stash: handle specifying stashes with $IFS

When trying to pop/apply a stash specified with an argument
containing IFS whitespace, git-stash will throw an error:

    $ git stash pop 'stash@{two hours ago}'
    Too many revisions specified: stash@{two hours ago}

This happens because word splitting is used to count non-option
arguments. Make use of rev-parse's --sq option to quote the arguments
for us to ensure a correct count. Add quotes where necessary.

Also add a test that verifies correct behaviour.
Helped-by: NThomas Rast <tr@thomasrast.ch>
Signed-off-by: NØystein Walle <oystwa@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-stash.sh

@@ -358,7 +358,7 @@ parse_flags_and_rev()
 	i_tree=
 	u_tree=
 
-	REV=$(git rev-parse --no-flags --symbolic "$@") || exit 1
+	REV=$(git rev-parse --no-flags --symbolic --sq "$@") || exit 1
 
 	FLAGS=
 	for opt
@@ -376,7 +376,7 @@ parse_flags_and_rev()
 		esac
 	done
 
-	set -- $REV
+	eval set -- $REV
 
 	case $# in
 		0)
@@ -391,13 +391,13 @@ parse_flags_and_rev()
 		;;
 	esac
 
-	REV=$(git rev-parse --quiet --symbolic --verify $1 2>/dev/null) || {
+	REV=$(git rev-parse --quiet --symbolic --verify "$1" 2>/dev/null) || {
 		reference="$1"
 		die "$(eval_gettext "\$reference is not valid reference")"
 	}
 
-	i_commit=$(git rev-parse --quiet --verify $REV^2 2>/dev/null) &&
-	set -- $(git rev-parse $REV $REV^1 $REV: $REV^1: $REV^2: 2>/dev/null) &&
+	i_commit=$(git rev-parse --quiet --verify "$REV^2" 2>/dev/null) &&
+	set -- $(git rev-parse "$REV" "$REV^1" "$REV:" "$REV^1:" "$REV^2:" 2>/dev/null) &&
 	s=$1 &&
 	w_commit=$1 &&
 	b_commit=$2 &&
@@ -408,8 +408,8 @@ parse_flags_and_rev()
 	test "$ref_stash" = "$(git rev-parse --symbolic-full-name "${REV%@*}")" &&
 	IS_STASH_REF=t
 
-	u_commit=$(git rev-parse --quiet --verify $REV^3 2>/dev/null) &&
-	u_tree=$(git rev-parse $REV^3: 2>/dev/null)
+	u_commit=$(git rev-parse --quiet --verify "$REV^3" 2>/dev/null) &&
+	u_tree=$(git rev-parse "$REV^3:" 2>/dev/null)
 }
 
 is_stash_like()

t/t3903-stash.sh

@@ -673,4 +673,16 @@ test_expect_success 'store updates stash ref and reflog' '
 	grep quux bazzy
 '
 
+test_expect_success 'handle stash specification with spaces' '
+	git stash clear &&
+	echo pig >file &&
+	git stash &&
+	stamp=$(git log -g --format="%cd" -1 refs/stash) &&
+	test_tick &&
+	echo cow >file &&
+	git stash &&
+	git stash apply "stash@{$stamp}" &&
+	grep pig file
+'
+
 test_done