#!/bin/bash
#
# Custom Git merge driver - merges PO files using msgcat(1)
#
# To use this,
#  git config merge.pofile.name "Gettext merge driver"
#  git config merge.pofile.driver "src/po/git-merge-po %O %A %B"
#
# - When merging branches, conflicts in PO files will be maked with "#-#-#-#"
#
set -x
O="$1"
A="$2"
B="$3"

# Extract the PO header from the current branch (top of file until first empty line)
header="$(mktemp /tmp/merge-po.XXXX)"
sed -e '/^$/q' < "$A" > "$header"

# Merge files, then repair header
temp="$(mktemp /tmp/merge-po.XXXX)"
msgcat -o "$temp" "$A" "$B"
msgcat --use-first -o "$A" "$header" "$temp"

# Clean up
rm "$header" "$temp"

# Check for conflicts
conflicts=$(grep -c "#-#" "$A")
test "$conflicts" -gt 0 && exit 1
exit 0