1 files changed, 141 insertions, 81 deletions
diff --git a/git-stash.sh b/git-stash.sh
index 1d95447d03..7561b374d2 100755
--- a/git-stash.sh
+++ b/git-stash.sh
@@ -210,56 +210,139 @@ list_stash () {
 }
 
 show_stash () {
-	have_stash || die 'No stash found'
+	assert_stash_like "$@"
 
-	flags=$(git rev-parse --no-revs --flags "$@")
-	if test -z "$flags"
-	then
-		flags=--stat
-	fi
-
-	w_commit=$(git rev-parse --quiet --verify --default $ref_stash "$@") &&
-	b_commit=$(git rev-parse --quiet --verify "$w_commit^") ||
-		die "'$*' is not a stash"
-
-	git diff $flags $b_commit $w_commit
+	git diff ${FLAGS:---stat} $b_commit $w_commit
 }
 
-apply_stash () {
-	applied_stash=
-	unstash_index=
-
-	while test $# != 0
+#
+# Parses the remaining options looking for flags and
+# at most one revision defaulting to ${ref_stash}@{0}
+# if none found.
+#
+# Derives related tree and commit objects from the
+# revision, if one is found.
+#
+# stash records the work tree, and is a merge between the
+# base commit (first parent) and the index tree (second parent).
+#
+#   REV is set to the symbolic version of the specified stash-like commit
+#   IS_STASH_LIKE is non-blank if ${REV} looks like a stash
+#   IS_STASH_REF is non-blank if the ${REV} looks like a stash ref
+#   s is set to the SHA1 of the stash commit
+#   w_commit is set to the commit containing the working tree
+#   b_commit is set to the base commit
+#   i_commit is set to the commit containing the index tree
+#   w_tree is set to the working tree
+#   b_tree is set to the base tree
+#   i_tree is set to the index tree
+#
+#   GIT_QUIET is set to t if -q is specified
+#   INDEX_OPTION is set to --index if --index is specified.
+#   FLAGS is set to the remaining flags
+#
+# dies if:
+#   * too many revisions specified
+#   * no revision is specified and there is no stash stack
+#   * a revision is specified which cannot be resolve to a SHA1
+#   * a non-existent stash reference is specified
+#
+
+parse_flags_and_rev()
+{
+	test "$PARSE_CACHE" = "$*" && return 0 # optimisation
+	PARSE_CACHE="$*"
+
+	IS_STASH_LIKE=
+	IS_STASH_REF=
+	INDEX_OPTION=
+	s=
+	w_commit=
+	b_commit=
+	i_commit=
+	w_tree=
+	b_tree=
+	i_tree=
+
+	REV=$(git rev-parse --no-flags --symbolic "$@" 2>/dev/null)
+
+	FLAGS=
+	for opt
 	do
-		case "$1" in
-		--index)
-			unstash_index=t
+		case "$opt" in
+			-q|--quiet)
+				GIT_QUIET=-t
 			;;
-		-q|--quiet)
-			GIT_QUIET=t
+			--index)
+				INDEX_OPTION=--index
 			;;
-		*)
-			break
+			-*)
+				FLAGS="${FLAGS}${FLAGS:+ }$opt"
 			;;
 		esac
-		shift
 	done
 
-	if test $# = 0
+	set -- $REV
+
+	case $# in
+		0)
+			have_stash || die "No stash found."
+			set -- ${ref_stash}@{0}
+		;;
+		1)
+			:
+		;;
+		*)
+			die "Too many revisions specified: $REV"
+		;;
+	esac
+
+	REV=$(git rev-parse --quiet --symbolic --verify $1 2>/dev/null) || die "$1 is not valid reference"
+
+	i_commit=$(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) &&
+	s=$1 &&
+	w_commit=$1 &&
+	b_commit=$2 &&
+	w_tree=$3 &&
+	b_tree=$4 &&
+	i_tree=$5 &&
+	IS_STASH_LIKE=t &&
+	test "$ref_stash" = "$(git rev-parse --symbolic-full-name "${REV%@*}")" &&
+	IS_STASH_REF=t
+
+	if test "${REV}" != "${REV%{*\}}"
 	then
-		have_stash || die 'Nothing to apply'
-		applied_stash="$ref_stash@{0}"
-	else
-		applied_stash="$*"
+		# maintainers: it would be better if git rev-parse indicated
+		# this condition with a non-zero status code but as of 1.7.2.1 it
+		# it did not. So, we use non-empty stderr output as a proxy for the
+		# condition of interest.
+		test -z "$(git rev-parse "$REV" 2>&1 >/dev/null)" || die "$REV does not exist in the stash log"
 	fi
 
-	# stash records the work tree, and is a merge between the
-	# base commit (first parent) and the index tree (second parent).
-	s=$(git rev-parse --quiet --verify --default $ref_stash "$@") &&
-	w_tree=$(git rev-parse --quiet --verify "$s:") &&
-	b_tree=$(git rev-parse --quiet --verify "$s^1:") &&
-	i_tree=$(git rev-parse --quiet --verify "$s^2:") ||
-		die "$*: no valid stashed state found"
+}
+
+is_stash_like()
+{
+	parse_flags_and_rev "$@"
+	test -n "$IS_STASH_LIKE"
+}
+
+assert_stash_like() {
+	is_stash_like "$@" || die "'$*' is not a stash-like commit"
+}
+
+is_stash_ref() {
+	is_stash_like "$@" && test -n "$IS_STASH_REF"
+}
+
+assert_stash_ref() {
+	is_stash_ref "$@" || die "'$*' is not a stash reference"
+}
+
+apply_stash () {
+
+	assert_stash_like "$@"
 
 	git update-index -q --refresh &&
 	git diff-files --quiet --ignore-submodules ||
@@ -270,7 +353,7 @@ apply_stash () {
 		die 'Cannot apply a stash in the middle of a merge'
 
 	unstashed_index_tree=
-	if test -n "$unstash_index" && test "$b_tree" != "$i_tree" &&
+	if test -n "$INDEX_OPTION" && test "$b_tree" != "$i_tree" &&
 			test "$c_tree" != "$i_tree"
 	then
 		git diff-tree --binary $s^2^..$s^2 | git apply --cached
@@ -290,7 +373,7 @@ apply_stash () {
 
 	if test -n "$GIT_QUIET"
 	then
-		export GIT_MERGE_VERBOSITY=0
+		GIT_MERGE_VERBOSITY=0 && export GIT_MERGE_VERBOSITY
 	fi
 	if git merge-recursive $b_tree -- $c_tree $w_tree
 	then
@@ -315,7 +398,7 @@ apply_stash () {
 	else
 		# Merge conflict; keep the exit status from merge-recursive
 		status=$?
-		if test -n "$unstash_index"
+		if test -n "$INDEX_OPTION"
 		then
 			echo >&2 'Index was not unstashed.'
 		fi
@@ -323,58 +406,38 @@ apply_stash () {
 	fi
 }
 
-drop_stash () {
-	have_stash || die 'No stash entries to drop'
+pop_stash() {
+	assert_stash_ref "$@"
 
-	while test $# != 0
-	do
-		case "$1" in
-		-q|--quiet)
-			GIT_QUIET=t
-			;;
-		*)
-			break
-			;;
-		esac
-		shift
-	done
+	apply_stash "$@" &&
+	drop_stash "$@"
+}
 
-	if test $# = 0
-	then
-		set x "$ref_stash@{0}"
-		shift
-	fi
-	# Verify supplied argument looks like a stash entry
-	s=$(git rev-parse --verify "$@") &&
-	git rev-parse --verify "$s:"   > /dev/null 2>&1 &&
-	git rev-parse --verify "$s^1:" > /dev/null 2>&1 &&
-	git rev-parse --verify "$s^2:" > /dev/null 2>&1 ||
-		die "$*: not a valid stashed state"
+drop_stash () {
+	assert_stash_ref "$@"
 
-	git reflog delete --updateref --rewrite "$@" &&
-		say "Dropped $* ($s)" || die "$*: Could not drop stash entry"
+	git reflog delete --updateref --rewrite "${REV}" &&
+		say "Dropped ${REV} ($s)" || die "${REV}: Could not drop stash entry"
 
 	# clear_stash if we just dropped the last stash entry
 	git rev-parse --verify "$ref_stash@{0}" > /dev/null 2>&1 || clear_stash
 }
 
 apply_to_branch () {
-	have_stash || die 'Nothing to apply'
-
 	test -n "$1" || die 'No branch name specified'
 	branch=$1
+	shift 1
 
-	if test -z "$2"
-	then
-		set x "$ref_stash@{0}"
-	fi
-	stash=$2
+	set -- --index "$@"
+	assert_stash_like "$@"
 
-	git checkout -b $branch $stash^ &&
-	apply_stash --index $stash &&
-	drop_stash $stash
+	git checkout -b $branch $REV^ &&
+	apply_stash "$@" && {
+		test -z "$IS_STASH_REF" || drop_stash "$@"
+	}
 }
 
+PARSE_CACHE='--not-parsed'
 # The default command is "save" if nothing but options are given
 seen_non_option=
 for opt
@@ -422,10 +485,7 @@ drop)
 	;;
 pop)
 	shift
-	if apply_stash "$@"
-	then
-		drop_stash "$applied_stash"
-	fi
+	pop_stash "$@"
 	;;
 branch)
 	shift