1 files changed, 166 insertions, 0 deletions
diff --git a/git-revert.sh b/git-revert.sh
new file mode 100755
index 0000000000..722c4f755a
--- /dev/null
+++ b/git-revert.sh
@@ -0,0 +1,166 @@
+#!/bin/sh
+#
+# Copyright (c) 2005 Linus Torvalds
+# Copyright (c) 2005 Junio C Hamano
+#
+. git-sh-setup || die "Not a git archive"
+
+case "$0" in
+*-revert* )
+	me=revert ;;
+*-cherry-pick* )
+	me=cherry-pick ;;
+* )
+	die "What are ou talking about?" ;;
+esac
+
+usage () {
+	case "$me" in
+	cherry-pick)
+		die "usage git $me [-n] [-r] <commit-ish>"
+		;;
+	revert)
+		die "usage git $me [-n] <commit-ish>"
+		;;
+	esac
+}
+
+no_commit= replay=
+while case "$#" in 0) break ;; esac
+do
+	case "$1" in
+	-n|--n|--no|--no-|--no-c|--no-co|--no-com|--no-comm|\
+	    --no-commi|--no-commit)
+		no_commit=t
+		;;
+	-r|--r|--re|--rep|--repl|--repla|--replay)
+		replay=t
+		;;
+	-*)
+		usage
+		;;
+	*)
+		break
+		;;
+	esac
+	shift
+done
+
+test "$me,$replay" = "revert,t" && usage
+
+case "$no_commit" in
+t)
+	# We do not intend to commit immediately.  We just want to
+	# merge the differences in.
+	head=$(git-write-tree) ||
+		die "Your index file is unmerged."
+	;;
+*)
+	check_clean_tree || die "Cannot run $me from a dirty tree."
+	head=$(git-rev-parse --verify HEAD) ||
+		die "You do not have a valid HEAD"
+	;;
+esac
+
+rev=$(git-rev-parse --verify "$@") &&
+commit=$(git-rev-parse --verify "$rev^0") ||
+	die "Not a single commit $@"
+prev=$(git-rev-parse --verify "$commit^1" 2>/dev/null) ||
+	die "Cannot run $me a root commit"
+git-rev-parse --verify "$commit^2" >/dev/null 2>&1 &&
+	die "Cannot run $me a multi-parent commit."
+
+# "commit" is an existing commit.  We would want to apply
+# the difference it introduces since its first parent "prev"
+# on top of the current HEAD if we are cherry-pick.  Or the
+# reverse of it if we are revert.
+
+case "$me" in
+revert)
+	git-rev-list --pretty=oneline --max-count=1 $commit |
+	sed -e '
+		s/^[^ ]* /Revert "/
+		s/$/"/'
+	echo
+	echo "This reverts $commit commit."
+	test "$rev" = "$commit" ||
+	echo "(original 'git revert' arguments: $@)"
+	base=$commit next=$prev
+	;;
+
+cherry-pick)
+	pick_author_script='
+	/^author /{
+		h
+		s/^author \([^<]*\) <[^>]*> .*$/\1/
+		s/'\''/'\''\'\'\''/g
+		s/.*/GIT_AUTHOR_NAME='\''&'\''/p
+
+		g
+		s/^author [^<]* <\([^>]*\)> .*$/\1/
+		s/'\''/'\''\'\'\''/g
+		s/.*/GIT_AUTHOR_EMAIL='\''&'\''/p
+
+		g
+		s/^author [^<]* <[^>]*> \(.*\)$/\1/
+		s/'\''/'\''\'\'\''/g
+		s/.*/GIT_AUTHOR_DATE='\''&'\''/p
+
+		q
+	}'
+	set_author_env=`git-cat-file commit "$commit" |
+	sed -ne "$pick_author_script"`
+	eval "$set_author_env"
+	export GIT_AUTHOR_NAME
+	export GIT_AUTHOR_EMAIL
+	export GIT_AUTHOR_DATE
+
+	git-cat-file commit $commit | sed -e '1,/^$/d'
+	case "$replay" in
+	'')
+		echo "(cherry picked from $commit commit)"
+		test "$rev" = "$commit" ||
+		echo "(original 'git cherry-pick' arguments: $@)"
+		;;
+	esac
+	base=$prev next=$commit
+	;;
+
+esac >.msg
+
+# This three way merge is an interesting one.  We are at
+# $head, and would want to apply the change between $commit
+# and $prev on top of us (when reverting), or the change between
+# $prev and $commit on top of us (when cherry-picking or replaying).
+
+echo >&2 "First trying simple merge strategy to $me."
+git-read-tree -m -u $base $head $next &&
+result=$(git-write-tree 2>/dev/null) || {
+    echo >&2 "Simple $me fails; trying Automatic $me."
+    git-merge-index -o git-merge-one-file -a || {
+	    echo >&2 "Automatic $me failed.  After fixing it up,"
+	    echo >&2 "you can use \"git commit -F .msg\""
+	    case "$me" in
+	    cherry-pick)
+		echo >&2 "You may choose to use the following when making"
+		echo >&2 "the commit:"
+		echo >&2 "$set_author_env"
+	    esac
+	    exit 1
+    }
+    result=$(git-write-tree) || exit
+}
+echo >&2 "Finished one $me."
+
+# If we are cherry-pick, and if the merge did not result in
+# hand-editing, we will hit this commit and inherit the original
+# author date and name.
+# If we are revert, or if our cherry-pick results in a hand merge,
+# we had better say that the current user is responsible for that.
+
+case "$no_commit" in
+'')
+	git-commit -n -F .msg
+	rm -f .msg
+	;;
+esac