subtree: be stricter about validating flags

Don't silently ignore a flag that's invalid for a given subcommand.  The
user expected it to do something; we should tell the user that they are
mistaken, instead of surprising the user.

It could be argued that this change might break existing users.  I'd
argue that those existing users are already broken, and they just don't
know it.  Let them know that they're broken.

Signed-off-by: Luke Shumaker <lukeshu@datawire.io>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 64 insertions, 25 deletions

diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index 9e4d9a0619..b06782bc79 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -44,17 +44,6 @@ squash        merge subtree changes as a single commit
 m,message=    use the given message as the commit message for the merge commit
 "
 
-arg_debug=
-arg_command=
-arg_prefix=
-arg_split_branch=
-arg_split_onto=
-arg_split_rejoin=
-arg_split_ignore_joins=
-arg_split_annotate=
-arg_addmerge_squash=
-arg_addmerge_message=
-
 indent=0
 
 # Usage: debug [MSG...]
@@ -106,10 +95,61 @@ main () {
 	then
 		set -- -h
 	fi
-	eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
+	set_args="$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
+	eval "$set_args"
 	. git-sh-setup
 	require_work_tree
 
+	# First figure out the command and whether we use --rejoin, so
+	# that we can provide more helpful validation when we do the
+	# "real" flag parsing.
+	arg_split_rejoin=
+	allow_split=
+	allow_addmerge=
+	while test $# -gt 0
+	do
+		opt="$1"
+		shift
+		case "$opt" in
+			--annotate|-b|-P|-m|--onto)
+				shift
+				;;
+			--rejoin)
+				arg_split_rejoin=1
+				;;
+			--no-rejoin)
+				arg_split_rejoin=
+				;;
+			--)
+				break
+				;;
+		esac
+	done
+	arg_command=$1
+	case "$arg_command" in
+	add|merge|pull)
+		allow_addmerge=1
+		;;
+	split|push)
+		allow_split=1
+		allow_addmerge=$arg_split_rejoin
+		;;
+	*)
+		die "Unknown command '$arg_command'"
+		;;
+	esac
+	# Reset the arguments array for "real" flag parsing.
+	eval "$set_args"
+
+	# Begin "real" flag parsing.
+	arg_debug=
+	arg_prefix=
+	arg_split_branch=
+	arg_split_onto=
+	arg_split_ignore_joins=
+	arg_split_annotate=
+	arg_addmerge_squash=
+	arg_addmerge_message=
 	while test $# -gt 0
 	do
 		opt="$1"
@@ -123,13 +163,16 @@ main () {
 			arg_debug=1
 			;;
 		--annotate)
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_split_annotate="$1"
 			shift
 			;;
 		--no-annotate)
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_split_annotate=
 			;;
 		-b)
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_split_branch="$1"
 			shift
 			;;
@@ -138,6 +181,7 @@ main () {
 			shift
 			;;
 		-m)
+			test -n "$allow_addmerge" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_addmerge_message="$1"
 			shift
 			;;
@@ -145,28 +189,34 @@ main () {
 			arg_prefix=
 			;;
 		--onto)
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_split_onto="$1"
 			shift
 			;;
 		--no-onto)
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_split_onto=
 			;;
 		--rejoin)
-			arg_split_rejoin=1
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			;;
 		--no-rejoin)
-			arg_split_rejoin=
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			;;
 		--ignore-joins)
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_split_ignore_joins=1
 			;;
 		--no-ignore-joins)
+			test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_split_ignore_joins=
 			;;
 		--squash)
+			test -n "$allow_addmerge" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_addmerge_squash=1
 			;;
 		--no-squash)
+			test -n "$allow_addmerge" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
 			arg_addmerge_squash=
 			;;
 		--)
@@ -177,19 +227,8 @@ main () {
 			;;
 		esac
 	done
-
-	arg_command="$1"
 	shift
 
-	case "$arg_command" in
-	add|merge|pull|split|push)
-		:
-		;;
-	*)
-		die "Unknown command '$arg_command'"
-		;;
-	esac
-
 	if test -z "$arg_prefix"
 	then
 		die "You must provide the --prefix option."