked up quickly; I’ll probably improve on it sometime):

# Do an svn commit, with diffs included in the commit message
svncommit() {

    # Start preparing the commit message which we'll then edit
    COMMITMSG=/tmp/$USER-commitmsg
    echo > $COMMITMSG
    echo "--This line, and those below, will be ignored--" >> $COMMITMSG
    svn status "$@" >> $COMMITMSG
    echo >> $COMMITMSG

    # Now do a diff; work out stats on lines added/removed by looking at
    # the diff, add that info, then the diff itself
    svn diff "$@"   > /tmp/$USER-svndiff
    LINESADDED=$(  grep '^+[^+]' /tmp/$USER-svndiff | wc -l)
    LINESREMOVED=$(grep '^-[^-]' /tmp/$USER-svndiff | wc -l)
    echo "Added $LINESADDED lines, removed $LINESREMOVED lines" >> $COMMITMSG
    echo >> $COMMITMSG
    cat /tmp/$USER-svndiff >> $COMMITMSG
    echo >> $COMMITMSG

    ORIGMD5=$(md5sum $COMMITMSG)
    $VISUAL $COMMITMSG

    if [[ "$(md5sum $COMMITMSG)" == "$ORIGMD5" ]]; then
        echo "Commit message unchanged, commit aborted";
    else
        svn commit "$@" -F $COMMITMSG
    fi

    rm $COMMITMSG
    rm /tmp/$USER-svndiff
}