diff --git a/.gitignore b/.gitignore
index 32765a6ccb..7374587f9d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -162,7 +162,6 @@
 /git-show-ref
 /git-stage
 /git-stash
-/git-stash--helper
 /git-status
 /git-stripspace
 /git-submodule
diff --git a/Makefile b/Makefile
index 5c4b6e6ae5..c5240942f2 100644
--- a/Makefile
+++ b/Makefile
@@ -1138,7 +1138,6 @@ BUILTIN_OBJS += builtin/shortlog.o
 BUILTIN_OBJS += builtin/show-branch.o
 BUILTIN_OBJS += builtin/show-index.o
 BUILTIN_OBJS += builtin/show-ref.o
-BUILTIN_OBJS += builtin/stash--helper.o
 BUILTIN_OBJS += builtin/stripspace.o
 BUILTIN_OBJS += builtin/submodule--helper.o
 BUILTIN_OBJS += builtin/symbolic-ref.o
diff --git a/builtin.h b/builtin.h
index ff4460aff7..6538932e99 100644
--- a/builtin.h
+++ b/builtin.h
@@ -225,7 +225,6 @@ extern int cmd_show(int argc, const char **argv, const char *prefix);
 extern int cmd_show_branch(int argc, const char **argv, const char *prefix);
 extern int cmd_show_index(int argc, const char **argv, const char *prefix);
 extern int cmd_status(int argc, const char **argv, const char *prefix);
-extern int cmd_stash__helper(int argc, const char **argv, const char *prefix);
 extern int cmd_stripspace(int argc, const char **argv, const char *prefix);
 extern int cmd_submodule__helper(int argc, const char **argv, const char *prefix);
 extern int cmd_symbolic_ref(int argc, const char **argv, const char *prefix);
diff --git a/builtin/stash--helper.c b/builtin/stash--helper.c
deleted file mode 100644
index a9d55b1598..0000000000
--- a/builtin/stash--helper.c
+++ /dev/null
@@ -1,453 +0,0 @@
-#define USE_THE_INDEX_COMPATIBILITY_MACROS
-#include "builtin.h"
-#include "config.h"
-#include "parse-options.h"
-#include "refs.h"
-#include "lockfile.h"
-#include "cache-tree.h"
-#include "unpack-trees.h"
-#include "merge-recursive.h"
-#include "argv-array.h"
-#include "run-command.h"
-#include "dir.h"
-#include "rerere.h"
-
-static const char * const git_stash_helper_usage[] = {
-	N_("git stash--helper apply [--index] [-q|--quiet] [<stash>]"),
-	NULL
-};
-
-static const char * const git_stash_helper_apply_usage[] = {
-	N_("git stash--helper apply [--index] [-q|--quiet] [<stash>]"),
-	NULL
-};
-
-static const char *ref_stash = "refs/stash";
-static struct strbuf stash_index_path = STRBUF_INIT;
-
-/*
- * 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
- * u_commit is set to the commit containing the untracked files 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
- * u_tree is set to the untracked files tree
- */
-
-struct stash_info {
-	struct object_id w_commit;
-	struct object_id b_commit;
-	struct object_id i_commit;
-	struct object_id u_commit;
-	struct object_id w_tree;
-	struct object_id b_tree;
-	struct object_id i_tree;
-	struct object_id u_tree;
-	struct strbuf revision;
-	int is_stash_ref;
-	int has_u;
-};
-
-static void free_stash_info(struct stash_info *info)
-{
-	strbuf_release(&info->revision);
-}
-
-static void assert_stash_like(struct stash_info *info, const char *revision)
-{
-	if (get_oidf(&info->b_commit, "%s^1", revision) ||
-	    get_oidf(&info->w_tree, "%s:", revision) ||
-	    get_oidf(&info->b_tree, "%s^1:", revision) ||
-	    get_oidf(&info->i_tree, "%s^2:", revision))
-		die(_("'%s' is not a stash-like commit"), revision);
-}
-
-static int get_stash_info(struct stash_info *info, int argc, const char **argv)
-{
-	int ret;
-	char *end_of_rev;
-	char *expanded_ref;
-	const char *revision;
-	const char *commit = NULL;
-	struct object_id dummy;
-	struct strbuf symbolic = STRBUF_INIT;
-
-	if (argc > 1) {
-		int i;
-		struct strbuf refs_msg = STRBUF_INIT;
-
-		for (i = 0; i < argc; i++)
-			strbuf_addf(&refs_msg, " '%s'", argv[i]);
-
-		fprintf_ln(stderr, _("Too many revisions specified:%s"),
-			   refs_msg.buf);
-		strbuf_release(&refs_msg);
-
-		return -1;
-	}
-
-	if (argc == 1)
-		commit = argv[0];
-
-	strbuf_init(&info->revision, 0);
-	if (!commit) {
-		if (!ref_exists(ref_stash)) {
-			free_stash_info(info);
-			fprintf_ln(stderr, _("No stash entries found."));
-			return -1;
-		}
-
-		strbuf_addf(&info->revision, "%s@{0}", ref_stash);
-	} else if (strspn(commit, "0123456789") == strlen(commit)) {
-		strbuf_addf(&info->revision, "%s@{%s}", ref_stash, commit);
-	} else {
-		strbuf_addstr(&info->revision, commit);
-	}
-
-	revision = info->revision.buf;
-
-	if (get_oid(revision, &info->w_commit)) {
-		error(_("%s is not a valid reference"), revision);
-		free_stash_info(info);
-		return -1;
-	}
-
-	assert_stash_like(info, revision);
-
-	info->has_u = !get_oidf(&info->u_tree, "%s^3:", revision);
-
-	end_of_rev = strchrnul(revision, '@');
-	strbuf_add(&symbolic, revision, end_of_rev - revision);
-
-	ret = dwim_ref(symbolic.buf, symbolic.len, &dummy, &expanded_ref);
-	strbuf_release(&symbolic);
-	switch (ret) {
-	case 0: /* Not found, but valid ref */
-		info->is_stash_ref = 0;
-		break;
-	case 1:
-		info->is_stash_ref = !strcmp(expanded_ref, ref_stash);
-		break;
-	default: /* Invalid or ambiguous */
-		free_stash_info(info);
-	}
-
-	free(expanded_ref);
-	return !(ret == 0 || ret == 1);
-}
-
-static int reset_tree(struct object_id *i_tree, int update, int reset)
-{
-	int nr_trees = 1;
-	struct unpack_trees_options opts;
-	struct tree_desc t[MAX_UNPACK_TREES];
-	struct tree *tree;
-	struct lock_file lock_file = LOCK_INIT;
-
-	read_cache_preload(NULL);
-	if (refresh_cache(REFRESH_QUIET))
-		return -1;
-
-	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
-
-	memset(&opts, 0, sizeof(opts));
-
-	tree = parse_tree_indirect(i_tree);
-	if (parse_tree(tree))
-		return -1;
-
-	init_tree_desc(t, tree->buffer, tree->size);
-
-	opts.head_idx = 1;
-	opts.src_index = &the_index;
-	opts.dst_index = &the_index;
-	opts.merge = 1;
-	opts.reset = reset;
-	opts.update = update;
-	opts.fn = oneway_merge;
-
-	if (unpack_trees(nr_trees, t, &opts))
-		return -1;
-
-	if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
-		return error(_("unable to write new index file"));
-
-	return 0;
-}
-
-static int diff_tree_binary(struct strbuf *out, struct object_id *w_commit)
-{
-	struct child_process cp = CHILD_PROCESS_INIT;
-	const char *w_commit_hex = oid_to_hex(w_commit);
-
-	/*
-	 * Diff-tree would not be very hard to replace with a native function,
-	 * however it should be done together with apply_cached.
-	 */
-	cp.git_cmd = 1;
-	argv_array_pushl(&cp.args, "diff-tree", "--binary", NULL);
-	argv_array_pushf(&cp.args, "%s^2^..%s^2", w_commit_hex, w_commit_hex);
-
-	return pipe_command(&cp, NULL, 0, out, 0, NULL, 0);
-}
-
-static int apply_cached(struct strbuf *out)
-{
-	struct child_process cp = CHILD_PROCESS_INIT;
-
-	/*
-	 * Apply currently only reads either from stdin or a file, thus
-	 * apply_all_patches would have to be updated to optionally take a
-	 * buffer.
-	 */
-	cp.git_cmd = 1;
-	argv_array_pushl(&cp.args, "apply", "--cached", NULL);
-	return pipe_command(&cp, out->buf, out->len, NULL, 0, NULL, 0);
-}
-
-static int reset_head(void)
-{
-	struct child_process cp = CHILD_PROCESS_INIT;
-
-	/*
-	 * Reset is overall quite simple, however there is no current public
-	 * API for resetting.
-	 */
-	cp.git_cmd = 1;
-	argv_array_push(&cp.args, "reset");
-
-	return run_command(&cp);
-}
-
-static int get_newly_staged(struct strbuf *out, struct object_id *c_tree)
-{
-	struct child_process cp = CHILD_PROCESS_INIT;
-	const char *c_tree_hex = oid_to_hex(c_tree);
-
-	/*
-	 * diff-index is very similar to diff-tree above, and should be
-	 * converted together with update_index.
-	 */
-	cp.git_cmd = 1;
-	argv_array_pushl(&cp.args, "diff-index", "--cached", "--name-only",
-			 "--diff-filter=A", NULL);
-	argv_array_push(&cp.args, c_tree_hex);
-	return pipe_command(&cp, NULL, 0, out, 0, NULL, 0);
-}
-
-static int update_index(struct strbuf *out)
-{
-	struct child_process cp = CHILD_PROCESS_INIT;
-
-	/*
-	 * Update-index is very complicated and may need to have a public
-	 * function exposed in order to remove this forking.
-	 */
-	cp.git_cmd = 1;
-	argv_array_pushl(&cp.args, "update-index", "--add", "--stdin", NULL);
-	return pipe_command(&cp, out->buf, out->len, NULL, 0, NULL, 0);
-}
-
-static int restore_untracked(struct object_id *u_tree)
-{
-	int res;
-	struct child_process cp = CHILD_PROCESS_INIT;
-
-	/*
-	 * We need to run restore files from a given index, but without
-	 * affecting the current index, so we use GIT_INDEX_FILE with
-	 * run_command to fork processes that will not interfere.
-	 */
-	cp.git_cmd = 1;
-	argv_array_push(&cp.args, "read-tree");
-	argv_array_push(&cp.args, oid_to_hex(u_tree));
-	argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s",
-			 stash_index_path.buf);
-	if (run_command(&cp)) {
-		remove_path(stash_index_path.buf);
-		return -1;
-	}
-
-	child_process_init(&cp);
-	cp.git_cmd = 1;
-	argv_array_pushl(&cp.args, "checkout-index", "--all", NULL);
-	argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s",
-			 stash_index_path.buf);
-
-	res = run_command(&cp);
-	remove_path(stash_index_path.buf);
-	return res;
-}
-
-static int do_apply_stash(const char *prefix, struct stash_info *info,
-			  int index, int quiet)
-{
-	int ret;
-	int has_index = index;
-	struct merge_options o;
-	struct object_id c_tree;
-	struct object_id index_tree;
-	struct commit *result;
-	const struct object_id *bases[1];
-
-	read_cache_preload(NULL);
-	if (refresh_cache(REFRESH_QUIET))
-		return -1;
-
-	if (write_cache_as_tree(&c_tree, 0, NULL) || reset_tree(&c_tree, 0, 0))
-		return error(_("cannot apply a stash in the middle of a merge"));
-
-	if (index) {
-		if (oideq(&info->b_tree, &info->i_tree) ||
-		    oideq(&c_tree, &info->i_tree)) {
-			has_index = 0;
-		} else {
-			struct strbuf out = STRBUF_INIT;
-
-			if (diff_tree_binary(&out, &info->w_commit)) {
-				strbuf_release(&out);
-				return error(_("could not generate diff %s^!."),
-					     oid_to_hex(&info->w_commit));
-			}
-
-			ret = apply_cached(&out);
-			strbuf_release(&out);
-			if (ret)
-				return error(_("conflicts in index."
-					       "Try without --index."));
-
-			discard_cache();
-			read_cache();
-			if (write_cache_as_tree(&index_tree, 0, NULL))
-				return error(_("could not save index tree"));
-
-			reset_head();
-		}
-	}
-
-	if (info->has_u && restore_untracked(&info->u_tree))
-		return error(_("could not restore untracked files from stash"));
-
-	init_merge_options(&o, the_repository);
-
-	o.branch1 = "Updated upstream";
-	o.branch2 = "Stashed changes";
-
-	if (oideq(&info->b_tree, &c_tree))
-		o.branch1 = "Version stash was based on";
-
-	if (quiet)
-		o.verbosity = 0;
-
-	if (o.verbosity >= 3)
-		printf_ln(_("Merging %s with %s"), o.branch1, o.branch2);
-
-	bases[0] = &info->b_tree;
-
-	ret = merge_recursive_generic(&o, &c_tree, &info->w_tree, 1, bases,
-				      &result);
-	if (ret) {
-		rerere(0);
-
-		if (index)
-			fprintf_ln(stderr, _("Index was not unstashed."));
-
-		return ret;
-	}
-
-	if (has_index) {
-		if (reset_tree(&index_tree, 0, 0))
-			return -1;
-	} else {
-		struct strbuf out = STRBUF_INIT;
-
-		if (get_newly_staged(&out, &c_tree)) {
-			strbuf_release(&out);
-			return -1;
-		}
-
-		if (reset_tree(&c_tree, 0, 1)) {
-			strbuf_release(&out);
-			return -1;
-		}
-
-		ret = update_index(&out);
-		strbuf_release(&out);
-		if (ret)
-			return -1;
-
-		discard_cache();
-	}
-
-	if (quiet) {
-		if (refresh_cache(REFRESH_QUIET))
-			warning("could not refresh index");
-	} else {
-		struct child_process cp = CHILD_PROCESS_INIT;
-
-		/*
-		 * Status is quite simple and could be replaced with calls to
-		 * wt_status in the future, but it adds complexities which may
-		 * require more tests.
-		 */
-		cp.git_cmd = 1;
-		cp.dir = prefix;
-		argv_array_push(&cp.args, "status");
-		run_command(&cp);
-	}
-
-	return 0;
-}
-
-static int apply_stash(int argc, const char **argv, const char *prefix)
-{
-	int ret;
-	int quiet = 0;
-	int index = 0;
-	struct stash_info info;
-	struct option options[] = {
-		OPT__QUIET(&quiet, N_("be quiet, only report errors")),
-		OPT_BOOL(0, "index", &index,
-			 N_("attempt to recreate the index")),
-		OPT_END()
-	};
-
-	argc = parse_options(argc, argv, prefix, options,
-			     git_stash_helper_apply_usage, 0);
-
-	if (get_stash_info(&info, argc, argv))
-		return -1;
-
-	ret = do_apply_stash(prefix, &info, index, quiet);
-	free_stash_info(&info);
-	return ret;
-}
-
-int cmd_stash__helper(int argc, const char **argv, const char *prefix)
-{
-	pid_t pid = getpid();
-	const char *index_file;
-
-	struct option options[] = {
-		OPT_END()
-	};
-
-	git_config(git_default_config, NULL);
-
-	argc = parse_options(argc, argv, prefix, options, git_stash_helper_usage,
-			     PARSE_OPT_KEEP_UNKNOWN | PARSE_OPT_KEEP_DASHDASH);
-
-	index_file = get_index_file();
-	strbuf_addf(&stash_index_path, "%s.stash.%" PRIuMAX, index_file,
-		    (uintmax_t)pid);
-
-	if (argc < 1)
-		usage_with_options(git_stash_helper_usage, options);
-	if (!strcmp(argv[0], "apply"))
-		return !!apply_stash(argc, argv, prefix);
-
-	usage_msg_opt(xstrfmt(_("unknown subcommand: %s"), argv[0]),
-		      git_stash_helper_usage, options);
-}
diff --git a/git-stash.sh b/git-stash.sh
index 366a082853..789ce2f41d 100755
--- a/git-stash.sh
+++ b/git-stash.sh
@@ -583,11 +583,76 @@ assert_stash_ref() {
 }
 
 apply_stash () {
-	cd "$START_DIR"
-	git stash--helper apply "$@"
-	res=$?
-	cd_to_toplevel
-	return $res
+
+	assert_stash_like "$@"
+
+	git update-index -q --refresh || die "$(gettext "unable to refresh index")"
+
+	# current index state
+	c_tree=$(git write-tree) ||
+		die "$(gettext "Cannot apply a stash in the middle of a merge")"
+
+	unstashed_index_tree=
+	if test -n "$INDEX_OPTION" && test "$b_tree" != "$i_tree" &&
+			test "$c_tree" != "$i_tree"
+	then
+		git diff-tree --binary $s^2^..$s^2 | git apply --cached
+		test $? -ne 0 &&
+			die "$(gettext "Conflicts in index. Try without --index.")"
+		unstashed_index_tree=$(git write-tree) ||
+			die "$(gettext "Could not save index tree")"
+		git reset
+	fi
+
+	if test -n "$u_tree"
+	then
+		GIT_INDEX_FILE="$TMPindex" git read-tree "$u_tree" &&
+		GIT_INDEX_FILE="$TMPindex" git checkout-index --all &&
+		rm -f "$TMPindex" ||
+		die "$(gettext "Could not restore untracked files from stash entry")"
+	fi
+
+	eval "
+		GITHEAD_$w_tree='Stashed changes' &&
+		GITHEAD_$c_tree='Updated upstream' &&
+		GITHEAD_$b_tree='Version stash was based on' &&
+		export GITHEAD_$w_tree GITHEAD_$c_tree GITHEAD_$b_tree
+	"
+
+	if test -n "$GIT_QUIET"
+	then
+		GIT_MERGE_VERBOSITY=0 && export GIT_MERGE_VERBOSITY
+	fi
+	if git merge-recursive $b_tree -- $c_tree $w_tree
+	then
+		# No conflict
+		if test -n "$unstashed_index_tree"
+		then
+			git read-tree "$unstashed_index_tree"
+		else
+			a="$TMP-added" &&
+			git diff-index --cached --name-only --diff-filter=A $c_tree >"$a" &&
+			git read-tree --reset $c_tree &&
+			git update-index --add --stdin <"$a" ||
+				die "$(gettext "Cannot unstage modified files")"
+			rm -f "$a"
+		fi
+		squelch=
+		if test -n "$GIT_QUIET"
+		then
+			squelch='>/dev/null 2>&1'
+		fi
+		(cd "$START_DIR" && eval "git status $squelch") || :
+	else
+		# Merge conflict; keep the exit status from merge-recursive
+		status=$?
+		git rerere
+		if test -n "$INDEX_OPTION"
+		then
+			gettextln "Index was not unstashed." >&2
+		fi
+		exit $status
+	fi
 }
 
 pop_stash() {
@@ -665,8 +730,7 @@ push)
 	;;
 apply)
 	shift
-	cd "$START_DIR"
-	git stash--helper apply "$@"
+	apply_stash "$@"
 	;;
 clear)
 	shift
diff --git a/git.c b/git.c
index c041c6e057..2dd588674f 100644
--- a/git.c
+++ b/git.c
@@ -555,7 +555,6 @@ static struct cmd_struct commands[] = {
 	{ "show-index", cmd_show_index },
 	{ "show-ref", cmd_show_ref, RUN_SETUP },
 	{ "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
-	{ "stash--helper", cmd_stash__helper, RUN_SETUP | NEED_WORK_TREE },
 	{ "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 	{ "stripspace", cmd_stripspace },
 	{ "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT },