merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

1 files changed, 1239 insertions, 0 deletions

diff --git a/third_party/git/builtin/update-index.c b/third_party/git/builtin/update-index.c
new file mode 100644
index 0000000000..dff2f4b837
--- /dev/null
+++ b/third_party/git/builtin/update-index.c
@@ -0,0 +1,1239 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ */
+#define USE_THE_INDEX_COMPATIBILITY_MACROS
+#include "cache.h"
+#include "config.h"
+#include "lockfile.h"
+#include "quote.h"
+#include "cache-tree.h"
+#include "tree-walk.h"
+#include "builtin.h"
+#include "refs.h"
+#include "resolve-undo.h"
+#include "parse-options.h"
+#include "pathspec.h"
+#include "dir.h"
+#include "split-index.h"
+#include "fsmonitor.h"
+
+/*
+ * Default to not allowing changes to the list of files. The
+ * tool doesn't actually care, but this makes it harder to add
+ * files to the revision control by mistake by doing something
+ * like "git update-index *" and suddenly having all the object
+ * files be revision controlled.
+ */
+static int allow_add;
+static int allow_remove;
+static int allow_replace;
+static int info_only;
+static int force_remove;
+static int verbose;
+static int mark_valid_only;
+static int mark_skip_worktree_only;
+static int mark_fsmonitor_only;
+#define MARK_FLAG 1
+#define UNMARK_FLAG 2
+static struct strbuf mtime_dir = STRBUF_INIT;
+
+/* Untracked cache mode */
+enum uc_mode {
+	UC_UNSPECIFIED = -1,
+	UC_DISABLE = 0,
+	UC_ENABLE,
+	UC_TEST,
+	UC_FORCE
+};
+
+__attribute__((format (printf, 1, 2)))
+static void report(const char *fmt, ...)
+{
+	va_list vp;
+
+	if (!verbose)
+		return;
+
+	va_start(vp, fmt);
+	vprintf(fmt, vp);
+	putchar('\n');
+	va_end(vp);
+}
+
+static void remove_test_directory(void)
+{
+	if (mtime_dir.len)
+		remove_dir_recursively(&mtime_dir, 0);
+}
+
+static const char *get_mtime_path(const char *path)
+{
+	static struct strbuf sb = STRBUF_INIT;
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s/%s", mtime_dir.buf, path);
+	return sb.buf;
+}
+
+static void xmkdir(const char *path)
+{
+	path = get_mtime_path(path);
+	if (mkdir(path, 0700))
+		die_errno(_("failed to create directory %s"), path);
+}
+
+static int xstat_mtime_dir(struct stat *st)
+{
+	if (stat(mtime_dir.buf, st))
+		die_errno(_("failed to stat %s"), mtime_dir.buf);
+	return 0;
+}
+
+static int create_file(const char *path)
+{
+	int fd;
+	path = get_mtime_path(path);
+	fd = open(path, O_CREAT | O_RDWR, 0644);
+	if (fd < 0)
+		die_errno(_("failed to create file %s"), path);
+	return fd;
+}
+
+static void xunlink(const char *path)
+{
+	path = get_mtime_path(path);
+	if (unlink(path))
+		die_errno(_("failed to delete file %s"), path);
+}
+
+static void xrmdir(const char *path)
+{
+	path = get_mtime_path(path);
+	if (rmdir(path))
+		die_errno(_("failed to delete directory %s"), path);
+}
+
+static void avoid_racy(void)
+{
+	/*
+	 * not use if we could usleep(10) if USE_NSEC is defined. The
+	 * field nsec could be there, but the OS could choose to
+	 * ignore it?
+	 */
+	sleep(1);
+}
+
+static int test_if_untracked_cache_is_supported(void)
+{
+	struct stat st;
+	struct stat_data base;
+	int fd, ret = 0;
+	char *cwd;
+
+	strbuf_addstr(&mtime_dir, "mtime-test-XXXXXX");
+	if (!mkdtemp(mtime_dir.buf))
+		die_errno("Could not make temporary directory");
+
+	cwd = xgetcwd();
+	fprintf(stderr, _("Testing mtime in '%s' "), cwd);
+	free(cwd);
+
+	atexit(remove_test_directory);
+	xstat_mtime_dir(&st);
+	fill_stat_data(&base, &st);
+	fputc('.', stderr);
+
+	avoid_racy();
+	fd = create_file("newfile");
+	xstat_mtime_dir(&st);
+	if (!match_stat_data(&base, &st)) {
+		close(fd);
+		fputc('\n', stderr);
+		fprintf_ln(stderr,_("directory stat info does not "
+				    "change after adding a new file"));
+		goto done;
+	}
+	fill_stat_data(&base, &st);
+	fputc('.', stderr);
+
+	avoid_racy();
+	xmkdir("new-dir");
+	xstat_mtime_dir(&st);
+	if (!match_stat_data(&base, &st)) {
+		close(fd);
+		fputc('\n', stderr);
+		fprintf_ln(stderr, _("directory stat info does not change "
+				     "after adding a new directory"));
+		goto done;
+	}
+	fill_stat_data(&base, &st);
+	fputc('.', stderr);
+
+	avoid_racy();
+	write_or_die(fd, "data", 4);
+	close(fd);
+	xstat_mtime_dir(&st);
+	if (match_stat_data(&base, &st)) {
+		fputc('\n', stderr);
+		fprintf_ln(stderr, _("directory stat info changes "
+				     "after updating a file"));
+		goto done;
+	}
+	fputc('.', stderr);
+
+	avoid_racy();
+	close(create_file("new-dir/new"));
+	xstat_mtime_dir(&st);
+	if (match_stat_data(&base, &st)) {
+		fputc('\n', stderr);
+		fprintf_ln(stderr, _("directory stat info changes after "
+				     "adding a file inside subdirectory"));
+		goto done;
+	}
+	fputc('.', stderr);
+
+	avoid_racy();
+	xunlink("newfile");
+	xstat_mtime_dir(&st);
+	if (!match_stat_data(&base, &st)) {
+		fputc('\n', stderr);
+		fprintf_ln(stderr, _("directory stat info does not "
+				     "change after deleting a file"));
+		goto done;
+	}
+	fill_stat_data(&base, &st);
+	fputc('.', stderr);
+
+	avoid_racy();
+	xunlink("new-dir/new");
+	xrmdir("new-dir");
+	xstat_mtime_dir(&st);
+	if (!match_stat_data(&base, &st)) {
+		fputc('\n', stderr);
+		fprintf_ln(stderr, _("directory stat info does not "
+				     "change after deleting a directory"));
+		goto done;
+	}
+
+	if (rmdir(mtime_dir.buf))
+		die_errno(_("failed to delete directory %s"), mtime_dir.buf);
+	fprintf_ln(stderr, _(" OK"));
+	ret = 1;
+
+done:
+	strbuf_release(&mtime_dir);
+	return ret;
+}
+
+static int mark_ce_flags(const char *path, int flag, int mark)
+{
+	int namelen = strlen(path);
+	int pos = cache_name_pos(path, namelen);
+	if (0 <= pos) {
+		mark_fsmonitor_invalid(&the_index, active_cache[pos]);
+		if (mark)
+			active_cache[pos]->ce_flags |= flag;
+		else
+			active_cache[pos]->ce_flags &= ~flag;
+		active_cache[pos]->ce_flags |= CE_UPDATE_IN_BASE;
+		cache_tree_invalidate_path(&the_index, path);
+		active_cache_changed |= CE_ENTRY_CHANGED;
+		return 0;
+	}
+	return -1;
+}
+
+static int remove_one_path(const char *path)
+{
+	if (!allow_remove)
+		return error("%s: does not exist and --remove not passed", path);
+	if (remove_file_from_cache(path))
+		return error("%s: cannot remove from the index", path);
+	return 0;
+}
+
+/*
+ * Handle a path that couldn't be lstat'ed. It's either:
+ *  - missing file (ENOENT or ENOTDIR). That's ok if we're
+ *    supposed to be removing it and the removal actually
+ *    succeeds.
+ *  - permission error. That's never ok.
+ */
+static int process_lstat_error(const char *path, int err)
+{
+	if (is_missing_file_error(err))
+		return remove_one_path(path);
+	return error("lstat(\"%s\"): %s", path, strerror(err));
+}
+
+static int add_one_path(const struct cache_entry *old, const char *path, int len, struct stat *st)
+{
+	int option;
+	struct cache_entry *ce;
+
+	/* Was the old index entry already up-to-date? */
+	if (old && !ce_stage(old) && !ce_match_stat(old, st, 0))
+		return 0;
+
+	ce = make_empty_cache_entry(&the_index, len);
+	memcpy(ce->name, path, len);
+	ce->ce_flags = create_ce_flags(0);
+	ce->ce_namelen = len;
+	fill_stat_cache_info(&the_index, ce, st);
+	ce->ce_mode = ce_mode_from_stat(old, st->st_mode);
+
+	if (index_path(&the_index, &ce->oid, path, st,
+		       info_only ? 0 : HASH_WRITE_OBJECT)) {
+		discard_cache_entry(ce);
+		return -1;
+	}
+	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
+	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
+	if (add_cache_entry(ce, option)) {
+		discard_cache_entry(ce);
+		return error("%s: cannot add to the index - missing --add option?", path);
+	}
+	return 0;
+}
+
+/*
+ * Handle a path that was a directory. Four cases:
+ *
+ *  - it's already a gitlink in the index, and we keep it that
+ *    way, and update it if we can (if we cannot find the HEAD,
+ *    we're going to keep it unchanged in the index!)
+ *
+ *  - it's a *file* in the index, in which case it should be
+ *    removed as a file if removal is allowed, since it doesn't
+ *    exist as such any more. If removal isn't allowed, it's
+ *    an error.
+ *
+ *    (NOTE! This is old and arguably fairly strange behaviour.
+ *    We might want to make this an error unconditionally, and
+ *    use "--force-remove" if you actually want to force removal).
+ *
+ *  - it used to exist as a subdirectory (ie multiple files with
+ *    this particular prefix) in the index, in which case it's wrong
+ *    to try to update it as a directory.
+ *
+ *  - it doesn't exist at all in the index, but it is a valid
+ *    git directory, and it should be *added* as a gitlink.
+ */
+static int process_directory(const char *path, int len, struct stat *st)
+{
+	struct object_id oid;
+	int pos = cache_name_pos(path, len);
+
+	/* Exact match: file or existing gitlink */
+	if (pos >= 0) {
+		const struct cache_entry *ce = active_cache[pos];
+		if (S_ISGITLINK(ce->ce_mode)) {
+
+			/* Do nothing to the index if there is no HEAD! */
+			if (resolve_gitlink_ref(path, "HEAD", &oid) < 0)
+				return 0;
+
+			return add_one_path(ce, path, len, st);
+		}
+		/* Should this be an unconditional error? */
+		return remove_one_path(path);
+	}
+
+	/* Inexact match: is there perhaps a subdirectory match? */
+	pos = -pos-1;
+	while (pos < active_nr) {
+		const struct cache_entry *ce = active_cache[pos++];
+
+		if (strncmp(ce->name, path, len))
+			break;
+		if (ce->name[len] > '/')
+			break;
+		if (ce->name[len] < '/')
+			continue;
+
+		/* Subdirectory match - error out */
+		return error("%s: is a directory - add individual files instead", path);
+	}
+
+	/* No match - should we add it as a gitlink? */
+	if (!resolve_gitlink_ref(path, "HEAD", &oid))
+		return add_one_path(NULL, path, len, st);
+
+	/* Error out. */
+	return error("%s: is a directory - add files inside instead", path);
+}
+
+static int process_path(const char *path, struct stat *st, int stat_errno)
+{
+	int pos, len;
+	const struct cache_entry *ce;
+
+	len = strlen(path);
+	if (has_symlink_leading_path(path, len))
+		return error("'%s' is beyond a symbolic link", path);
+
+	pos = cache_name_pos(path, len);
+	ce = pos < 0 ? NULL : active_cache[pos];
+	if (ce && ce_skip_worktree(ce)) {
+		/*
+		 * working directory version is assumed "good"
+		 * so updating it does not make sense.
+		 * On the other hand, removing it from index should work
+		 */
+		if (allow_remove && remove_file_from_cache(path))
+			return error("%s: cannot remove from the index", path);
+		return 0;
+	}
+
+	/*
+	 * First things first: get the stat information, to decide
+	 * what to do about the pathname!
+	 */
+	if (stat_errno)
+		return process_lstat_error(path, stat_errno);
+
+	if (S_ISDIR(st->st_mode))
+		return process_directory(path, len, st);
+
+	return add_one_path(ce, path, len, st);
+}
+
+static int add_cacheinfo(unsigned int mode, const struct object_id *oid,
+			 const char *path, int stage)
+{
+	int len, option;
+	struct cache_entry *ce;
+
+	if (!verify_path(path, mode))
+		return error("Invalid path '%s'", path);
+
+	len = strlen(path);
+	ce = make_empty_cache_entry(&the_index, len);
+
+	oidcpy(&ce->oid, oid);
+	memcpy(ce->name, path, len);
+	ce->ce_flags = create_ce_flags(stage);
+	ce->ce_namelen = len;
+	ce->ce_mode = create_ce_mode(mode);
+	if (assume_unchanged)
+		ce->ce_flags |= CE_VALID;
+	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
+	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
+	if (add_cache_entry(ce, option))
+		return error("%s: cannot add to the index - missing --add option?",
+			     path);
+	report("add '%s'", path);
+	return 0;
+}
+
+static void chmod_path(char flip, const char *path)
+{
+	int pos;
+	struct cache_entry *ce;
+
+	pos = cache_name_pos(path, strlen(path));
+	if (pos < 0)
+		goto fail;
+	ce = active_cache[pos];
+	if (chmod_cache_entry(ce, flip) < 0)
+		goto fail;
+
+	report("chmod %cx '%s'", flip, path);
+	return;
+ fail:
+	die("git update-index: cannot chmod %cx '%s'", flip, path);
+}
+
+static void update_one(const char *path)
+{
+	int stat_errno = 0;
+	struct stat st;
+
+	if (mark_valid_only || mark_skip_worktree_only || force_remove ||
+	    mark_fsmonitor_only)
+		st.st_mode = 0;
+	else if (lstat(path, &st) < 0) {
+		st.st_mode = 0;
+		stat_errno = errno;
+	} /* else stat is valid */
+
+	if (!verify_path(path, st.st_mode)) {
+		fprintf(stderr, "Ignoring path %s\n", path);
+		return;
+	}
+	if (mark_valid_only) {
+		if (mark_ce_flags(path, CE_VALID, mark_valid_only == MARK_FLAG))
+			die("Unable to mark file %s", path);
+		return;
+	}
+	if (mark_skip_worktree_only) {
+		if (mark_ce_flags(path, CE_SKIP_WORKTREE, mark_skip_worktree_only == MARK_FLAG))
+			die("Unable to mark file %s", path);
+		return;
+	}
+	if (mark_fsmonitor_only) {
+		if (mark_ce_flags(path, CE_FSMONITOR_VALID, mark_fsmonitor_only == MARK_FLAG))
+			die("Unable to mark file %s", path);
+		return;
+	}
+
+	if (force_remove) {
+		if (remove_file_from_cache(path))
+			die("git update-index: unable to remove %s", path);
+		report("remove '%s'", path);
+		return;
+	}
+	if (process_path(path, &st, stat_errno))
+		die("Unable to process path %s", path);
+	report("add '%s'", path);
+}
+
+static void read_index_info(int nul_term_line)
+{
+	const int hexsz = the_hash_algo->hexsz;
+	struct strbuf buf = STRBUF_INIT;
+	struct strbuf uq = STRBUF_INIT;
+	strbuf_getline_fn getline_fn;
+
+	getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
+	while (getline_fn(&buf, stdin) != EOF) {
+		char *ptr, *tab;
+		char *path_name;
+		struct object_id oid;
+		unsigned int mode;
+		unsigned long ul;
+		int stage;
+
+		/* This reads lines formatted in one of three formats:
+		 *
+		 * (1) mode         SP sha1          TAB path
+		 * The first format is what "git apply --index-info"
+		 * reports, and used to reconstruct a partial tree
+		 * that is used for phony merge base tree when falling
+		 * back on 3-way merge.
+		 *
+		 * (2) mode SP type SP sha1          TAB path
+		 * The second format is to stuff "git ls-tree" output
+		 * into the index file.
+		 *
+		 * (3) mode         SP sha1 SP stage TAB path
+		 * This format is to put higher order stages into the
+		 * index file and matches "git ls-files --stage" output.
+		 */
+		errno = 0;
+		ul = strtoul(buf.buf, &ptr, 8);
+		if (ptr == buf.buf || *ptr != ' '
+		    || errno || (unsigned int) ul != ul)
+			goto bad_line;
+		mode = ul;
+
+		tab = strchr(ptr, '\t');
+		if (!tab || tab - ptr < hexsz + 1)
+			goto bad_line;
+
+		if (tab[-2] == ' ' && '0' <= tab[-1] && tab[-1] <= '3') {
+			stage = tab[-1] - '0';
+			ptr = tab + 1; /* point at the head of path */
+			tab = tab - 2; /* point at tail of sha1 */
+		}
+		else {
+			stage = 0;
+			ptr = tab + 1; /* point at the head of path */
+		}
+
+		if (get_oid_hex(tab - hexsz, &oid) ||
+			tab[-(hexsz + 1)] != ' ')
+			goto bad_line;
+
+		path_name = ptr;
+		if (!nul_term_line && path_name[0] == '"') {
+			strbuf_reset(&uq);
+			if (unquote_c_style(&uq, path_name, NULL)) {
+				die("git update-index: bad quoting of path name");
+			}
+			path_name = uq.buf;
+		}
+
+		if (!verify_path(path_name, mode)) {
+			fprintf(stderr, "Ignoring path %s\n", path_name);
+			continue;
+		}
+
+		if (!mode) {
+			/* mode == 0 means there is no such path -- remove */
+			if (remove_file_from_cache(path_name))
+				die("git update-index: unable to remove %s",
+				    ptr);
+		}
+		else {
+			/* mode ' ' sha1 '\t' name
+			 * ptr[-1] points at tab,
+			 * ptr[-41] is at the beginning of sha1
+			 */
+			ptr[-(hexsz + 2)] = ptr[-1] = 0;
+			if (add_cacheinfo(mode, &oid, path_name, stage))
+				die("git update-index: unable to update %s",
+				    path_name);
+		}
+		continue;
+
+	bad_line:
+		die("malformed index info %s", buf.buf);
+	}
+	strbuf_release(&buf);
+	strbuf_release(&uq);
+}
+
+static const char * const update_index_usage[] = {
+	N_("git update-index [<options>] [--] [<file>...]"),
+	NULL
+};
+
+static struct object_id head_oid;
+static struct object_id merge_head_oid;
+
+static struct cache_entry *read_one_ent(const char *which,
+					struct object_id *ent, const char *path,
+					int namelen, int stage)
+{
+	unsigned short mode;
+	struct object_id oid;
+	struct cache_entry *ce;
+
+	if (get_tree_entry(the_repository, ent, path, &oid, &mode)) {
+		if (which)
+			error("%s: not in %s branch.", path, which);
+		return NULL;
+	}
+	if (mode == S_IFDIR) {
+		if (which)
+			error("%s: not a blob in %s branch.", path, which);
+		return NULL;
+	}
+	ce = make_empty_cache_entry(&the_index, namelen);
+
+	oidcpy(&ce->oid, &oid);
+	memcpy(ce->name, path, namelen);
+	ce->ce_flags = create_ce_flags(stage);
+	ce->ce_namelen = namelen;
+	ce->ce_mode = create_ce_mode(mode);
+	return ce;
+}
+
+static int unresolve_one(const char *path)
+{
+	int namelen = strlen(path);
+	int pos;
+	int ret = 0;
+	struct cache_entry *ce_2 = NULL, *ce_3 = NULL;
+
+	/* See if there is such entry in the index. */
+	pos = cache_name_pos(path, namelen);
+	if (0 <= pos) {
+		/* already merged */
+		pos = unmerge_cache_entry_at(pos);
+		if (pos < active_nr) {
+			const struct cache_entry *ce = active_cache[pos];
+			if (ce_stage(ce) &&
+			    ce_namelen(ce) == namelen &&
+			    !memcmp(ce->name, path, namelen))
+				return 0;
+		}
+		/* no resolve-undo information; fall back */
+	} else {
+		/* If there isn't, either it is unmerged, or
+		 * resolved as "removed" by mistake.  We do not
+		 * want to do anything in the former case.
+		 */
+		pos = -pos-1;
+		if (pos < active_nr) {
+			const struct cache_entry *ce = active_cache[pos];
+			if (ce_namelen(ce) == namelen &&
+			    !memcmp(ce->name, path, namelen)) {
+				fprintf(stderr,
+					"%s: skipping still unmerged path.\n",
+					path);
+				goto free_return;
+			}
+		}
+	}
+
+	/* Grab blobs from given path from HEAD and MERGE_HEAD,
+	 * stuff HEAD version in stage #2,
+	 * stuff MERGE_HEAD version in stage #3.
+	 */
+	ce_2 = read_one_ent("our", &head_oid, path, namelen, 2);
+	ce_3 = read_one_ent("their", &merge_head_oid, path, namelen, 3);
+
+	if (!ce_2 || !ce_3) {
+		ret = -1;
+		goto free_return;
+	}
+	if (oideq(&ce_2->oid, &ce_3->oid) &&
+	    ce_2->ce_mode == ce_3->ce_mode) {
+		fprintf(stderr, "%s: identical in both, skipping.\n",
+			path);
+		goto free_return;
+	}
+
+	remove_file_from_cache(path);
+	if (add_cache_entry(ce_2, ADD_CACHE_OK_TO_ADD)) {
+		error("%s: cannot add our version to the index.", path);
+		ret = -1;
+		goto free_return;
+	}
+	if (!add_cache_entry(ce_3, ADD_CACHE_OK_TO_ADD))
+		return 0;
+	error("%s: cannot add their version to the index.", path);
+	ret = -1;
+ free_return:
+	discard_cache_entry(ce_2);
+	discard_cache_entry(ce_3);
+	return ret;
+}
+
+static void read_head_pointers(void)
+{
+	if (read_ref("HEAD", &head_oid))
+		die("No HEAD -- no initial commit yet?");
+	if (read_ref("MERGE_HEAD", &merge_head_oid)) {
+		fprintf(stderr, "Not in the middle of a merge.\n");
+		exit(0);
+	}
+}
+
+static int do_unresolve(int ac, const char **av,
+			const char *prefix, int prefix_length)
+{
+	int i;
+	int err = 0;
+
+	/* Read HEAD and MERGE_HEAD; if MERGE_HEAD does not exist, we
+	 * are not doing a merge, so exit with success status.
+	 */
+	read_head_pointers();
+
+	for (i = 1; i < ac; i++) {
+		const char *arg = av[i];
+		char *p = prefix_path(prefix, prefix_length, arg);
+		err |= unresolve_one(p);
+		free(p);
+	}
+	return err;
+}
+
+static int do_reupdate(int ac, const char **av,
+		       const char *prefix)
+{
+	/* Read HEAD and run update-index on paths that are
+	 * merged and already different between index and HEAD.
+	 */
+	int pos;
+	int has_head = 1;
+	struct pathspec pathspec;
+
+	parse_pathspec(&pathspec, 0,
+		       PATHSPEC_PREFER_CWD,
+		       prefix, av + 1);
+
+	if (read_ref("HEAD", &head_oid))
+		/* If there is no HEAD, that means it is an initial
+		 * commit.  Update everything in the index.
+		 */
+		has_head = 0;
+ redo:
+	for (pos = 0; pos < active_nr; pos++) {
+		const struct cache_entry *ce = active_cache[pos];
+		struct cache_entry *old = NULL;
+		int save_nr;
+		char *path;
+
+		if (ce_stage(ce) || !ce_path_match(&the_index, ce, &pathspec, NULL))
+			continue;
+		if (has_head)
+			old = read_one_ent(NULL, &head_oid,
+					   ce->name, ce_namelen(ce), 0);
+		if (old && ce->ce_mode == old->ce_mode &&
+		    oideq(&ce->oid, &old->oid)) {
+			discard_cache_entry(old);
+			continue; /* unchanged */
+		}
+		/* Be careful.  The working tree may not have the
+		 * path anymore, in which case, under 'allow_remove',
+		 * or worse yet 'allow_replace', active_nr may decrease.
+		 */
+		save_nr = active_nr;
+		path = xstrdup(ce->name);
+		update_one(path);
+		free(path);
+		discard_cache_entry(old);
+		if (save_nr != active_nr)
+			goto redo;
+	}
+	clear_pathspec(&pathspec);
+	return 0;
+}
+
+struct refresh_params {
+	unsigned int flags;
+	int *has_errors;
+};
+
+static int refresh(struct refresh_params *o, unsigned int flag)
+{
+	setup_work_tree();
+	read_cache();
+	*o->has_errors |= refresh_cache(o->flags | flag);
+	return 0;
+}
+
+static int refresh_callback(const struct option *opt,
+				const char *arg, int unset)
+{
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+	return refresh(opt->value, 0);
+}
+
+static int really_refresh_callback(const struct option *opt,
+				const char *arg, int unset)
+{
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+	return refresh(opt->value, REFRESH_REALLY);
+}
+
+static int chmod_callback(const struct option *opt,
+				const char *arg, int unset)
+{
+	char *flip = opt->value;
+	BUG_ON_OPT_NEG(unset);
+	if ((arg[0] != '-' && arg[0] != '+') || arg[1] != 'x' || arg[2])
+		return error("option 'chmod' expects \"+x\" or \"-x\"");
+	*flip = arg[0];
+	return 0;
+}
+
+static int resolve_undo_clear_callback(const struct option *opt,
+				const char *arg, int unset)
+{
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+	resolve_undo_clear();
+	return 0;
+}
+
+static int parse_new_style_cacheinfo(const char *arg,
+				     unsigned int *mode,
+				     struct object_id *oid,
+				     const char **path)
+{
+	unsigned long ul;
+	char *endp;
+	const char *p;
+
+	if (!arg)
+		return -1;
+
+	errno = 0;
+	ul = strtoul(arg, &endp, 8);
+	if (errno || endp == arg || *endp != ',' || (unsigned int) ul != ul)
+		return -1; /* not a new-style cacheinfo */
+	*mode = ul;
+	endp++;
+	if (parse_oid_hex(endp, oid, &p) || *p != ',')
+		return -1;
+	*path = p + 1;
+	return 0;
+}
+
+static enum parse_opt_result cacheinfo_callback(
+	struct parse_opt_ctx_t *ctx, const struct option *opt,
+	const char *arg, int unset)
+{
+	struct object_id oid;
+	unsigned int mode;
+	const char *path;
+
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
+	if (!parse_new_style_cacheinfo(ctx->argv[1], &mode, &oid, &path)) {
+		if (add_cacheinfo(mode, &oid, path, 0))
+			die("git update-index: --cacheinfo cannot add %s", path);
+		ctx->argv++;
+		ctx->argc--;
+		return 0;
+	}
+	if (ctx->argc <= 3)
+		return error("option 'cacheinfo' expects <mode>,<sha1>,<path>");
+	if (strtoul_ui(*++ctx->argv, 8, &mode) ||
+	    get_oid_hex(*++ctx->argv, &oid) ||
+	    add_cacheinfo(mode, &oid, *++ctx->argv, 0))
+		die("git update-index: --cacheinfo cannot add %s", *ctx->argv);
+	ctx->argc -= 3;
+	return 0;
+}
+
+static enum parse_opt_result stdin_cacheinfo_callback(
+	struct parse_opt_ctx_t *ctx, const struct option *opt,
+	const char *arg, int unset)
+{
+	int *nul_term_line = opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
+	if (ctx->argc != 1)
+		return error("option '%s' must be the last argument", opt->long_name);
+	allow_add = allow_replace = allow_remove = 1;
+	read_index_info(*nul_term_line);
+	return 0;
+}
+
+static enum parse_opt_result stdin_callback(
+	struct parse_opt_ctx_t *ctx, const struct option *opt,
+	const char *arg, int unset)
+{
+	int *read_from_stdin = opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
+	if (ctx->argc != 1)
+		return error("option '%s' must be the last argument", opt->long_name);
+	*read_from_stdin = 1;
+	return 0;
+}
+
+static enum parse_opt_result unresolve_callback(
+	struct parse_opt_ctx_t *ctx, const struct option *opt,
+	const char *arg, int unset)
+{
+	int *has_errors = opt->value;
+	const char *prefix = startup_info->prefix;
+
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
+	/* consume remaining arguments. */
+	*has_errors = do_unresolve(ctx->argc, ctx->argv,
+				prefix, prefix ? strlen(prefix) : 0);
+	if (*has_errors)
+		active_cache_changed = 0;
+
+	ctx->argv += ctx->argc - 1;
+	ctx->argc = 1;
+	return 0;
+}
+
+static enum parse_opt_result reupdate_callback(
+	struct parse_opt_ctx_t *ctx, const struct option *opt,
+	const char *arg, int unset)
+{
+	int *has_errors = opt->value;
+	const char *prefix = startup_info->prefix;
+
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
+	/* consume remaining arguments. */
+	setup_work_tree();
+	*has_errors = do_reupdate(ctx->argc, ctx->argv, prefix);
+	if (*has_errors)
+		active_cache_changed = 0;
+
+	ctx->argv += ctx->argc - 1;
+	ctx->argc = 1;
+	return 0;
+}
+
+int cmd_update_index(int argc, const char **argv, const char *prefix)
+{
+	int newfd, entries, has_errors = 0, nul_term_line = 0;
+	enum uc_mode untracked_cache = UC_UNSPECIFIED;
+	int read_from_stdin = 0;
+	int prefix_length = prefix ? strlen(prefix) : 0;
+	int preferred_index_format = 0;
+	char set_executable_bit = 0;
+	struct refresh_params refresh_args = {0, &has_errors};
+	int lock_error = 0;
+	int split_index = -1;
+	int force_write = 0;
+	int fsmonitor = -1;
+	struct lock_file lock_file = LOCK_INIT;
+	struct parse_opt_ctx_t ctx;
+	strbuf_getline_fn getline_fn;
+	int parseopt_state = PARSE_OPT_UNKNOWN;
+	struct option options[] = {
+		OPT_BIT('q', NULL, &refresh_args.flags,
+			N_("continue refresh even when index needs update"),
+			REFRESH_QUIET),
+		OPT_BIT(0, "ignore-submodules", &refresh_args.flags,
+			N_("refresh: ignore submodules"),
+			REFRESH_IGNORE_SUBMODULES),
+		OPT_SET_INT(0, "add", &allow_add,
+			N_("do not ignore new files"), 1),
+		OPT_SET_INT(0, "replace", &allow_replace,
+			N_("let files replace directories and vice-versa"), 1),
+		OPT_SET_INT(0, "remove", &allow_remove,
+			N_("notice files missing from worktree"), 1),
+		OPT_BIT(0, "unmerged", &refresh_args.flags,
+			N_("refresh even if index contains unmerged entries"),
+			REFRESH_UNMERGED),
+		{OPTION_CALLBACK, 0, "refresh", &refresh_args, NULL,
+			N_("refresh stat information"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
+			refresh_callback},
+		{OPTION_CALLBACK, 0, "really-refresh", &refresh_args, NULL,
+			N_("like --refresh, but ignore assume-unchanged setting"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
+			really_refresh_callback},
+		{OPTION_LOWLEVEL_CALLBACK, 0, "cacheinfo", NULL,
+			N_("<mode>,<object>,<path>"),
+			N_("add the specified entry to the index"),
+			PARSE_OPT_NOARG | /* disallow --cacheinfo=<mode> form */
+			PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP,
+			NULL, 0,
+			cacheinfo_callback},
+		{OPTION_CALLBACK, 0, "chmod", &set_executable_bit, "(+|-)x",
+			N_("override the executable bit of the listed files"),
+			PARSE_OPT_NONEG,
+			chmod_callback},
+		{OPTION_SET_INT, 0, "assume-unchanged", &mark_valid_only, NULL,
+			N_("mark files as \"not changing\""),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, MARK_FLAG},
+		{OPTION_SET_INT, 0, "no-assume-unchanged", &mark_valid_only, NULL,
+			N_("clear assumed-unchanged bit"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, UNMARK_FLAG},
+		{OPTION_SET_INT, 0, "skip-worktree", &mark_skip_worktree_only, NULL,
+			N_("mark files as \"index-only\""),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, MARK_FLAG},
+		{OPTION_SET_INT, 0, "no-skip-worktree", &mark_skip_worktree_only, NULL,
+			N_("clear skip-worktree bit"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, UNMARK_FLAG},
+		OPT_SET_INT(0, "info-only", &info_only,
+			N_("add to index only; do not add content to object database"), 1),
+		OPT_SET_INT(0, "force-remove", &force_remove,
+			N_("remove named paths even if present in worktree"), 1),
+		OPT_BOOL('z', NULL, &nul_term_line,
+			 N_("with --stdin: input lines are terminated by null bytes")),
+		{OPTION_LOWLEVEL_CALLBACK, 0, "stdin", &read_from_stdin, NULL,
+			N_("read list of paths to be updated from standard input"),
+			PARSE_OPT_NONEG | PARSE_OPT_NOARG,
+			NULL, 0, stdin_callback},
+		{OPTION_LOWLEVEL_CALLBACK, 0, "index-info", &nul_term_line, NULL,
+			N_("add entries from standard input to the index"),
+			PARSE_OPT_NONEG | PARSE_OPT_NOARG,
+			NULL, 0, stdin_cacheinfo_callback},
+		{OPTION_LOWLEVEL_CALLBACK, 0, "unresolve", &has_errors, NULL,
+			N_("repopulate stages #2 and #3 for the listed paths"),
+			PARSE_OPT_NONEG | PARSE_OPT_NOARG,
+			NULL, 0, unresolve_callback},
+		{OPTION_LOWLEVEL_CALLBACK, 'g', "again", &has_errors, NULL,
+			N_("only update entries that differ from HEAD"),
+			PARSE_OPT_NONEG | PARSE_OPT_NOARG,
+			NULL, 0, reupdate_callback},
+		OPT_BIT(0, "ignore-missing", &refresh_args.flags,
+			N_("ignore files missing from worktree"),
+			REFRESH_IGNORE_MISSING),
+		OPT_SET_INT(0, "verbose", &verbose,
+			N_("report actions to standard output"), 1),
+		{OPTION_CALLBACK, 0, "clear-resolve-undo", NULL, NULL,
+			N_("(for porcelains) forget saved unresolved conflicts"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
+			resolve_undo_clear_callback},
+		OPT_INTEGER(0, "index-version", &preferred_index_format,
+			N_("write index in this format")),
+		OPT_BOOL(0, "split-index", &split_index,
+			N_("enable or disable split index")),
+		OPT_BOOL(0, "untracked-cache", &untracked_cache,
+			N_("enable/disable untracked cache")),
+		OPT_SET_INT(0, "test-untracked-cache", &untracked_cache,
+			    N_("test if the filesystem supports untracked cache"), UC_TEST),
+		OPT_SET_INT(0, "force-untracked-cache", &untracked_cache,
+			    N_("enable untracked cache without testing the filesystem"), UC_FORCE),
+		OPT_SET_INT(0, "force-write-index", &force_write,
+			N_("write out the index even if is not flagged as changed"), 1),
+		OPT_BOOL(0, "fsmonitor", &fsmonitor,
+			N_("enable or disable file system monitor")),
+		{OPTION_SET_INT, 0, "fsmonitor-valid", &mark_fsmonitor_only, NULL,
+			N_("mark files as fsmonitor valid"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, MARK_FLAG},
+		{OPTION_SET_INT, 0, "no-fsmonitor-valid", &mark_fsmonitor_only, NULL,
+			N_("clear fsmonitor valid bit"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, UNMARK_FLAG},
+		OPT_END()
+	};
+
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(update_index_usage, options);
+
+	git_config(git_default_config, NULL);
+
+	/* we will diagnose later if it turns out that we need to update it */
+	newfd = hold_locked_index(&lock_file, 0);
+	if (newfd < 0)
+		lock_error = errno;
+
+	entries = read_cache();
+	if (entries < 0)
+		die("cache corrupted");
+
+	the_index.updated_skipworktree = 1;
+
+	/*
+	 * Custom copy of parse_options() because we want to handle
+	 * filename arguments as they come.
+	 */
+	parse_options_start(&ctx, argc, argv, prefix,
+			    options, PARSE_OPT_STOP_AT_NON_OPTION);
+	while (ctx.argc) {
+		if (parseopt_state != PARSE_OPT_DONE)
+			parseopt_state = parse_options_step(&ctx, options,
+							    update_index_usage);
+		if (!ctx.argc)
+			break;
+		switch (parseopt_state) {
+		case PARSE_OPT_HELP:
+		case PARSE_OPT_ERROR:
+			exit(129);
+		case PARSE_OPT_COMPLETE:
+			exit(0);
+		case PARSE_OPT_NON_OPTION:
+		case PARSE_OPT_DONE:
+		{
+			const char *path = ctx.argv[0];
+			char *p;
+
+			setup_work_tree();
+			p = prefix_path(prefix, prefix_length, path);
+			update_one(p);
+			if (set_executable_bit)
+				chmod_path(set_executable_bit, p);
+			free(p);
+			ctx.argc--;
+			ctx.argv++;
+			break;
+		}
+		case PARSE_OPT_UNKNOWN:
+			if (ctx.argv[0][1] == '-')
+				error("unknown option '%s'", ctx.argv[0] + 2);
+			else
+				error("unknown switch '%c'", *ctx.opt);
+			usage_with_options(update_index_usage, options);
+		}
+	}
+	argc = parse_options_end(&ctx);
+
+	getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
+	if (preferred_index_format) {
+		if (preferred_index_format < INDEX_FORMAT_LB ||
+		    INDEX_FORMAT_UB < preferred_index_format)
+			die("index-version %d not in range: %d..%d",
+			    preferred_index_format,
+			    INDEX_FORMAT_LB, INDEX_FORMAT_UB);
+
+		if (the_index.version != preferred_index_format)
+			active_cache_changed |= SOMETHING_CHANGED;
+		the_index.version = preferred_index_format;
+	}
+
+	if (read_from_stdin) {
+		struct strbuf buf = STRBUF_INIT;
+		struct strbuf unquoted = STRBUF_INIT;
+
+		setup_work_tree();
+		while (getline_fn(&buf, stdin) != EOF) {
+			char *p;
+			if (!nul_term_line && buf.buf[0] == '"') {
+				strbuf_reset(&unquoted);
+				if (unquote_c_style(&unquoted, buf.buf, NULL))
+					die("line is badly quoted");
+				strbuf_swap(&buf, &unquoted);
+			}
+			p = prefix_path(prefix, prefix_length, buf.buf);
+			update_one(p);
+			if (set_executable_bit)
+				chmod_path(set_executable_bit, p);
+			free(p);
+		}
+		strbuf_release(&unquoted);
+		strbuf_release(&buf);
+	}
+
+	if (split_index > 0) {
+		if (git_config_get_split_index() == 0)
+			warning(_("core.splitIndex is set to false; "
+				  "remove or change it, if you really want to "
+				  "enable split index"));
+		if (the_index.split_index)
+			the_index.cache_changed |= SPLIT_INDEX_ORDERED;
+		else
+			add_split_index(&the_index);
+	} else if (!split_index) {
+		if (git_config_get_split_index() == 1)
+			warning(_("core.splitIndex is set to true; "
+				  "remove or change it, if you really want to "
+				  "disable split index"));
+		remove_split_index(&the_index);
+	}
+
+	switch (untracked_cache) {
+	case UC_UNSPECIFIED:
+		break;
+	case UC_DISABLE:
+		if (git_config_get_untracked_cache() == 1)
+			warning(_("core.untrackedCache is set to true; "
+				  "remove or change it, if you really want to "
+				  "disable the untracked cache"));
+		remove_untracked_cache(&the_index);
+		report(_("Untracked cache disabled"));
+		break;
+	case UC_TEST:
+		setup_work_tree();
+		return !test_if_untracked_cache_is_supported();
+	case UC_ENABLE:
+	case UC_FORCE:
+		if (git_config_get_untracked_cache() == 0)
+			warning(_("core.untrackedCache is set to false; "
+				  "remove or change it, if you really want to "
+				  "enable the untracked cache"));
+		add_untracked_cache(&the_index);
+		report(_("Untracked cache enabled for '%s'"), get_git_work_tree());
+		break;
+	default:
+		BUG("bad untracked_cache value: %d", untracked_cache);
+	}
+
+	if (fsmonitor > 0) {
+		if (git_config_get_fsmonitor() == 0)
+			warning(_("core.fsmonitor is unset; "
+				"set it if you really want to "
+				"enable fsmonitor"));
+		add_fsmonitor(&the_index);
+		report(_("fsmonitor enabled"));
+	} else if (!fsmonitor) {
+		if (git_config_get_fsmonitor() == 1)
+			warning(_("core.fsmonitor is set; "
+				"remove it if you really want to "
+				"disable fsmonitor"));
+		remove_fsmonitor(&the_index);
+		report(_("fsmonitor disabled"));
+	}
+
+	if (active_cache_changed || force_write) {
+		if (newfd < 0) {
+			if (refresh_args.flags & REFRESH_QUIET)
+				exit(128);
+			unable_to_lock_die(get_index_file(), lock_error);
+		}
+		if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
+			die("Unable to write new index file");
+	}
+
+	rollback_lock_file(&lock_file);
+
+	return has_errors ? 1 : 0;
+}