From 6a9d54d671c911ffa8de840c6ef28f9ed1f391d8 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 24 Aug 2018 15:14:04 +0200
Subject: [PATCH 1/6] Add back the original, scripted interactive rebase
 backend

This simply copies the version as of v2.19.0-rc0 verbatim. As of now,
it is not hooked up (because it needs a couple more changes to work);
The next commit will use the scripted interactive rebase backend from
`git rebase` again when `rebase.useBuiltin=false`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 git-rebase--interactive.sh | 283 +++++++++++++++++++++++++++++++++++++
 1 file changed, 283 insertions(+)
 create mode 100644 git-rebase--interactive.sh

diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
new file mode 100644
index 0000000000..299ded2137
--- /dev/null
+++ b/git-rebase--interactive.sh
@@ -0,0 +1,283 @@
+# This shell script fragment is sourced by git-rebase to implement
+# its interactive mode.  "git rebase --interactive" makes it easy
+# to fix up commits in the middle of a series and rearrange commits.
+#
+# Copyright (c) 2006 Johannes E. Schindelin
+#
+# The original idea comes from Eric W. Biederman, in
+# https://public-inbox.org/git/m1odwkyuf5.fsf_-_@ebiederm.dsl.xmission.com/
+#
+# The file containing rebase commands, comments, and empty lines.
+# This file is created by "git rebase -i" then edited by the user.  As
+# the lines are processed, they are removed from the front of this
+# file and written to the tail of $done.
+todo="$state_dir"/git-rebase-todo
+
+GIT_CHERRY_PICK_HELP="$resolvemsg"
+export GIT_CHERRY_PICK_HELP
+
+comment_char=$(git config --get core.commentchar 2>/dev/null)
+case "$comment_char" in
+'' | auto)
+	comment_char="#"
+	;;
+?)
+	;;
+*)
+	comment_char=$(echo "$comment_char" | cut -c1)
+	;;
+esac
+
+orig_reflog_action="$GIT_REFLOG_ACTION"
+
+comment_for_reflog () {
+	case "$orig_reflog_action" in
+	''|rebase*)
+		GIT_REFLOG_ACTION="rebase -i ($1)"
+		export GIT_REFLOG_ACTION
+		;;
+	esac
+}
+
+append_todo_help () {
+	gettext "
+Commands:
+p, pick <commit> = use commit
+r, reword <commit> = use commit, but edit the commit message
+e, edit <commit> = use commit, but stop for amending
+s, squash <commit> = use commit, but meld into previous commit
+f, fixup <commit> = like \"squash\", but discard this commit's log message
+x, exec <command> = run command (the rest of the line) using shell
+d, drop <commit> = remove commit
+l, label <label> = label current HEAD with a name
+t, reset <label> = reset HEAD to a label
+m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]
+.       create a merge commit using the original merge commit's
+.       message (or the oneline, if no original merge commit was
+.       specified). Use -c <commit> to reword the commit message.
+
+These lines can be re-ordered; they are executed from top to bottom.
+" | git stripspace --comment-lines >>"$todo"
+
+	if test $(get_missing_commit_check_level) = error
+	then
+		gettext "
+Do not remove any line. Use 'drop' explicitly to remove a commit.
+" | git stripspace --comment-lines >>"$todo"
+	else
+		gettext "
+If you remove a line here THAT COMMIT WILL BE LOST.
+" | git stripspace --comment-lines >>"$todo"
+	fi
+}
+
+die_abort () {
+	apply_autostash
+	rm -rf "$state_dir"
+	die "$1"
+}
+
+has_action () {
+	test -n "$(git stripspace --strip-comments <"$1")"
+}
+
+git_sequence_editor () {
+	if test -z "$GIT_SEQUENCE_EDITOR"
+	then
+		GIT_SEQUENCE_EDITOR="$(git config sequence.editor)"
+		if [ -z "$GIT_SEQUENCE_EDITOR" ]
+		then
+			GIT_SEQUENCE_EDITOR="$(git var GIT_EDITOR)" || return $?
+		fi
+	fi
+
+	eval "$GIT_SEQUENCE_EDITOR" '"$@"'
+}
+
+expand_todo_ids() {
+	git rebase--helper --expand-ids
+}
+
+collapse_todo_ids() {
+	git rebase--helper --shorten-ids
+}
+
+# Switch to the branch in $into and notify it in the reflog
+checkout_onto () {
+	GIT_REFLOG_ACTION="$GIT_REFLOG_ACTION: checkout $onto_name"
+	output git checkout $onto || die_abort "$(gettext "could not detach HEAD")"
+	git update-ref ORIG_HEAD $orig_head
+}
+
+get_missing_commit_check_level () {
+	check_level=$(git config --get rebase.missingCommitsCheck)
+	check_level=${check_level:-ignore}
+	# Don't be case sensitive
+	printf '%s' "$check_level" | tr 'A-Z' 'a-z'
+}
+
+# Initiate an action. If the cannot be any
+# further action it  may exec a command
+# or exit and not return.
+#
+# TODO: Consider a cleaner return model so it
+# never exits and always return 0 if process
+# is complete.
+#
+# Parameter 1 is the action to initiate.
+#
+# Returns 0 if the action was able to complete
+# and if 1 if further processing is required.
+initiate_action () {
+	case "$1" in
+	continue)
+		exec git rebase--helper ${force_rebase:+--no-ff} $allow_empty_message \
+		     --continue
+		;;
+	skip)
+		git rerere clear
+		exec git rebase--helper ${force_rebase:+--no-ff} $allow_empty_message \
+		     --continue
+		;;
+	edit-todo)
+		git stripspace --strip-comments <"$todo" >"$todo".new
+		mv -f "$todo".new "$todo"
+		collapse_todo_ids
+		append_todo_help
+		gettext "
+You are editing the todo file of an ongoing interactive rebase.
+To continue rebase after editing, run:
+    git rebase --continue
+
+" | git stripspace --comment-lines >>"$todo"
+
+		git_sequence_editor "$todo" ||
+			die "$(gettext "Could not execute editor")"
+		expand_todo_ids
+
+		exit
+		;;
+	show-current-patch)
+		exec git show REBASE_HEAD --
+		;;
+	*)
+		return 1 # continue
+		;;
+	esac
+}
+
+setup_reflog_action () {
+	comment_for_reflog start
+
+	if test ! -z "$switch_to"
+	then
+		GIT_REFLOG_ACTION="$GIT_REFLOG_ACTION: checkout $switch_to"
+		output git checkout "$switch_to" -- ||
+			die "$(eval_gettext "Could not checkout \$switch_to")"
+
+		comment_for_reflog start
+	fi
+}
+
+init_basic_state () {
+	orig_head=$(git rev-parse --verify HEAD) || die "$(gettext "No HEAD?")"
+	mkdir -p "$state_dir" || die "$(eval_gettext "Could not create temporary \$state_dir")"
+	rm -f "$(git rev-parse --git-path REBASE_HEAD)"
+
+	: > "$state_dir"/interactive || die "$(gettext "Could not mark as interactive")"
+	write_basic_state
+}
+
+init_revisions_and_shortrevisions () {
+	shorthead=$(git rev-parse --short $orig_head)
+	shortonto=$(git rev-parse --short $onto)
+	if test -z "$rebase_root"
+		# this is now equivalent to ! -z "$upstream"
+	then
+		shortupstream=$(git rev-parse --short $upstream)
+		revisions=$upstream...$orig_head
+		shortrevisions=$shortupstream..$shorthead
+	else
+		revisions=$onto...$orig_head
+		shortrevisions=$shorthead
+		test -z "$squash_onto" ||
+		echo "$squash_onto" >"$state_dir"/squash-onto
+	fi
+}
+
+complete_action() {
+	test -s "$todo" || echo noop >> "$todo"
+	test -z "$autosquash" || git rebase--helper --rearrange-squash || exit
+	test -n "$cmd" && git rebase--helper --add-exec-commands "$cmd"
+
+	todocount=$(git stripspace --strip-comments <"$todo" | wc -l)
+	todocount=${todocount##* }
+
+cat >>"$todo" <<EOF
+
+$comment_char $(eval_ngettext \
+	"Rebase \$shortrevisions onto \$shortonto (\$todocount command)" \
+	"Rebase \$shortrevisions onto \$shortonto (\$todocount commands)" \
+	"$todocount")
+EOF
+	append_todo_help
+	gettext "
+	However, if you remove everything, the rebase will be aborted.
+
+	" | git stripspace --comment-lines >>"$todo"
+
+	if test -z "$keep_empty"
+	then
+		printf '%s\n' "$comment_char $(gettext "Note that empty commits are commented out")" >>"$todo"
+	fi
+
+
+	has_action "$todo" ||
+		return 2
+
+	cp "$todo" "$todo".backup
+	collapse_todo_ids
+	git_sequence_editor "$todo" ||
+		die_abort "$(gettext "Could not execute editor")"
+
+	has_action "$todo" ||
+		return 2
+
+	git rebase--helper --check-todo-list || {
+		ret=$?
+		checkout_onto
+		exit $ret
+	}
+
+	expand_todo_ids
+
+	test -n "$force_rebase" ||
+	onto="$(git rebase--helper --skip-unnecessary-picks)" ||
+	die "Could not skip unnecessary pick commands"
+
+	checkout_onto
+	require_clean_work_tree "rebase"
+	exec git rebase--helper ${force_rebase:+--no-ff} $allow_empty_message \
+	     --continue
+}
+
+git_rebase__interactive () {
+	initiate_action "$action"
+	ret=$?
+	if test $ret = 0; then
+		return 0
+	fi
+
+	setup_reflog_action
+	init_basic_state
+
+	init_revisions_and_shortrevisions
+
+	git rebase--helper --make-script ${keep_empty:+--keep-empty} \
+		${rebase_merges:+--rebase-merges} \
+		${rebase_cousins:+--rebase-cousins} \
+		$revisions ${restrict_revision+^$restrict_revision} >"$todo" ||
+	die "$(gettext "Could not generate todo list")"
+
+	complete_action
+}

From 774a0ca0ee8e383d3accbf6bf8d7973f2986cb63 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 24 Aug 2018 16:21:19 +0200
Subject: [PATCH 2/6] "fixup! builtin rebase: support `keep-empty` option"

This *would* be a fixup commit, except that we want to avoid rewriting
commits that we merged from upstream's `pu` branch. Instead, we want to
send a new iteration, and then re-merge the new iteration once it made
it into the `pu` branch.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 builtin/rebase.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/builtin/rebase.c b/builtin/rebase.c
index 029d04e9fc..2b1747249d 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -1025,7 +1025,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			 &options.allow_rerere_autoupdate,
 			 N_("allow rerere to update index  with resolved "
 			    "conflict")),
-		OPT_BOOL(0, "keep-empty", &options.keep_empty,
+		OPT_BOOL('k', "keep-empty", &options.keep_empty,
 			 N_("preserve empty commits during rebase")),
 		OPT_BOOL(0, "autosquash", &options.autosquash,
 			 N_("move commits that begin with "

From dc25b6cff07003daea5d1a42d39c6a3792c455f8 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 24 Aug 2018 15:07:41 +0200
Subject: [PATCH 3/6] non-builtin rebase: use non-builtin interactive backend

We recently converted both the `git rebase` and the `git rebase -i`
command from Unix shell scripts to builtins.

The former has a safety valve allowing to fall back to the scripted
`rebase`, just in case that there is a bug in the builtin `rebase`:
setting the config variable `rebase.useBuiltin` to `false` will
fall back to using the scripted version.

The latter did not have such a safety hatch.

Let's reinstate the scripted interactive rebase backend so that `rebase.useBuiltin=false` will not use the builtin interactive rebase,
just in case that an end user runs into a bug with the builtin version
and needs to get out of the fix really quickly.

This is necessary because Git for Windows wants to ship the builtin
rebase/interactive rebase earlier than core Git: Git for Windows
v2.19.0 will come with the option of a drastically faster (if a lot
less battle-tested) `git rebase`/`git rebase -i`.

As the file name `git-rebase--interactive` is already in use, let's
rename the scripted backend to `git-legacy-rebase--interactive`.

A couple of additional touch-ups are needed (such as teaching the
builtin `rebase--interactive`, which assumed the role of the
`rebase--helper`, to perform the two tricks to skip the unnecessary
picks and to generate a new todo list) to make things work again.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 .gitignore                                    |  1 +
 Makefile                                      |  1 +
 builtin/rebase--interactive.c                 | 18 +++++++-
 ...ve.sh => git-legacy-rebase--interactive.sh | 20 ++++-----
 git-legacy-rebase.sh                          | 42 ++++---------------
 sequencer.c                                   |  2 +-
 sequencer.h                                   |  2 +
 7 files changed, 41 insertions(+), 45 deletions(-)
 rename git-rebase--interactive.sh => git-legacy-rebase--interactive.sh (91%)

diff --git a/.gitignore b/.gitignore
index 52ac3d2117..81c2694c57 100644
--- a/.gitignore
+++ b/.gitignore
@@ -79,6 +79,7 @@
 /git-interpret-trailers
 /git-instaweb
 /git-legacy-rebase
+/git-legacy-rebase--interactive
 /git-log
 /git-ls-files
 /git-ls-remote
diff --git a/Makefile b/Makefile
index 3ca69336a1..e2790570d0 100644
--- a/Makefile
+++ b/Makefile
@@ -620,6 +620,7 @@ SCRIPT_SH += git-request-pull.sh
 SCRIPT_SH += git-submodule.sh
 SCRIPT_SH += git-web--browse.sh
 
+SCRIPT_LIB += git-legacy-rebase--interactive
 SCRIPT_LIB += git-mergetool--lib
 SCRIPT_LIB += git-parse-remote
 SCRIPT_LIB += git-rebase--am
diff --git a/builtin/rebase--interactive.c b/builtin/rebase--interactive.c
index 9c953b55bd..551faba558 100644
--- a/builtin/rebase--interactive.c
+++ b/builtin/rebase--interactive.c
@@ -141,7 +141,8 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
 	char *raw_strategies = NULL;
 	enum {
 		NONE = 0, CONTINUE, SKIP, EDIT_TODO, SHOW_CURRENT_PATCH,
-		SHORTEN_OIDS, EXPAND_OIDS, CHECK_TODO_LIST, REARRANGE_SQUASH, ADD_EXEC
+		SHORTEN_OIDS, EXPAND_OIDS, CHECK_TODO_LIST, REARRANGE_SQUASH, ADD_EXEC,
+		MAKE_SCRIPT, SKIP_UNNECESSARY_PICKS,
 	} command = 0;
 	struct option options[] = {
 		OPT_BOOL(0, "ff", &opts.allow_ff, N_("allow fast-forward")),
@@ -191,6 +192,10 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
 		OPT_STRING(0, "onto-name", &onto_name, N_("onto-name"), N_("onto name")),
 		OPT_STRING(0, "cmd", &cmd, N_("cmd"), N_("the command to run")),
 		OPT_RERERE_AUTOUPDATE(&opts.allow_rerere_auto),
+		OPT_CMDMODE(0, "make-script", &command,
+			N_("make rebase script"), MAKE_SCRIPT),
+		OPT_CMDMODE(0, "skip-unnecessary-picks", &command,
+			N_("skip unnecessary picks"), SKIP_UNNECESSARY_PICKS),
 		OPT_END()
 	};
 
@@ -262,6 +267,17 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
 	case ADD_EXEC:
 		ret = sequencer_add_exec_commands(cmd);
 		break;
+	case MAKE_SCRIPT:
+		ret = sequencer_make_script(stdout, argc, argv, flags);
+		break;
+	case SKIP_UNNECESSARY_PICKS: {
+		struct object_id oid;
+
+		ret = skip_unnecessary_picks(&oid);
+		if (!ret)
+			printf("%s\n", oid_to_hex(&oid));
+		break;
+	}
 	default:
 		BUG("invalid command '%d'", command);
 	}
diff --git a/git-rebase--interactive.sh b/git-legacy-rebase--interactive.sh
similarity index 91%
rename from git-rebase--interactive.sh
rename to git-legacy-rebase--interactive.sh
index 299ded2137..9740875ad5 100644
--- a/git-rebase--interactive.sh
+++ b/git-legacy-rebase--interactive.sh
@@ -95,11 +95,11 @@ git_sequence_editor () {
 }
 
 expand_todo_ids() {
-	git rebase--helper --expand-ids
+	git rebase--interactive --expand-ids
 }
 
 collapse_todo_ids() {
-	git rebase--helper --shorten-ids
+	git rebase--interactive --shorten-ids
 }
 
 # Switch to the branch in $into and notify it in the reflog
@@ -131,12 +131,12 @@ get_missing_commit_check_level () {
 initiate_action () {
 	case "$1" in
 	continue)
-		exec git rebase--helper ${force_rebase:+--no-ff} $allow_empty_message \
+		exec git rebase--interactive ${force_rebase:+--no-ff} $allow_empty_message \
 		     --continue
 		;;
 	skip)
 		git rerere clear
-		exec git rebase--helper ${force_rebase:+--no-ff} $allow_empty_message \
+		exec git rebase--interactive ${force_rebase:+--no-ff} $allow_empty_message \
 		     --continue
 		;;
 	edit-todo)
@@ -207,8 +207,8 @@ init_revisions_and_shortrevisions () {
 
 complete_action() {
 	test -s "$todo" || echo noop >> "$todo"
-	test -z "$autosquash" || git rebase--helper --rearrange-squash || exit
-	test -n "$cmd" && git rebase--helper --add-exec-commands "$cmd"
+	test -z "$autosquash" || git rebase--interactive --rearrange-squash || exit
+	test -n "$cmd" && git rebase--interactive --add-exec-commands --cmd "$cmd"
 
 	todocount=$(git stripspace --strip-comments <"$todo" | wc -l)
 	todocount=${todocount##* }
@@ -243,7 +243,7 @@ EOF
 	has_action "$todo" ||
 		return 2
 
-	git rebase--helper --check-todo-list || {
+	git rebase--interactive --check-todo-list || {
 		ret=$?
 		checkout_onto
 		exit $ret
@@ -252,12 +252,12 @@ EOF
 	expand_todo_ids
 
 	test -n "$force_rebase" ||
-	onto="$(git rebase--helper --skip-unnecessary-picks)" ||
+	onto="$(git rebase--interactive --skip-unnecessary-picks)" ||
 	die "Could not skip unnecessary pick commands"
 
 	checkout_onto
 	require_clean_work_tree "rebase"
-	exec git rebase--helper ${force_rebase:+--no-ff} $allow_empty_message \
+	exec git rebase--interactive ${force_rebase:+--no-ff} $allow_empty_message \
 	     --continue
 }
 
@@ -273,7 +273,7 @@ git_rebase__interactive () {
 
 	init_revisions_and_shortrevisions
 
-	git rebase--helper --make-script ${keep_empty:+--keep-empty} \
+	git rebase--interactive --make-script ${keep_empty:+--keep-empty} \
 		${rebase_merges:+--rebase-merges} \
 		${rebase_cousins:+--rebase-cousins} \
 		$revisions ${restrict_revision+^$restrict_revision} >"$todo" ||
diff --git a/git-legacy-rebase.sh b/git-legacy-rebase.sh
index 7600765f54..4312e69c6b 100755
--- a/git-legacy-rebase.sh
+++ b/git-legacy-rebase.sh
@@ -135,37 +135,6 @@ finish_rebase () {
 	rm -rf "$state_dir"
 }
 
-run_interactive () {
-	GIT_CHERRY_PICK_HELP="$resolvemsg"
-	export GIT_CHERRY_PICK_HELP
-
-	test -n "$keep_empty" && keep_empty="--keep-empty"
-	test -n "$rebase_merges" && rebase_merges="--rebase-merges"
-	test -n "$rebase_cousins" && rebase_cousins="--rebase-cousins"
-	test -n "$autosquash" && autosquash="--autosquash"
-	test -n "$verbose" && verbose="--verbose"
-	test -n "$force_rebase" && force_rebase="--no-ff"
-	test -n "$restrict_revision" && \
-		restrict_revision="--restrict-revision=^$restrict_revision"
-	test -n "$upstream" && upstream="--upstream=$upstream"
-	test -n "$onto" && onto="--onto=$onto"
-	test -n "$squash_onto" && squash_onto="--squash-onto=$squash_onto"
-	test -n "$onto_name" && onto_name="--onto-name=$onto_name"
-	test -n "$head_name" && head_name="--head-name=$head_name"
-	test -n "$strategy" && strategy="--strategy=$strategy"
-	test -n "$strategy_opts" && strategy_opts="--strategy-opts=$strategy_opts"
-	test -n "$switch_to" && switch_to="--switch-to=$switch_to"
-	test -n "$cmd" && cmd="--cmd=$cmd"
-	test -n "$action" && action="--$action"
-
-	exec git rebase--interactive "$action" "$keep_empty" "$rebase_merges" "$rebase_cousins" \
-		"$upstream" "$onto" "$squash_onto" "$restrict_revision" \
-		"$allow_empty_message" "$autosquash" "$verbose" \
-		"$force_rebase" "$onto_name" "$head_name" "$strategy" \
-		"$strategy_opts" "$cmd" "$switch_to" \
-		"$allow_rerere_autoupdate" "$gpg_sign_opt" "$signoff"
-}
-
 run_specific_rebase () {
 	if [ "$interactive_rebase" = implied ]; then
 		GIT_EDITOR=:
@@ -175,7 +144,9 @@ run_specific_rebase () {
 
 	if test -n "$interactive_rebase" -a -z "$preserve_merges"
 	then
-		run_interactive
+		. git-legacy-rebase--$type
+
+		git_rebase__$type
 	else
 		. git-rebase--$type
 
@@ -195,7 +166,12 @@ run_specific_rebase () {
 	then
 		apply_autostash &&
 		rm -rf "$state_dir" &&
-		die "Nothing to do"
+		if test -n "$interactive_rebase" -a -z "$preserve_merges"
+		then
+			die "error: nothing to do"
+		else
+			die "Nothing to do"
+		fi
 	fi
 	exit $ret
 }
diff --git a/sequencer.c b/sequencer.c
index ad2193507b..f312ce123e 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -4637,7 +4637,7 @@ static int rewrite_file(const char *path, const char *buf, size_t len)
 }
 
 /* skip picking commits whose parents are unchanged */
-static int skip_unnecessary_picks(struct object_id *output_oid)
+int skip_unnecessary_picks(struct object_id *output_oid)
 {
 	const char *todo_file = rebase_path_todo();
 	struct strbuf buf = STRBUF_INIT;
diff --git a/sequencer.h b/sequencer.h
index 4919743552..0a3f212403 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -128,3 +128,5 @@ void print_commit_summary(const char *prefix, const struct object_id *oid,
 void parse_strategy_opts(struct replay_opts *opts, char *raw_opts);
 int write_basic_state(struct replay_opts *opts, const char *head_name,
 		      const char *onto, const char *orig_head);
+
+int skip_unnecessary_picks(struct object_id *output_oid);
\ No newline at end of file

From 4f49e257176cf7e231aeb8a2c4642b9a974a9177 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 24 Aug 2018 15:14:04 +0200
Subject: [PATCH 4/6] Add back the original, scripted `git stash`

This simply copies the version as of v2.19.0-rc0 verbatim. As of now,
it is not hooked up.

The next commit will change the builtin `stash` to hand off to the
scripted `git stash` when `stash.useBuiltin=false`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 git-stash.sh | 752 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 752 insertions(+)
 create mode 100755 git-stash.sh

diff --git a/git-stash.sh b/git-stash.sh
new file mode 100755
index 0000000000..94793c1a91
--- /dev/null
+++ b/git-stash.sh
@@ -0,0 +1,752 @@
+#!/bin/sh
+# Copyright (c) 2007, Nanako Shiraishi
+
+dashless=$(basename "$0" | sed -e 's/-/ /')
+USAGE="list [<options>]
+   or: $dashless show [<stash>]
+   or: $dashless drop [-q|--quiet] [<stash>]
+   or: $dashless ( pop | apply ) [--index] [-q|--quiet] [<stash>]
+   or: $dashless branch <branchname> [<stash>]
+   or: $dashless save [--patch] [-k|--[no-]keep-index] [-q|--quiet]
+		      [-u|--include-untracked] [-a|--all] [<message>]
+   or: $dashless [push [--patch] [-k|--[no-]keep-index] [-q|--quiet]
+		       [-u|--include-untracked] [-a|--all] [-m <message>]
+		       [-- <pathspec>...]]
+   or: $dashless clear"
+
+SUBDIRECTORY_OK=Yes
+OPTIONS_SPEC=
+START_DIR=$(pwd)
+. git-sh-setup
+require_work_tree
+prefix=$(git rev-parse --show-prefix) || exit 1
+cd_to_toplevel
+
+TMP="$GIT_DIR/.git-stash.$$"
+TMPindex=${GIT_INDEX_FILE-"$(git rev-parse --git-path index)"}.stash.$$
+trap 'rm -f "$TMP-"* "$TMPindex"' 0
+
+ref_stash=refs/stash
+
+if git config --get-colorbool color.interactive; then
+       help_color="$(git config --get-color color.interactive.help 'red bold')"
+       reset_color="$(git config --get-color '' reset)"
+else
+       help_color=
+       reset_color=
+fi
+
+no_changes () {
+	git diff-index --quiet --cached HEAD --ignore-submodules -- "$@" &&
+	git diff-files --quiet --ignore-submodules -- "$@" &&
+	(test -z "$untracked" || test -z "$(untracked_files "$@")")
+}
+
+untracked_files () {
+	if test "$1" = "-z"
+	then
+		shift
+		z=-z
+	else
+		z=
+	fi
+	excl_opt=--exclude-standard
+	test "$untracked" = "all" && excl_opt=
+	git ls-files -o $z $excl_opt -- "$@"
+}
+
+clear_stash () {
+	if test $# != 0
+	then
+		die "$(gettext "git stash clear with parameters is unimplemented")"
+	fi
+	if current=$(git rev-parse --verify --quiet $ref_stash)
+	then
+		git update-ref -d $ref_stash $current
+	fi
+}
+
+create_stash () {
+	stash_msg=
+	untracked=
+	while test $# != 0
+	do
+		case "$1" in
+		-m|--message)
+			shift
+			stash_msg=${1?"BUG: create_stash () -m requires an argument"}
+			;;
+		-m*)
+			stash_msg=${1#-m}
+			;;
+		--message=*)
+			stash_msg=${1#--message=}
+			;;
+		-u|--include-untracked)
+			shift
+			untracked=${1?"BUG: create_stash () -u requires an argument"}
+			;;
+		--)
+			shift
+			break
+			;;
+		esac
+		shift
+	done
+
+	git update-index -q --refresh
+	if no_changes "$@"
+	then
+		exit 0
+	fi
+
+	# state of the base commit
+	if b_commit=$(git rev-parse --verify HEAD)
+	then
+		head=$(git rev-list --oneline -n 1 HEAD --)
+	else
+		die "$(gettext "You do not have the initial commit yet")"
+	fi
+
+	if branch=$(git symbolic-ref -q HEAD)
+	then
+		branch=${branch#refs/heads/}
+	else
+		branch='(no branch)'
+	fi
+	msg=$(printf '%s: %s' "$branch" "$head")
+
+	# state of the index
+	i_tree=$(git write-tree) &&
+	i_commit=$(printf 'index on %s\n' "$msg" |
+		git commit-tree $i_tree -p $b_commit) ||
+		die "$(gettext "Cannot save the current index state")"
+
+	if test -n "$untracked"
+	then
+		# Untracked files are stored by themselves in a parentless commit, for
+		# ease of unpacking later.
+		u_commit=$(
+			untracked_files -z "$@" | (
+				GIT_INDEX_FILE="$TMPindex" &&
+				export GIT_INDEX_FILE &&
+				rm -f "$TMPindex" &&
+				git update-index -z --add --remove --stdin &&
+				u_tree=$(git write-tree) &&
+				printf 'untracked files on %s\n' "$msg" | git commit-tree $u_tree  &&
+				rm -f "$TMPindex"
+		) ) || die "$(gettext "Cannot save the untracked files")"
+
+		untracked_commit_option="-p $u_commit";
+	else
+		untracked_commit_option=
+	fi
+
+	if test -z "$patch_mode"
+	then
+
+		# state of the working tree
+		w_tree=$( (
+			git read-tree --index-output="$TMPindex" -m $i_tree &&
+			GIT_INDEX_FILE="$TMPindex" &&
+			export GIT_INDEX_FILE &&
+			git diff-index --name-only -z HEAD -- "$@" >"$TMP-stagenames" &&
+			git update-index -z --add --remove --stdin <"$TMP-stagenames" &&
+			git write-tree &&
+			rm -f "$TMPindex"
+		) ) ||
+			die "$(gettext "Cannot save the current worktree state")"
+
+	else
+
+		rm -f "$TMP-index" &&
+		GIT_INDEX_FILE="$TMP-index" git read-tree HEAD &&
+
+		# find out what the user wants
+		GIT_INDEX_FILE="$TMP-index" \
+			git add--interactive --patch=stash -- "$@" &&
+
+		# state of the working tree
+		w_tree=$(GIT_INDEX_FILE="$TMP-index" git write-tree) ||
+		die "$(gettext "Cannot save the current worktree state")"
+
+		git diff-tree -p HEAD $w_tree -- >"$TMP-patch" &&
+		test -s "$TMP-patch" ||
+		die "$(gettext "No changes selected")"
+
+		rm -f "$TMP-index" ||
+		die "$(gettext "Cannot remove temporary index (can't happen)")"
+
+	fi
+
+	# create the stash
+	if test -z "$stash_msg"
+	then
+		stash_msg=$(printf 'WIP on %s' "$msg")
+	else
+		stash_msg=$(printf 'On %s: %s' "$branch" "$stash_msg")
+	fi
+	w_commit=$(printf '%s\n' "$stash_msg" |
+	git commit-tree $w_tree -p $b_commit -p $i_commit $untracked_commit_option) ||
+	die "$(gettext "Cannot record working tree state")"
+}
+
+store_stash () {
+	while test $# != 0
+	do
+		case "$1" in
+		-m|--message)
+			shift
+			stash_msg="$1"
+			;;
+		-m*)
+			stash_msg=${1#-m}
+			;;
+		--message=*)
+			stash_msg=${1#--message=}
+			;;
+		-q|--quiet)
+			quiet=t
+			;;
+		*)
+			break
+			;;
+		esac
+		shift
+	done
+	test $# = 1 ||
+	die "$(eval_gettext "\"$dashless store\" requires one <commit> argument")"
+
+	w_commit="$1"
+	if test -z "$stash_msg"
+	then
+		stash_msg="Created via \"git stash store\"."
+	fi
+
+	git update-ref --create-reflog -m "$stash_msg" $ref_stash $w_commit
+	ret=$?
+	test $ret != 0 && test -z "$quiet" &&
+	die "$(eval_gettext "Cannot update \$ref_stash with \$w_commit")"
+	return $ret
+}
+
+push_stash () {
+	keep_index=
+	patch_mode=
+	untracked=
+	stash_msg=
+	while test $# != 0
+	do
+		case "$1" in
+		-k|--keep-index)
+			keep_index=t
+			;;
+		--no-keep-index)
+			keep_index=n
+			;;
+		-p|--patch)
+			patch_mode=t
+			# only default to keep if we don't already have an override
+			test -z "$keep_index" && keep_index=t
+			;;
+		-q|--quiet)
+			GIT_QUIET=t
+			;;
+		-u|--include-untracked)
+			untracked=untracked
+			;;
+		-a|--all)
+			untracked=all
+			;;
+		-m|--message)
+			shift
+			test -z ${1+x} && usage
+			stash_msg=$1
+			;;
+		-m*)
+			stash_msg=${1#-m}
+			;;
+		--message=*)
+			stash_msg=${1#--message=}
+			;;
+		--help)
+			show_help
+			;;
+		--)
+			shift
+			break
+			;;
+		-*)
+			option="$1"
+			eval_gettextln "error: unknown option for 'stash push': \$option"
+			usage
+			;;
+		*)
+			break
+			;;
+		esac
+		shift
+	done
+
+	eval "set $(git rev-parse --sq --prefix "$prefix" -- "$@")"
+
+	if test -n "$patch_mode" && test -n "$untracked"
+	then
+		die "$(gettext "Can't use --patch and --include-untracked or --all at the same time")"
+	fi
+
+	test -n "$untracked" || git ls-files --error-unmatch -- "$@" >/dev/null || exit 1
+
+	git update-index -q --refresh
+	if no_changes "$@"
+	then
+		say "$(gettext "No local changes to save")"
+		exit 0
+	fi
+
+	git reflog exists $ref_stash ||
+		clear_stash || die "$(gettext "Cannot initialize stash")"
+
+	create_stash -m "$stash_msg" -u "$untracked" -- "$@"
+	store_stash -m "$stash_msg" -q $w_commit ||
+	die "$(gettext "Cannot save the current status")"
+	say "$(eval_gettext "Saved working directory and index state \$stash_msg")"
+
+	if test -z "$patch_mode"
+	then
+		test "$untracked" = "all" && CLEAN_X_OPTION=-x || CLEAN_X_OPTION=
+		if test -n "$untracked" && test $# = 0
+		then
+			git clean --force --quiet -d $CLEAN_X_OPTION
+		fi
+
+		if test $# != 0
+		then
+			test -z "$untracked" && UPDATE_OPTION="-u" || UPDATE_OPTION=
+			test "$untracked" = "all" && FORCE_OPTION="--force" || FORCE_OPTION=
+			git add $UPDATE_OPTION $FORCE_OPTION -- "$@"
+			git diff-index -p --cached --binary HEAD -- "$@" |
+			git apply --index -R
+		else
+			git reset --hard -q
+		fi
+
+		if test "$keep_index" = "t" && test -n "$i_tree"
+		then
+			git read-tree --reset $i_tree
+			git ls-files -z --modified -- "$@" |
+			git checkout-index -z --force --stdin
+		fi
+	else
+		git apply -R < "$TMP-patch" ||
+		die "$(gettext "Cannot remove worktree changes")"
+
+		if test "$keep_index" != "t"
+		then
+			git reset -q -- "$@"
+		fi
+	fi
+}
+
+save_stash () {
+	push_options=
+	while test $# != 0
+	do
+		case "$1" in
+		--)
+			shift
+			break
+			;;
+		-*)
+			# pass all options through to push_stash
+			push_options="$push_options $1"
+			;;
+		*)
+			break
+			;;
+		esac
+		shift
+	done
+
+	stash_msg="$*"
+
+	if test -z "$stash_msg"
+	then
+		push_stash $push_options
+	else
+		push_stash $push_options -m "$stash_msg"
+	fi
+}
+
+have_stash () {
+	git rev-parse --verify --quiet $ref_stash >/dev/null
+}
+
+list_stash () {
+	have_stash || return 0
+	git log --format="%gd: %gs" -g --first-parent -m "$@" $ref_stash --
+}
+
+show_stash () {
+	ALLOW_UNKNOWN_FLAGS=t
+	assert_stash_like "$@"
+
+	if test -z "$FLAGS"
+	then
+		if test "$(git config --bool stash.showStat || echo true)" = "true"
+		then
+			FLAGS=--stat
+		fi
+
+		if test "$(git config --bool stash.showPatch || echo false)" = "true"
+		then
+			FLAGS=${FLAGS}${FLAGS:+ }-p
+		fi
+
+		if test -z "$FLAGS"
+		then
+			return 0
+		fi
+	fi
+
+	git diff ${FLAGS} $b_commit $w_commit
+}
+
+show_help () {
+	exec git help stash
+	exit 1
+}
+
+#
+# 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 ${REV} looks like a stash ref
+#   s is set to the SHA1 of the stash commit
+#   w_commit is set to the commit containing the working tree
+#   b_commit is set to the base commit
+#   i_commit is set to the commit containing the index tree
+#   u_commit is set to the commit containing the untracked files tree
+#   w_tree is set to the working tree
+#   b_tree is set to the base tree
+#   i_tree is set to the index tree
+#   u_tree is set to the untracked files tree
+#
+#   GIT_QUIET is set to t if -q is specified
+#   INDEX_OPTION is set to --index if --index is specified.
+#   FLAGS is set to the remaining flags (if allowed)
+#
+# dies if:
+#   * too many revisions specified
+#   * no revision is specified and there is no stash stack
+#   * a revision is specified which cannot be resolve to a SHA1
+#   * a non-existent stash reference is specified
+#   * unknown flags were set and ALLOW_UNKNOWN_FLAGS is not "t"
+#
+
+parse_flags_and_rev()
+{
+	test "$PARSE_CACHE" = "$*" && return 0 # optimisation
+	PARSE_CACHE="$*"
+
+	IS_STASH_LIKE=
+	IS_STASH_REF=
+	INDEX_OPTION=
+	s=
+	w_commit=
+	b_commit=
+	i_commit=
+	u_commit=
+	w_tree=
+	b_tree=
+	i_tree=
+	u_tree=
+
+	FLAGS=
+	REV=
+	for opt
+	do
+		case "$opt" in
+			-q|--quiet)
+				GIT_QUIET=-t
+			;;
+			--index)
+				INDEX_OPTION=--index
+			;;
+			--help)
+				show_help
+			;;
+			-*)
+				test "$ALLOW_UNKNOWN_FLAGS" = t ||
+					die "$(eval_gettext "unknown option: \$opt")"
+				FLAGS="${FLAGS}${FLAGS:+ }$opt"
+			;;
+			*)
+				REV="${REV}${REV:+ }'$opt'"
+			;;
+		esac
+	done
+
+	eval set -- $REV
+
+	case $# in
+		0)
+			have_stash || die "$(gettext "No stash entries found.")"
+			set -- ${ref_stash}@{0}
+		;;
+		1)
+			:
+		;;
+		*)
+			die "$(eval_gettext "Too many revisions specified: \$REV")"
+		;;
+	esac
+
+	case "$1" in
+		*[!0-9]*)
+			:
+		;;
+		*)
+			set -- "${ref_stash}@{$1}"
+		;;
+	esac
+
+	REV=$(git rev-parse --symbolic --verify --quiet "$1") || {
+		reference="$1"
+		die "$(eval_gettext "\$reference is not a valid reference")"
+	}
+
+	i_commit=$(git rev-parse --verify --quiet "$REV^2") &&
+	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
+
+	u_commit=$(git rev-parse --verify --quiet "$REV^3") &&
+	u_tree=$(git rev-parse "$REV^3:" 2>/dev/null)
+}
+
+is_stash_like()
+{
+	parse_flags_and_rev "$@"
+	test -n "$IS_STASH_LIKE"
+}
+
+assert_stash_like() {
+	is_stash_like "$@" || {
+		args="$*"
+		die "$(eval_gettext "'\$args' is not a stash-like commit")"
+	}
+}
+
+is_stash_ref() {
+	is_stash_like "$@" && test -n "$IS_STASH_REF"
+}
+
+assert_stash_ref() {
+	is_stash_ref "$@" || {
+		args="$*"
+		die "$(eval_gettext "'\$args' is not a stash reference")"
+	}
+}
+
+apply_stash () {
+
+	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 $status
+	fi
+}
+
+pop_stash() {
+	assert_stash_ref "$@"
+
+	if apply_stash "$@"
+	then
+		drop_stash "$@"
+	else
+		status=$?
+		say "$(gettext "The stash entry is kept in case you need it again.")"
+		exit $status
+	fi
+}
+
+drop_stash () {
+	assert_stash_ref "$@"
+
+	git reflog delete --updateref --rewrite "${REV}" &&
+		say "$(eval_gettext "Dropped \${REV} (\$s)")" ||
+		die "$(eval_gettext "\${REV}: Could not drop stash entry")"
+
+	# clear_stash if we just dropped the last stash entry
+	git rev-parse --verify --quiet "$ref_stash@{0}" >/dev/null ||
+	clear_stash
+}
+
+apply_to_branch () {
+	test -n "$1" || die "$(gettext "No branch name specified")"
+	branch=$1
+	shift 1
+
+	set -- --index "$@"
+	assert_stash_like "$@"
+
+	git checkout -b $branch $REV^ &&
+	apply_stash "$@" && {
+		test -z "$IS_STASH_REF" || drop_stash "$@"
+	}
+}
+
+test "$1" = "-p" && set "push" "$@"
+
+PARSE_CACHE='--not-parsed'
+# The default command is "push" if nothing but options are given
+seen_non_option=
+for opt
+do
+	case "$opt" in
+	--) break ;;
+	-*) ;;
+	*) seen_non_option=t; break ;;
+	esac
+done
+
+test -n "$seen_non_option" || set "push" "$@"
+
+# Main command set
+case "$1" in
+list)
+	shift
+	list_stash "$@"
+	;;
+show)
+	shift
+	show_stash "$@"
+	;;
+save)
+	shift
+	save_stash "$@"
+	;;
+push)
+	shift
+	push_stash "$@"
+	;;
+apply)
+	shift
+	apply_stash "$@"
+	;;
+clear)
+	shift
+	clear_stash "$@"
+	;;
+create)
+	shift
+	create_stash -m "$*" && echo "$w_commit"
+	;;
+store)
+	shift
+	store_stash "$@"
+	;;
+drop)
+	shift
+	drop_stash "$@"
+	;;
+pop)
+	shift
+	pop_stash "$@"
+	;;
+branch)
+	shift
+	apply_to_branch "$@"
+	;;
+*)
+	case $# in
+	0)
+		push_stash &&
+		say "$(gettext "(To restore them type \"git stash apply\")")"
+		;;
+	*)
+		usage
+	esac
+	;;
+esac

From f237751535719ef3dfd4ed3cec012a3e36ddaae3 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 24 Aug 2018 15:07:41 +0200
Subject: [PATCH 5/6] stash: optionally use the scripted version again

We recently converted the `git stash` command from Unix shell scripts
to builtins.

Just like we have `rebase.useBuiltin` to fall back to the scripted
rebase, to give end users a way out when they discover a bug in the
builtin command, this commit adds support for `stash.useBuiltin`.

This is necessary because Git for Windows wants to ship the builtin
stash earlier than core Git: Git for Windows v2.19.0 will come with
the option of a drastically faster (if a lot less battle-tested)
`git stash`.

As the file name `git-stash` is already in use, let's rename the
scripted backend to `git-legacy-stash`.

To make the test suite pass with `stash.useBuiltin=false`, this commit
also backports rudimentary support for `-q` (but only *just* enough
to appease the test suite), and adds a super-ugly hack to force exit
code 129 for `git stash -h`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 .gitignore                          |  1 +
 Makefile                            |  1 +
 builtin/stash.c                     | 35 +++++++++++++++++++++++++++++
 git-stash.sh => git-legacy-stash.sh | 34 +++++++++++++++++++++++++---
 git-sh-setup.sh                     |  1 +
 git.c                               |  7 +++++-
 6 files changed, 75 insertions(+), 4 deletions(-)
 rename git-stash.sh => git-legacy-stash.sh (97%)

diff --git a/.gitignore b/.gitignore
index 81c2694c57..a371024425 100644
--- a/.gitignore
+++ b/.gitignore
@@ -80,6 +80,7 @@
 /git-instaweb
 /git-legacy-rebase
 /git-legacy-rebase--interactive
+/git-legacy-stash
 /git-log
 /git-ls-files
 /git-ls-remote
diff --git a/Makefile b/Makefile
index e2790570d0..221410e7ba 100644
--- a/Makefile
+++ b/Makefile
@@ -615,6 +615,7 @@ SCRIPT_SH += git-merge-resolve.sh
 SCRIPT_SH += git-mergetool.sh
 SCRIPT_SH += git-quiltimport.sh
 SCRIPT_SH += git-legacy-rebase.sh
+SCRIPT_SH += git-legacy-stash.sh
 SCRIPT_SH += git-remote-testgit.sh
 SCRIPT_SH += git-request-pull.sh
 SCRIPT_SH += git-submodule.sh
diff --git a/builtin/stash.c b/builtin/stash.c
index dd1084afd4..dfabc0c798 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -13,6 +13,7 @@
 #include "revision.h"
 #include "log-tree.h"
 #include "diffcore.h"
+#include "exec-cmd.h"
 
 static const char * const git_stash_usage[] = {
 	N_("git stash list [<options>]"),
@@ -1476,6 +1477,26 @@ static int save_stash(int argc, const char **argv, const char *prefix)
 	return ret;
 }
 
+static int use_builtin_stash(void)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+	struct strbuf out = STRBUF_INIT;
+	int ret;
+
+	argv_array_pushl(&cp.args,
+			 "config", "--bool", "stash.usebuiltin", NULL);
+	cp.git_cmd = 1;
+	if (capture_command(&cp, &out, 6)) {
+		strbuf_release(&out);
+		return 1;
+	}
+
+	strbuf_trim(&out);
+	ret = !strcmp("true", out.buf);
+	strbuf_release(&out);
+	return ret;
+}
+
 int cmd_stash(int argc, const char **argv, const char *prefix)
 {
 	int i = -1;
@@ -1487,6 +1508,20 @@ int cmd_stash(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
+	if (!use_builtin_stash()) {
+		const char *path = mkpath("%s/git-legacy-stash",
+					  git_exec_path());
+
+		if (sane_execvp(path, (char **)argv) < 0)
+			die_errno(_("could not exec %s"), path);
+		else
+			BUG("sane_execvp() returned???");
+	}
+
+	prefix = setup_git_directory();
+	trace_repo_setup(prefix);
+	setup_work_tree();
+
 	git_config(git_default_config, NULL);
 
 	argc = parse_options(argc, argv, prefix, options, git_stash_usage,
diff --git a/git-stash.sh b/git-legacy-stash.sh
similarity index 97%
rename from git-stash.sh
rename to git-legacy-stash.sh
index 94793c1a91..eed7da4884 100755
--- a/git-stash.sh
+++ b/git-legacy-stash.sh
@@ -66,6 +66,28 @@ clear_stash () {
 	fi
 }
 
+maybe_quiet () {
+	case "$1" in
+	--keep-stdout)
+		shift
+		if test -n "$GIT_QUIET"
+		then
+			eval "$@" 2>/dev/null
+		else
+			eval "$@"
+		fi
+		;;
+	*)
+		if test -n "$GIT_QUIET"
+		then
+			eval "$@" >/dev/null 2>&1
+		else
+			eval "$@"
+		fi
+		;;
+	esac
+}
+
 create_stash () {
 	stash_msg=
 	untracked=
@@ -95,15 +117,18 @@ create_stash () {
 	done
 
 	git update-index -q --refresh
-	if no_changes "$@"
+	if maybe_quiet no_changes "$@"
 	then
 		exit 0
 	fi
 
 	# state of the base commit
-	if b_commit=$(git rev-parse --verify HEAD)
+	if b_commit=$(maybe_quiet --keep-stdout git rev-parse --verify HEAD)
 	then
 		head=$(git rev-list --oneline -n 1 HEAD --)
+	elif test -n "$GIT_QUIET"
+	then
+		exit 1
 	else
 		die "$(gettext "You do not have the initial commit yet")"
 	fi
@@ -298,7 +323,7 @@ push_stash () {
 	test -n "$untracked" || git ls-files --error-unmatch -- "$@" >/dev/null || exit 1
 
 	git update-index -q --refresh
-	if no_changes "$@"
+	if maybe_quiet no_changes "$@"
 	then
 		say "$(gettext "No local changes to save")"
 		exit 0
@@ -353,6 +378,9 @@ save_stash () {
 	while test $# != 0
 	do
 		case "$1" in
+		-q|--quiet)
+			GIT_QUIET=t
+			;;
 		--)
 			shift
 			break
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 378928518b..10d9764185 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -101,6 +101,7 @@ $LONG_USAGE")"
 	case "$1" in
 		-h)
 		echo "$LONG_USAGE"
+		case "$0" in *git-legacy-stash) exit 129;; esac
 		exit
 	esac
 fi
diff --git a/git.c b/git.c
index 903aa16f0c..984c3ad7ab 100644
--- a/git.c
+++ b/git.c
@@ -550,7 +550,12 @@ 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", cmd_stash, RUN_SETUP | NEED_WORK_TREE },
+	/*
+	 * NEEDSWORK: Until the builtin stash is thoroughly robust and no
+	 * longer needs redirection to the stash shell script this is kept as
+	 * is, then should be changed to RUN_SETUP | NEED_WORK_TREE
+	 */
+	{ "stash", cmd_stash },
 	{ "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 	{ "stripspace", cmd_stripspace },
 	{ "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT },

From 50b06c8822ad34c57009804718cad006c11955ce Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 24 Aug 2018 17:51:56 +0200
Subject: [PATCH 6/6] stash/rebase: default to the non-builtin versions

The upcoming Git for Windows v2.19.0 wants to ship with the builtin
versions of stash, rebase and rebase -i. The reason: these are just *so
much faster*: t3400 and t3404 run about 60-70 percent faster, and t3903
even more than 80% faster.

However, these are still all pretty fresh, still being reviewed and
iterated on the Git mailing list.

So let's try to give users a way to test these (or to boldly use them
for their mission-critical tasks, as this here developer plans on
doing), but stay with the safe option by default: use the scripted
versions (which might be slow, but they are well tested).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 builtin/rebase.c | 2 +-
 builtin/stash.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/builtin/rebase.c b/builtin/rebase.c
index 029d04e9fc..ea556371e9 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -54,7 +54,7 @@ static int use_builtin_rebase(void)
 	cp.git_cmd = 1;
 	if (capture_command(&cp, &out, 6)) {
 		strbuf_release(&out);
-		return 1;
+		return 0;
 	}
 
 	strbuf_trim(&out);
diff --git a/builtin/stash.c b/builtin/stash.c
index dfabc0c798..ed669dae0f 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -1488,7 +1488,7 @@ static int use_builtin_stash(void)
 	cp.git_cmd = 1;
 	if (capture_command(&cp, &out, 6)) {
 		strbuf_release(&out);
-		return 1;
+		return 0;
 	}
 
 	strbuf_trim(&out);