vim diff twopane

diffconflicts.sh

#!/bin/bash
# Instead of editing a file with  <<<< ==== >>> conflict markers, this opens
# each "side" of the conflict markers in a two-way vimdiff window.
#
# Layout:
#
#   Tab1 is a two-way diff of the conflicts.
#       +--------------------------------+
#       |    LCONFL     |    RCONFL      |
#       +--------------------------------+
#   Tab2 is a three-way diff of the original files and the merge base.
#       +--------------------------------+
#       |  LOCAL   |   BASE   |  REMOTE  |
#       +--------------------------------+
#   Tab3 is the MERGED or 'result' file that contains the conflict markers.
#       +--------------------------------+
#       |       <<<<<<< HEAD             |
#       |        LCONFL                  |
#       |       =======                  |
#       |        RCONFL                  |
#       |       >>>>>>> someref          |
#       +--------------------------------+
#
# Workflow:
#
# 1.    Save your changes to the LCONFL temporary file (the left window on the
#       first tab; also the only file that isn't read-only).
# 2.    The LOCAL, BASE, and REMOTE versions of the file are available in the
#       second tabpage if you want to look at them.
# 3.    When vimdiff exits cleanly, the file containing the conflict markers
#       will be updated with the contents of your LCONFL file edits.
#
# NOTE: Use :cq to abort the merge and exit Vim with an error code.
#
# Add this mergetool to your ~/.gitconfig (you can substitute vim for gvim):
#
# git config --global merge.tool diffconflicts
# git config --global mergetool.diffconflicts.cmd 'diffconflicts gvim $BASE $LOCAL $REMOTE $MERGED'
# git config --global mergetool.diffconflicts.trustExitCode true
# git config --global mergetool.diffconflicts.keepBackup false

if [[ -z $@ || $# != "5" ]] ; then
    echo -e "Usage: $0 \$BASE \$LOCAL \$REMOTE \$MERGED"
    exit 1
fi

cmd=$1
BASE=$2
LOCAL=$3
REMOTE=$4
MERGED=$5
LCONFL=$(dirname $5)/$$.left.tmp
RCONFL=$(dirname $5)/$$.right.tmp

# Remove the conflict markers for each 'side' and put each into a temp file
sed -e '/^=======$/,/>>>>>>>/d' -e '/<<<<<<</d' $MERGED > $LCONFL
sed -e '/<<<<<<</,/^=======$/d' -e '/>>>>>>>/d' $MERGED > $RCONFL

# Fire up vimdiff
$cmd -f -R -d $LCONFL $RCONFL \
    -c ":set noro" \
    -c ":tabe $LOCAL" -c ":vert diffs $BASE" -c ":vert diffs $REMOTE" \
    -c ":winc t" -c ":tabe $MERGED" -c ":tabfir"

EC=$?

# Overwrite $MERGED only if vimdiff exits cleanly.
if [[ $EC == "0" ]] ; then
    cat $LCONFL > $MERGED
fi

# Always delete our temp files; Git will handle it's own temp files
rm $LCONFL $RCONFL

exit $EC