git-commit-vandalism/git-merge-one-file-script

#!/bin/sh
#
# This is the git merge script, called with
#
#   $1 - original file SHA1 (or empty)
#   $2 - file in branch1 SHA1 (or empty)
#   $3 - file in branch2 SHA1 (or empty)
#   $4 - pathname in repository
#   $5 - orignal file mode (or empty)
#   $6 - file in branch1 mode (or empty)
#   $7 - file in branch2 mode (or empty)
#
# Handle some trivial cases.. The _really_ trivial cases have
# been handled already by git-read-tree, but that one doesn't
# do any merges that migth change the tree layout.

case "${1:-.}${2:-.}${3:-.}" in
#
# Deleted in both.
#
"$1..")
	echo "ERROR: $4 is removed in both branches."
	echo "ERROR: This is a potential rename conflict."
	exit 1;;
#
# Deleted in one and unchanged in the other.
#
"$1.." | "$1.$1" | "$1$1.")
	echo "Removing $4"
	exec git-update-cache --force-remove "$4" ;;
#
# Added in one.
#
".$2." | "..$3" )
	case "$6$7" in *7??) mode=+x;; *) mode=-x;; esac
	echo "Adding $4 with perm $mode."
	exec git-update-cache --add --cacheinfo "$6$7" "$2$3" "$4" ;;
#
# Added in both (check for same permissions).
#
".$3$2")
	if [ "$6" != "$7" ]; then
		echo "ERROR: File $4 added identically in both branches,"
		echo "ERROR: but permissions conflict $6->$7."
		exit 1
	fi
	case "$6" in *7??) mode=+x;; *) mode=-x;; esac
	echo "Adding $4 with perm $mode"
	exec git-update-cache --add --cacheinfo "$6" "$2" "$4" ;;
#
# Modified in both, but differently.
#
"$1$2$3")
	echo "Auto-merging $4."
	orig=`git-unpack-file $1`
	src1=`git-unpack-file $2`
	src2=`git-unpack-file $3`
	merge "$src2" "$orig" "$src1"
	ret=$?
	if [ "$6" != "$7" ]; then
		echo "ERROR: Permissions $5->$6->$7 don't match."
	fi
	if [ $ret -ne 0 ]; then
		echo "ERROR: Leaving conflict merge in $src2."
		exit 1
	fi
	sha1=`git-write-blob "$src2"` || {
		echo "ERROR: Leaving conflict merge in $src2."
	}
	exec git-update-cache --add --cacheinfo "$6" $sha1 "$4" ;;
*)
	echo "ERROR: Not handling case $4: $1 -> $2 -> $3" ;;
esac
exit 1