merge(3p/git): Merge git upstream at v2.26.2 r/808

1 files changed, 1176 insertions, 0 deletions

diff --git a/third_party/git/add-interactive.c b/third_party/git/add-interactive.c
new file mode 100644
index 000000000000..4a9bf85cac03
--- /dev/null
+++ b/third_party/git/add-interactive.c
@@ -0,0 +1,1176 @@
+#include "cache.h"
+#include "add-interactive.h"
+#include "color.h"
+#include "config.h"
+#include "diffcore.h"
+#include "revision.h"
+#include "refs.h"
+#include "string-list.h"
+#include "lockfile.h"
+#include "dir.h"
+#include "run-command.h"
+
+static void init_color(struct repository *r, struct add_i_state *s,
+		       const char *slot_name, char *dst,
+		       const char *default_color)
+{
+	char *key = xstrfmt("color.interactive.%s", slot_name);
+	const char *value;
+
+	if (!s->use_color)
+		dst[0] = '\0';
+	else if (repo_config_get_value(r, key, &value) ||
+		 color_parse(value, dst))
+		strlcpy(dst, default_color, COLOR_MAXLEN);
+
+	free(key);
+}
+
+void init_add_i_state(struct add_i_state *s, struct repository *r)
+{
+	const char *value;
+
+	s->r = r;
+
+	if (repo_config_get_value(r, "color.interactive", &value))
+		s->use_color = -1;
+	else
+		s->use_color =
+			git_config_colorbool("color.interactive", value);
+	s->use_color = want_color(s->use_color);
+
+	init_color(r, s, "header", s->header_color, GIT_COLOR_BOLD);
+	init_color(r, s, "help", s->help_color, GIT_COLOR_BOLD_RED);
+	init_color(r, s, "prompt", s->prompt_color, GIT_COLOR_BOLD_BLUE);
+	init_color(r, s, "error", s->error_color, GIT_COLOR_BOLD_RED);
+	init_color(r, s, "reset", s->reset_color, GIT_COLOR_RESET);
+	init_color(r, s, "fraginfo", s->fraginfo_color,
+		   diff_get_color(s->use_color, DIFF_FRAGINFO));
+	init_color(r, s, "context", s->context_color,
+		diff_get_color(s->use_color, DIFF_CONTEXT));
+	init_color(r, s, "old", s->file_old_color,
+		diff_get_color(s->use_color, DIFF_FILE_OLD));
+	init_color(r, s, "new", s->file_new_color,
+		diff_get_color(s->use_color, DIFF_FILE_NEW));
+
+	FREE_AND_NULL(s->interactive_diff_filter);
+	git_config_get_string("interactive.difffilter",
+			      &s->interactive_diff_filter);
+
+	FREE_AND_NULL(s->interactive_diff_algorithm);
+	git_config_get_string("diff.algorithm",
+			      &s->interactive_diff_algorithm);
+
+	git_config_get_bool("interactive.singlekey", &s->use_single_key);
+}
+
+void clear_add_i_state(struct add_i_state *s)
+{
+	FREE_AND_NULL(s->interactive_diff_filter);
+	FREE_AND_NULL(s->interactive_diff_algorithm);
+	memset(s, 0, sizeof(*s));
+	s->use_color = -1;
+}
+
+/*
+ * A "prefix item list" is a list of items that are identified by a string, and
+ * a unique prefix (if any) is determined for each item.
+ *
+ * It is implemented in the form of a pair of `string_list`s, the first one
+ * duplicating the strings, with the `util` field pointing at a structure whose
+ * first field must be `size_t prefix_length`.
+ *
+ * That `prefix_length` field will be computed by `find_unique_prefixes()`; It
+ * will be set to zero if no valid, unique prefix could be found.
+ *
+ * The second `string_list` is called `sorted` and does _not_ duplicate the
+ * strings but simply reuses the first one's, with the `util` field pointing at
+ * the `string_item_list` of the first `string_list`. It  will be populated and
+ * sorted by `find_unique_prefixes()`.
+ */
+struct prefix_item_list {
+	struct string_list items;
+	struct string_list sorted;
+	int *selected; /* for multi-selections */
+	size_t min_length, max_length;
+};
+#define PREFIX_ITEM_LIST_INIT \
+	{ STRING_LIST_INIT_DUP, STRING_LIST_INIT_NODUP, NULL, 1, 4 }
+
+static void prefix_item_list_clear(struct prefix_item_list *list)
+{
+	string_list_clear(&list->items, 1);
+	string_list_clear(&list->sorted, 0);
+	FREE_AND_NULL(list->selected);
+}
+
+static void extend_prefix_length(struct string_list_item *p,
+				 const char *other_string, size_t max_length)
+{
+	size_t *len = p->util;
+
+	if (!*len || memcmp(p->string, other_string, *len))
+		return;
+
+	for (;;) {
+		char c = p->string[*len];
+
+		/*
+		 * Is `p` a strict prefix of `other`? Or have we exhausted the
+		 * maximal length of the prefix? Or is the current character a
+		 * multi-byte UTF-8 one? If so, there is no valid, unique
+		 * prefix.
+		 */
+		if (!c || ++*len > max_length || !isascii(c)) {
+			*len = 0;
+			break;
+		}
+
+		if (c != other_string[*len - 1])
+			break;
+	}
+}
+
+static void find_unique_prefixes(struct prefix_item_list *list)
+{
+	size_t i;
+
+	if (list->sorted.nr == list->items.nr)
+		return;
+
+	string_list_clear(&list->sorted, 0);
+	/* Avoid reallocating incrementally */
+	list->sorted.items = xmalloc(st_mult(sizeof(*list->sorted.items),
+					     list->items.nr));
+	list->sorted.nr = list->sorted.alloc = list->items.nr;
+
+	for (i = 0; i < list->items.nr; i++) {
+		list->sorted.items[i].string = list->items.items[i].string;
+		list->sorted.items[i].util = list->items.items + i;
+	}
+
+	string_list_sort(&list->sorted);
+
+	for (i = 0; i < list->sorted.nr; i++) {
+		struct string_list_item *sorted_item = list->sorted.items + i;
+		struct string_list_item *item = sorted_item->util;
+		size_t *len = item->util;
+
+		*len = 0;
+		while (*len < list->min_length) {
+			char c = item->string[(*len)++];
+
+			if (!c || !isascii(c)) {
+				*len = 0;
+				break;
+			}
+		}
+
+		if (i > 0)
+			extend_prefix_length(item, sorted_item[-1].string,
+					     list->max_length);
+		if (i + 1 < list->sorted.nr)
+			extend_prefix_length(item, sorted_item[1].string,
+					     list->max_length);
+	}
+}
+
+static ssize_t find_unique(const char *string, struct prefix_item_list *list)
+{
+	int index = string_list_find_insert_index(&list->sorted, string, 1);
+	struct string_list_item *item;
+
+	if (list->items.nr != list->sorted.nr)
+		BUG("prefix_item_list in inconsistent state (%"PRIuMAX
+		    " vs %"PRIuMAX")",
+		    (uintmax_t)list->items.nr, (uintmax_t)list->sorted.nr);
+
+	if (index < 0)
+		item = list->sorted.items[-1 - index].util;
+	else if (index > 0 &&
+		 starts_with(list->sorted.items[index - 1].string, string))
+		return -1;
+	else if (index + 1 < list->sorted.nr &&
+		 starts_with(list->sorted.items[index + 1].string, string))
+		return -1;
+	else if (index < list->sorted.nr)
+		item = list->sorted.items[index].util;
+	else
+		return -1;
+	return item - list->items.items;
+}
+
+struct list_options {
+	int columns;
+	const char *header;
+	void (*print_item)(int i, int selected, struct string_list_item *item,
+			   void *print_item_data);
+	void *print_item_data;
+};
+
+static void list(struct add_i_state *s, struct string_list *list, int *selected,
+		 struct list_options *opts)
+{
+	int i, last_lf = 0;
+
+	if (!list->nr)
+		return;
+
+	if (opts->header)
+		color_fprintf_ln(stdout, s->header_color,
+				 "%s", opts->header);
+
+	for (i = 0; i < list->nr; i++) {
+		opts->print_item(i, selected ? selected[i] : 0, list->items + i,
+				 opts->print_item_data);
+
+		if ((opts->columns) && ((i + 1) % (opts->columns))) {
+			putchar('\t');
+			last_lf = 0;
+		}
+		else {
+			putchar('\n');
+			last_lf = 1;
+		}
+	}
+
+	if (!last_lf)
+		putchar('\n');
+}
+struct list_and_choose_options {
+	struct list_options list_opts;
+
+	const char *prompt;
+	enum {
+		SINGLETON = (1<<0),
+		IMMEDIATE = (1<<1),
+	} flags;
+	void (*print_help)(struct add_i_state *s);
+};
+
+#define LIST_AND_CHOOSE_ERROR (-1)
+#define LIST_AND_CHOOSE_QUIT  (-2)
+
+/*
+ * Returns the selected index in singleton mode, the number of selected items
+ * otherwise.
+ *
+ * If an error occurred, returns `LIST_AND_CHOOSE_ERROR`. Upon EOF,
+ * `LIST_AND_CHOOSE_QUIT` is returned.
+ */
+static ssize_t list_and_choose(struct add_i_state *s,
+			       struct prefix_item_list *items,
+			       struct list_and_choose_options *opts)
+{
+	int singleton = opts->flags & SINGLETON;
+	int immediate = opts->flags & IMMEDIATE;
+
+	struct strbuf input = STRBUF_INIT;
+	ssize_t res = singleton ? LIST_AND_CHOOSE_ERROR : 0;
+
+	if (!singleton) {
+		free(items->selected);
+		CALLOC_ARRAY(items->selected, items->items.nr);
+	}
+
+	if (singleton && !immediate)
+		BUG("singleton requires immediate");
+
+	find_unique_prefixes(items);
+
+	for (;;) {
+		char *p;
+
+		strbuf_reset(&input);
+
+		list(s, &items->items, items->selected, &opts->list_opts);
+
+		color_fprintf(stdout, s->prompt_color, "%s", opts->prompt);
+		fputs(singleton ? "> " : ">> ", stdout);
+		fflush(stdout);
+
+		if (strbuf_getline(&input, stdin) == EOF) {
+			putchar('\n');
+			if (immediate)
+				res = LIST_AND_CHOOSE_QUIT;
+			break;
+		}
+		strbuf_trim(&input);
+
+		if (!input.len)
+			break;
+
+		if (!strcmp(input.buf, "?")) {
+			opts->print_help(s);
+			continue;
+		}
+
+		p = input.buf;
+		for (;;) {
+			size_t sep = strcspn(p, " \t\r\n,");
+			int choose = 1;
+			/* `from` is inclusive, `to` is exclusive */
+			ssize_t from = -1, to = -1;
+
+			if (!sep) {
+				if (!*p)
+					break;
+				p++;
+				continue;
+			}
+
+			/* Input that begins with '-'; de-select */
+			if (*p == '-') {
+				choose = 0;
+				p++;
+				sep--;
+			}
+
+			if (sep == 1 && *p == '*') {
+				from = 0;
+				to = items->items.nr;
+			} else if (isdigit(*p)) {
+				char *endp;
+				/*
+				 * A range can be specified like 5-7 or 5-.
+				 *
+				 * Note: `from` is 0-based while the user input
+				 * is 1-based, hence we have to decrement by
+				 * one. We do not have to decrement `to` even
+				 * if it is 0-based because it is an exclusive
+				 * boundary.
+				 */
+				from = strtoul(p, &endp, 10) - 1;
+				if (endp == p + sep)
+					to = from + 1;
+				else if (*endp == '-') {
+					if (isdigit(*(++endp)))
+						to = strtoul(endp, &endp, 10);
+					else
+						to = items->items.nr;
+					/* extra characters after the range? */
+					if (endp != p + sep)
+						from = -1;
+				}
+			}
+
+			if (p[sep])
+				p[sep++] = '\0';
+			if (from < 0) {
+				from = find_unique(p, items);
+				if (from >= 0)
+					to = from + 1;
+			}
+
+			if (from < 0 || from >= items->items.nr ||
+			    (singleton && from + 1 != to)) {
+				color_fprintf_ln(stdout, s->error_color,
+						 _("Huh (%s)?"), p);
+				break;
+			} else if (singleton) {
+				res = from;
+				break;
+			}
+
+			if (to > items->items.nr)
+				to = items->items.nr;
+
+			for (; from < to; from++)
+				if (items->selected[from] != choose) {
+					items->selected[from] = choose;
+					res += choose ? +1 : -1;
+				}
+
+			p += sep;
+		}
+
+		if ((immediate && res != LIST_AND_CHOOSE_ERROR) ||
+		    !strcmp(input.buf, "*"))
+			break;
+	}
+
+	strbuf_release(&input);
+	return res;
+}
+
+struct adddel {
+	uintmax_t add, del;
+	unsigned seen:1, unmerged:1, binary:1;
+};
+
+struct file_item {
+	size_t prefix_length;
+	struct adddel index, worktree;
+};
+
+static void add_file_item(struct string_list *files, const char *name)
+{
+	struct file_item *item = xcalloc(sizeof(*item), 1);
+
+	string_list_append(files, name)->util = item;
+}
+
+struct pathname_entry {
+	struct hashmap_entry ent;
+	const char *name;
+	struct file_item *item;
+};
+
+static int pathname_entry_cmp(const void *unused_cmp_data,
+			      const struct hashmap_entry *he1,
+			      const struct hashmap_entry *he2,
+			      const void *name)
+{
+	const struct pathname_entry *e1 =
+		container_of(he1, const struct pathname_entry, ent);
+	const struct pathname_entry *e2 =
+		container_of(he2, const struct pathname_entry, ent);
+
+	return strcmp(e1->name, name ? (const char *)name : e2->name);
+}
+
+struct collection_status {
+	enum { FROM_WORKTREE = 0, FROM_INDEX = 1 } mode;
+
+	const char *reference;
+
+	unsigned skip_unseen:1;
+	size_t unmerged_count, binary_count;
+	struct string_list *files;
+	struct hashmap file_map;
+};
+
+static void collect_changes_cb(struct diff_queue_struct *q,
+			       struct diff_options *options,
+			       void *data)
+{
+	struct collection_status *s = data;
+	struct diffstat_t stat = { 0 };
+	int i;
+
+	if (!q->nr)
+		return;
+
+	compute_diffstat(options, &stat, q);
+
+	for (i = 0; i < stat.nr; i++) {
+		const char *name = stat.files[i]->name;
+		int hash = strhash(name);
+		struct pathname_entry *entry;
+		struct file_item *file_item;
+		struct adddel *adddel, *other_adddel;
+
+		entry = hashmap_get_entry_from_hash(&s->file_map, hash, name,
+						    struct pathname_entry, ent);
+		if (!entry) {
+			if (s->skip_unseen)
+				continue;
+
+			add_file_item(s->files, name);
+
+			entry = xcalloc(sizeof(*entry), 1);
+			hashmap_entry_init(&entry->ent, hash);
+			entry->name = s->files->items[s->files->nr - 1].string;
+			entry->item = s->files->items[s->files->nr - 1].util;
+			hashmap_add(&s->file_map, &entry->ent);
+		}
+
+		file_item = entry->item;
+		adddel = s->mode == FROM_INDEX ?
+			&file_item->index : &file_item->worktree;
+		other_adddel = s->mode == FROM_INDEX ?
+			&file_item->worktree : &file_item->index;
+		adddel->seen = 1;
+		adddel->add = stat.files[i]->added;
+		adddel->del = stat.files[i]->deleted;
+		if (stat.files[i]->is_binary) {
+			if (!other_adddel->binary)
+				s->binary_count++;
+			adddel->binary = 1;
+		}
+		if (stat.files[i]->is_unmerged) {
+			if (!other_adddel->unmerged)
+				s->unmerged_count++;
+			adddel->unmerged = 1;
+		}
+	}
+	free_diffstat_info(&stat);
+}
+
+enum modified_files_filter {
+	NO_FILTER = 0,
+	WORKTREE_ONLY = 1,
+	INDEX_ONLY = 2,
+};
+
+static int get_modified_files(struct repository *r,
+			      enum modified_files_filter filter,
+			      struct prefix_item_list *files,
+			      const struct pathspec *ps,
+			      size_t *unmerged_count,
+			      size_t *binary_count)
+{
+	struct object_id head_oid;
+	int is_initial = !resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
+					     &head_oid, NULL);
+	struct collection_status s = { 0 };
+	int i;
+
+	if (discard_index(r->index) < 0 ||
+	    repo_read_index_preload(r, ps, 0) < 0)
+		return error(_("could not read index"));
+
+	prefix_item_list_clear(files);
+	s.files = &files->items;
+	hashmap_init(&s.file_map, pathname_entry_cmp, NULL, 0);
+
+	for (i = 0; i < 2; i++) {
+		struct rev_info rev;
+		struct setup_revision_opt opt = { 0 };
+
+		if (filter == INDEX_ONLY)
+			s.mode = (i == 0) ? FROM_INDEX : FROM_WORKTREE;
+		else
+			s.mode = (i == 0) ? FROM_WORKTREE : FROM_INDEX;
+		s.skip_unseen = filter && i;
+
+		opt.def = is_initial ?
+			empty_tree_oid_hex() : oid_to_hex(&head_oid);
+
+		init_revisions(&rev, NULL);
+		setup_revisions(0, NULL, &rev, &opt);
+
+		rev.diffopt.output_format = DIFF_FORMAT_CALLBACK;
+		rev.diffopt.format_callback = collect_changes_cb;
+		rev.diffopt.format_callback_data = &s;
+
+		if (ps)
+			copy_pathspec(&rev.prune_data, ps);
+
+		if (s.mode == FROM_INDEX)
+			run_diff_index(&rev, 1);
+		else {
+			rev.diffopt.flags.ignore_dirty_submodules = 1;
+			run_diff_files(&rev, 0);
+		}
+
+		if (ps)
+			clear_pathspec(&rev.prune_data);
+	}
+	hashmap_free_entries(&s.file_map, struct pathname_entry, ent);
+	if (unmerged_count)
+		*unmerged_count = s.unmerged_count;
+	if (binary_count)
+		*binary_count = s.binary_count;
+
+	/* While the diffs are ordered already, we ran *two* diffs... */
+	string_list_sort(&files->items);
+
+	return 0;
+}
+
+static void render_adddel(struct strbuf *buf,
+				struct adddel *ad, const char *no_changes)
+{
+	if (ad->binary)
+		strbuf_addstr(buf, _("binary"));
+	else if (ad->seen)
+		strbuf_addf(buf, "+%"PRIuMAX"/-%"PRIuMAX,
+			    (uintmax_t)ad->add, (uintmax_t)ad->del);
+	else
+		strbuf_addstr(buf, no_changes);
+}
+
+/* filters out prefixes which have special meaning to list_and_choose() */
+static int is_valid_prefix(const char *prefix, size_t prefix_len)
+{
+	return prefix_len && prefix &&
+		/*
+		 * We expect `prefix` to be NUL terminated, therefore this
+		 * `strcspn()` call is okay, even if it might do much more
+		 * work than strictly necessary.
+		 */
+		strcspn(prefix, " \t\r\n,") >= prefix_len &&	/* separators */
+		*prefix != '-' &&				/* deselection */
+		!isdigit(*prefix) &&				/* selection */
+		(prefix_len != 1 ||
+		 (*prefix != '*' &&				/* "all" wildcard */
+		  *prefix != '?'));				/* prompt help */
+}
+
+struct print_file_item_data {
+	const char *modified_fmt, *color, *reset;
+	struct strbuf buf, name, index, worktree;
+	unsigned only_names:1;
+};
+
+static void print_file_item(int i, int selected, struct string_list_item *item,
+			    void *print_file_item_data)
+{
+	struct file_item *c = item->util;
+	struct print_file_item_data *d = print_file_item_data;
+	const char *highlighted = NULL;
+
+	strbuf_reset(&d->index);
+	strbuf_reset(&d->worktree);
+	strbuf_reset(&d->buf);
+
+	/* Format the item with the prefix highlighted. */
+	if (c->prefix_length > 0 &&
+	    is_valid_prefix(item->string, c->prefix_length)) {
+		strbuf_reset(&d->name);
+		strbuf_addf(&d->name, "%s%.*s%s%s", d->color,
+			    (int)c->prefix_length, item->string, d->reset,
+			    item->string + c->prefix_length);
+		highlighted = d->name.buf;
+	}
+
+	if (d->only_names) {
+		printf("%c%2d: %s", selected ? '*' : ' ', i + 1,
+		       highlighted ? highlighted : item->string);
+		return;
+	}
+
+	render_adddel(&d->worktree, &c->worktree, _("nothing"));
+	render_adddel(&d->index, &c->index, _("unchanged"));
+
+	strbuf_addf(&d->buf, d->modified_fmt, d->index.buf, d->worktree.buf,
+		    highlighted ? highlighted : item->string);
+
+	printf("%c%2d: %s", selected ? '*' : ' ', i + 1, d->buf.buf);
+}
+
+static int run_status(struct add_i_state *s, const struct pathspec *ps,
+		      struct prefix_item_list *files,
+		      struct list_and_choose_options *opts)
+{
+	if (get_modified_files(s->r, NO_FILTER, files, ps, NULL, NULL) < 0)
+		return -1;
+
+	list(s, &files->items, NULL, &opts->list_opts);
+	putchar('\n');
+
+	return 0;
+}
+
+static int run_update(struct add_i_state *s, const struct pathspec *ps,
+		      struct prefix_item_list *files,
+		      struct list_and_choose_options *opts)
+{
+	int res = 0, fd;
+	size_t count, i;
+	struct lock_file index_lock;
+
+	if (get_modified_files(s->r, WORKTREE_ONLY, files, ps, NULL, NULL) < 0)
+		return -1;
+
+	if (!files->items.nr) {
+		putchar('\n');
+		return 0;
+	}
+
+	opts->prompt = N_("Update");
+	count = list_and_choose(s, files, opts);
+	if (count <= 0) {
+		putchar('\n');
+		return 0;
+	}
+
+	fd = repo_hold_locked_index(s->r, &index_lock, LOCK_REPORT_ON_ERROR);
+	if (fd < 0) {
+		putchar('\n');
+		return -1;
+	}
+
+	for (i = 0; i < files->items.nr; i++) {
+		const char *name = files->items.items[i].string;
+		if (files->selected[i] &&
+		    add_file_to_index(s->r->index, name, 0) < 0) {
+			res = error(_("could not stage '%s'"), name);
+			break;
+		}
+	}
+
+	if (!res && write_locked_index(s->r->index, &index_lock, COMMIT_LOCK) < 0)
+		res = error(_("could not write index"));
+
+	if (!res)
+		printf(Q_("updated %d path\n",
+			  "updated %d paths\n", count), (int)count);
+
+	putchar('\n');
+	return res;
+}
+
+static void revert_from_diff(struct diff_queue_struct *q,
+			     struct diff_options *opt, void *data)
+{
+	int i, add_flags = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
+
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filespec *one = q->queue[i]->one;
+		struct cache_entry *ce;
+
+		if (!(one->mode && !is_null_oid(&one->oid))) {
+			remove_file_from_index(opt->repo->index, one->path);
+			printf(_("note: %s is untracked now.\n"), one->path);
+		} else {
+			ce = make_cache_entry(opt->repo->index, one->mode,
+					      &one->oid, one->path, 0, 0);
+			if (!ce)
+				die(_("make_cache_entry failed for path '%s'"),
+				    one->path);
+			add_index_entry(opt->repo->index, ce, add_flags);
+		}
+	}
+}
+
+static int run_revert(struct add_i_state *s, const struct pathspec *ps,
+		      struct prefix_item_list *files,
+		      struct list_and_choose_options *opts)
+{
+	int res = 0, fd;
+	size_t count, i, j;
+
+	struct object_id oid;
+	int is_initial = !resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &oid,
+					     NULL);
+	struct lock_file index_lock;
+	const char **paths;
+	struct tree *tree;
+	struct diff_options diffopt = { NULL };
+
+	if (get_modified_files(s->r, INDEX_ONLY, files, ps, NULL, NULL) < 0)
+		return -1;
+
+	if (!files->items.nr) {
+		putchar('\n');
+		return 0;
+	}
+
+	opts->prompt = N_("Revert");
+	count = list_and_choose(s, files, opts);
+	if (count <= 0)
+		goto finish_revert;
+
+	fd = repo_hold_locked_index(s->r, &index_lock, LOCK_REPORT_ON_ERROR);
+	if (fd < 0) {
+		res = -1;
+		goto finish_revert;
+	}
+
+	if (is_initial)
+		oidcpy(&oid, s->r->hash_algo->empty_tree);
+	else {
+		tree = parse_tree_indirect(&oid);
+		if (!tree) {
+			res = error(_("Could not parse HEAD^{tree}"));
+			goto finish_revert;
+		}
+		oidcpy(&oid, &tree->object.oid);
+	}
+
+	ALLOC_ARRAY(paths, count + 1);
+	for (i = j = 0; i < files->items.nr; i++)
+		if (files->selected[i])
+			paths[j++] = files->items.items[i].string;
+	paths[j] = NULL;
+
+	parse_pathspec(&diffopt.pathspec, 0,
+		       PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH,
+		       NULL, paths);
+
+	diffopt.output_format = DIFF_FORMAT_CALLBACK;
+	diffopt.format_callback = revert_from_diff;
+	diffopt.flags.override_submodule_config = 1;
+	diffopt.repo = s->r;
+
+	if (do_diff_cache(&oid, &diffopt))
+		res = -1;
+	else {
+		diffcore_std(&diffopt);
+		diff_flush(&diffopt);
+	}
+	free(paths);
+	clear_pathspec(&diffopt.pathspec);
+
+	if (!res && write_locked_index(s->r->index, &index_lock,
+				       COMMIT_LOCK) < 0)
+		res = -1;
+	else
+		res = repo_refresh_and_write_index(s->r, REFRESH_QUIET, 0, 1,
+						   NULL, NULL, NULL);
+
+	if (!res)
+		printf(Q_("reverted %d path\n",
+			  "reverted %d paths\n", count), (int)count);
+
+finish_revert:
+	putchar('\n');
+	return res;
+}
+
+static int get_untracked_files(struct repository *r,
+			       struct prefix_item_list *files,
+			       const struct pathspec *ps)
+{
+	struct dir_struct dir = { 0 };
+	size_t i;
+	struct strbuf buf = STRBUF_INIT;
+
+	if (repo_read_index(r) < 0)
+		return error(_("could not read index"));
+
+	prefix_item_list_clear(files);
+	setup_standard_excludes(&dir);
+	add_pattern_list(&dir, EXC_CMDL, "--exclude option");
+	fill_directory(&dir, r->index, ps);
+
+	for (i = 0; i < dir.nr; i++) {
+		struct dir_entry *ent = dir.entries[i];
+
+		if (index_name_is_other(r->index, ent->name, ent->len)) {
+			strbuf_reset(&buf);
+			strbuf_add(&buf, ent->name, ent->len);
+			add_file_item(&files->items, buf.buf);
+		}
+	}
+
+	strbuf_release(&buf);
+	return 0;
+}
+
+static int run_add_untracked(struct add_i_state *s, const struct pathspec *ps,
+		      struct prefix_item_list *files,
+		      struct list_and_choose_options *opts)
+{
+	struct print_file_item_data *d = opts->list_opts.print_item_data;
+	int res = 0, fd;
+	size_t count, i;
+	struct lock_file index_lock;
+
+	if (get_untracked_files(s->r, files, ps) < 0)
+		return -1;
+
+	if (!files->items.nr) {
+		printf(_("No untracked files.\n"));
+		goto finish_add_untracked;
+	}
+
+	opts->prompt = N_("Add untracked");
+	d->only_names = 1;
+	count = list_and_choose(s, files, opts);
+	d->only_names = 0;
+	if (count <= 0)
+		goto finish_add_untracked;
+
+	fd = repo_hold_locked_index(s->r, &index_lock, LOCK_REPORT_ON_ERROR);
+	if (fd < 0) {
+		res = -1;
+		goto finish_add_untracked;
+	}
+
+	for (i = 0; i < files->items.nr; i++) {
+		const char *name = files->items.items[i].string;
+		if (files->selected[i] &&
+		    add_file_to_index(s->r->index, name, 0) < 0) {
+			res = error(_("could not stage '%s'"), name);
+			break;
+		}
+	}
+
+	if (!res &&
+	    write_locked_index(s->r->index, &index_lock, COMMIT_LOCK) < 0)
+		res = error(_("could not write index"));
+
+	if (!res)
+		printf(Q_("added %d path\n",
+			  "added %d paths\n", count), (int)count);
+
+finish_add_untracked:
+	putchar('\n');
+	return res;
+}
+
+static int run_patch(struct add_i_state *s, const struct pathspec *ps,
+		     struct prefix_item_list *files,
+		     struct list_and_choose_options *opts)
+{
+	int res = 0;
+	ssize_t count, i, j;
+	size_t unmerged_count = 0, binary_count = 0;
+
+	if (get_modified_files(s->r, WORKTREE_ONLY, files, ps,
+			       &unmerged_count, &binary_count) < 0)
+		return -1;
+
+	if (unmerged_count || binary_count) {
+		for (i = j = 0; i < files->items.nr; i++) {
+			struct file_item *item = files->items.items[i].util;
+
+			if (item->index.binary || item->worktree.binary) {
+				free(item);
+				free(files->items.items[i].string);
+			} else if (item->index.unmerged ||
+				 item->worktree.unmerged) {
+				color_fprintf_ln(stderr, s->error_color,
+						 _("ignoring unmerged: %s"),
+						 files->items.items[i].string);
+				free(item);
+				free(files->items.items[i].string);
+			} else
+				files->items.items[j++] = files->items.items[i];
+		}
+		files->items.nr = j;
+	}
+
+	if (!files->items.nr) {
+		if (binary_count)
+			fprintf(stderr, _("Only binary files changed.\n"));
+		else
+			fprintf(stderr, _("No changes.\n"));
+		return 0;
+	}
+
+	opts->prompt = N_("Patch update");
+	count = list_and_choose(s, files, opts);
+	if (count > 0) {
+		struct argv_array args = ARGV_ARRAY_INIT;
+		struct pathspec ps_selected = { 0 };
+
+		for (i = 0; i < files->items.nr; i++)
+			if (files->selected[i])
+				argv_array_push(&args,
+						files->items.items[i].string);
+		parse_pathspec(&ps_selected,
+			       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
+			       PATHSPEC_LITERAL_PATH, "", args.argv);
+		res = run_add_p(s->r, ADD_P_ADD, NULL, &ps_selected);
+		argv_array_clear(&args);
+		clear_pathspec(&ps_selected);
+	}
+
+	return res;
+}
+
+static int run_diff(struct add_i_state *s, const struct pathspec *ps,
+		    struct prefix_item_list *files,
+		    struct list_and_choose_options *opts)
+{
+	int res = 0;
+	ssize_t count, i;
+
+	struct object_id oid;
+	int is_initial = !resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &oid,
+					     NULL);
+	if (get_modified_files(s->r, INDEX_ONLY, files, ps, NULL, NULL) < 0)
+		return -1;
+
+	if (!files->items.nr) {
+		putchar('\n');
+		return 0;
+	}
+
+	opts->prompt = N_("Review diff");
+	opts->flags = IMMEDIATE;
+	count = list_and_choose(s, files, opts);
+	opts->flags = 0;
+	if (count > 0) {
+		struct argv_array args = ARGV_ARRAY_INIT;
+
+		argv_array_pushl(&args, "git", "diff", "-p", "--cached",
+				 oid_to_hex(!is_initial ? &oid :
+					    s->r->hash_algo->empty_tree),
+				 "--", NULL);
+		for (i = 0; i < files->items.nr; i++)
+			if (files->selected[i])
+				argv_array_push(&args,
+						files->items.items[i].string);
+		res = run_command_v_opt(args.argv, 0);
+		argv_array_clear(&args);
+	}
+
+	putchar('\n');
+	return res;
+}
+
+static int run_help(struct add_i_state *s, const struct pathspec *unused_ps,
+		    struct prefix_item_list *unused_files,
+		    struct list_and_choose_options *unused_opts)
+{
+	color_fprintf_ln(stdout, s->help_color, "status        - %s",
+			 _("show paths with changes"));
+	color_fprintf_ln(stdout, s->help_color, "update        - %s",
+			 _("add working tree state to the staged set of changes"));
+	color_fprintf_ln(stdout, s->help_color, "revert        - %s",
+			 _("revert staged set of changes back to the HEAD version"));
+	color_fprintf_ln(stdout, s->help_color, "patch         - %s",
+			 _("pick hunks and update selectively"));
+	color_fprintf_ln(stdout, s->help_color, "diff          - %s",
+			 _("view diff between HEAD and index"));
+	color_fprintf_ln(stdout, s->help_color, "add untracked - %s",
+			 _("add contents of untracked files to the staged set of changes"));
+
+	return 0;
+}
+
+static void choose_prompt_help(struct add_i_state *s)
+{
+	color_fprintf_ln(stdout, s->help_color, "%s",
+			 _("Prompt help:"));
+	color_fprintf_ln(stdout, s->help_color, "1          - %s",
+			 _("select a single item"));
+	color_fprintf_ln(stdout, s->help_color, "3-5        - %s",
+			 _("select a range of items"));
+	color_fprintf_ln(stdout, s->help_color, "2-3,6-9    - %s",
+			 _("select multiple ranges"));
+	color_fprintf_ln(stdout, s->help_color, "foo        - %s",
+			 _("select item based on unique prefix"));
+	color_fprintf_ln(stdout, s->help_color, "-...       - %s",
+			 _("unselect specified items"));
+	color_fprintf_ln(stdout, s->help_color, "*          - %s",
+			 _("choose all items"));
+	color_fprintf_ln(stdout, s->help_color, "           - %s",
+			 _("(empty) finish selecting"));
+}
+
+typedef int (*command_t)(struct add_i_state *s, const struct pathspec *ps,
+			 struct prefix_item_list *files,
+			 struct list_and_choose_options *opts);
+
+struct command_item {
+	size_t prefix_length;
+	command_t command;
+};
+
+struct print_command_item_data {
+	const char *color, *reset;
+};
+
+static void print_command_item(int i, int selected,
+			       struct string_list_item *item,
+			       void *print_command_item_data)
+{
+	struct print_command_item_data *d = print_command_item_data;
+	struct command_item *util = item->util;
+
+	if (!util->prefix_length ||
+	    !is_valid_prefix(item->string, util->prefix_length))
+		printf(" %2d: %s", i + 1, item->string);
+	else
+		printf(" %2d: %s%.*s%s%s", i + 1,
+		       d->color, (int)util->prefix_length, item->string,
+		       d->reset, item->string + util->prefix_length);
+}
+
+static void command_prompt_help(struct add_i_state *s)
+{
+	const char *help_color = s->help_color;
+	color_fprintf_ln(stdout, help_color, "%s", _("Prompt help:"));
+	color_fprintf_ln(stdout, help_color, "1          - %s",
+			 _("select a numbered item"));
+	color_fprintf_ln(stdout, help_color, "foo        - %s",
+			 _("select item based on unique prefix"));
+	color_fprintf_ln(stdout, help_color, "           - %s",
+			 _("(empty) select nothing"));
+}
+
+int run_add_i(struct repository *r, const struct pathspec *ps)
+{
+	struct add_i_state s = { NULL };
+	struct print_command_item_data data = { "[", "]" };
+	struct list_and_choose_options main_loop_opts = {
+		{ 4, N_("*** Commands ***"), print_command_item, &data },
+		N_("What now"), SINGLETON | IMMEDIATE, command_prompt_help
+	};
+	struct {
+		const char *string;
+		command_t command;
+	} command_list[] = {
+		{ "status", run_status },
+		{ "update", run_update },
+		{ "revert", run_revert },
+		{ "add untracked", run_add_untracked },
+		{ "patch", run_patch },
+		{ "diff", run_diff },
+		{ "quit", NULL },
+		{ "help", run_help },
+	};
+	struct prefix_item_list commands = PREFIX_ITEM_LIST_INIT;
+
+	struct print_file_item_data print_file_item_data = {
+		"%12s %12s %s", NULL, NULL,
+		STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
+	};
+	struct list_and_choose_options opts = {
+		{ 0, NULL, print_file_item, &print_file_item_data },
+		NULL, 0, choose_prompt_help
+	};
+	struct strbuf header = STRBUF_INIT;
+	struct prefix_item_list files = PREFIX_ITEM_LIST_INIT;
+	ssize_t i;
+	int res = 0;
+
+	for (i = 0; i < ARRAY_SIZE(command_list); i++) {
+		struct command_item *util = xcalloc(sizeof(*util), 1);
+		util->command = command_list[i].command;
+		string_list_append(&commands.items, command_list[i].string)
+			->util = util;
+	}
+
+	init_add_i_state(&s, r);
+
+	/*
+	 * When color was asked for, use the prompt color for
+	 * highlighting, otherwise use square brackets.
+	 */
+	if (s.use_color) {
+		data.color = s.prompt_color;
+		data.reset = s.reset_color;
+	}
+	print_file_item_data.color = data.color;
+	print_file_item_data.reset = data.reset;
+
+	strbuf_addstr(&header, "      ");
+	strbuf_addf(&header, print_file_item_data.modified_fmt,
+		    _("staged"), _("unstaged"), _("path"));
+	opts.list_opts.header = header.buf;
+
+	if (discard_index(r->index) < 0 ||
+	    repo_read_index(r) < 0 ||
+	    repo_refresh_and_write_index(r, REFRESH_QUIET, 0, 1,
+					 NULL, NULL, NULL) < 0)
+		warning(_("could not refresh index"));
+
+	res = run_status(&s, ps, &files, &opts);
+
+	for (;;) {
+		struct command_item *util;
+
+		i = list_and_choose(&s, &commands, &main_loop_opts);
+		if (i < 0 || i >= commands.items.nr)
+			util = NULL;
+		else
+			util = commands.items.items[i].util;
+
+		if (i == LIST_AND_CHOOSE_QUIT || (util && !util->command)) {
+			printf(_("Bye.\n"));
+			res = 0;
+			break;
+		}
+
+		if (util)
+			res = util->command(&s, ps, &files, &opts);
+	}
+
+	prefix_item_list_clear(&files);
+	strbuf_release(&print_file_item_data.buf);
+	strbuf_release(&print_file_item_data.name);
+	strbuf_release(&print_file_item_data.index);
+	strbuf_release(&print_file_item_data.worktree);
+	strbuf_release(&header);
+	prefix_item_list_clear(&commands);
+	clear_add_i_state(&s);
+
+	return res;
+}