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

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

1 files changed, 976 insertions, 0 deletions

diff --git a/third_party/git/builtin/fsck.c b/third_party/git/builtin/fsck.c
new file mode 100644
index 000000000000..18403a94fa42
--- /dev/null
+++ b/third_party/git/builtin/fsck.c
@@ -0,0 +1,976 @@
+#define USE_THE_INDEX_COMPATIBILITY_MACROS
+#include "builtin.h"
+#include "cache.h"
+#include "repository.h"
+#include "config.h"
+#include "commit.h"
+#include "tree.h"
+#include "blob.h"
+#include "tag.h"
+#include "refs.h"
+#include "pack.h"
+#include "cache-tree.h"
+#include "tree-walk.h"
+#include "fsck.h"
+#include "parse-options.h"
+#include "dir.h"
+#include "progress.h"
+#include "streaming.h"
+#include "decorate.h"
+#include "packfile.h"
+#include "object-store.h"
+#include "run-command.h"
+#include "worktree.h"
+
+#define REACHABLE 0x0001
+#define SEEN      0x0002
+#define HAS_OBJ   0x0004
+/* This flag is set if something points to this object. */
+#define USED      0x0008
+
+static int show_root;
+static int show_tags;
+static int show_unreachable;
+static int include_reflogs = 1;
+static int check_full = 1;
+static int connectivity_only;
+static int check_strict;
+static int keep_cache_objects;
+static struct fsck_options fsck_walk_options = FSCK_OPTIONS_DEFAULT;
+static struct fsck_options fsck_obj_options = FSCK_OPTIONS_DEFAULT;
+static int errors_found;
+static int write_lost_and_found;
+static int verbose;
+static int show_progress = -1;
+static int show_dangling = 1;
+static int name_objects;
+#define ERROR_OBJECT 01
+#define ERROR_REACHABLE 02
+#define ERROR_PACK 04
+#define ERROR_REFS 010
+#define ERROR_COMMIT_GRAPH 020
+
+static const char *describe_object(struct object *obj)
+{
+	static struct strbuf bufs[] = {
+		STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
+	};
+	static int b = 0;
+	struct strbuf *buf;
+	char *name = NULL;
+
+	if (name_objects)
+		name = lookup_decoration(fsck_walk_options.object_names, obj);
+
+	buf = bufs + b;
+	b = (b + 1) % ARRAY_SIZE(bufs);
+	strbuf_reset(buf);
+	strbuf_addstr(buf, oid_to_hex(&obj->oid));
+	if (name)
+		strbuf_addf(buf, " (%s)", name);
+
+	return buf->buf;
+}
+
+static const char *printable_type(struct object *obj)
+{
+	const char *ret;
+
+	if (obj->type == OBJ_NONE) {
+		enum object_type type = oid_object_info(the_repository,
+							&obj->oid, NULL);
+		if (type > 0)
+			object_as_type(the_repository, obj, type, 0);
+	}
+
+	ret = type_name(obj->type);
+	if (!ret)
+		ret = _("unknown");
+
+	return ret;
+}
+
+static int fsck_config(const char *var, const char *value, void *cb)
+{
+	if (strcmp(var, "fsck.skiplist") == 0) {
+		const char *path;
+		struct strbuf sb = STRBUF_INIT;
+
+		if (git_config_pathname(&path, var, value))
+			return 1;
+		strbuf_addf(&sb, "skiplist=%s", path);
+		free((char *)path);
+		fsck_set_msg_types(&fsck_obj_options, sb.buf);
+		strbuf_release(&sb);
+		return 0;
+	}
+
+	if (skip_prefix(var, "fsck.", &var)) {
+		fsck_set_msg_type(&fsck_obj_options, var, value);
+		return 0;
+	}
+
+	return git_default_config(var, value, cb);
+}
+
+static int objerror(struct object *obj, const char *err)
+{
+	errors_found |= ERROR_OBJECT;
+	/* TRANSLATORS: e.g. error in tree 01bfda: <more explanation> */
+	fprintf_ln(stderr, _("error in %s %s: %s"),
+		   printable_type(obj), describe_object(obj), err);
+	return -1;
+}
+
+static int fsck_error_func(struct fsck_options *o,
+	struct object *obj, int type, const char *message)
+{
+	switch (type) {
+	case FSCK_WARN:
+		/* TRANSLATORS: e.g. warning in tree 01bfda: <more explanation> */
+		fprintf_ln(stderr, _("warning in %s %s: %s"),
+			   printable_type(obj), describe_object(obj), message);
+		return 0;
+	case FSCK_ERROR:
+		/* TRANSLATORS: e.g. error in tree 01bfda: <more explanation> */
+		fprintf_ln(stderr, _("error in %s %s: %s"),
+			   printable_type(obj), describe_object(obj), message);
+		return 1;
+	default:
+		BUG("%d (FSCK_IGNORE?) should never trigger this callback", type);
+	}
+}
+
+static struct object_array pending;
+
+static int mark_object(struct object *obj, int type, void *data, struct fsck_options *options)
+{
+	struct object *parent = data;
+
+	/*
+	 * The only case data is NULL or type is OBJ_ANY is when
+	 * mark_object_reachable() calls us.  All the callers of
+	 * that function has non-NULL obj hence ...
+	 */
+	if (!obj) {
+		/* ... these references to parent->fld are safe here */
+		printf_ln(_("broken link from %7s %s"),
+			  printable_type(parent), describe_object(parent));
+		printf_ln(_("broken link from %7s %s"),
+			  (type == OBJ_ANY ? _("unknown") : type_name(type)),
+			  _("unknown"));
+		errors_found |= ERROR_REACHABLE;
+		return 1;
+	}
+
+	if (type != OBJ_ANY && obj->type != type)
+		/* ... and the reference to parent is safe here */
+		objerror(parent, _("wrong object type in link"));
+
+	if (obj->flags & REACHABLE)
+		return 0;
+	obj->flags |= REACHABLE;
+
+	if (is_promisor_object(&obj->oid))
+		/*
+		 * Further recursion does not need to be performed on this
+		 * object since it is a promisor object (so it does not need to
+		 * be added to "pending").
+		 */
+		return 0;
+
+	if (!(obj->flags & HAS_OBJ)) {
+		if (parent && !has_object_file(&obj->oid)) {
+			printf_ln(_("broken link from %7s %s\n"
+				    "              to %7s %s"),
+				  printable_type(parent),
+				  describe_object(parent),
+				  printable_type(obj),
+				  describe_object(obj));
+			errors_found |= ERROR_REACHABLE;
+		}
+		return 1;
+	}
+
+	add_object_array(obj, NULL, &pending);
+	return 0;
+}
+
+static void mark_object_reachable(struct object *obj)
+{
+	mark_object(obj, OBJ_ANY, NULL, NULL);
+}
+
+static int traverse_one_object(struct object *obj)
+{
+	int result = fsck_walk(obj, obj, &fsck_walk_options);
+
+	if (obj->type == OBJ_TREE) {
+		struct tree *tree = (struct tree *)obj;
+		free_tree_buffer(tree);
+	}
+	return result;
+}
+
+static int traverse_reachable(void)
+{
+	struct progress *progress = NULL;
+	unsigned int nr = 0;
+	int result = 0;
+	if (show_progress)
+		progress = start_delayed_progress(_("Checking connectivity"), 0);
+	while (pending.nr) {
+		result |= traverse_one_object(object_array_pop(&pending));
+		display_progress(progress, ++nr);
+	}
+	stop_progress(&progress);
+	return !!result;
+}
+
+static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
+{
+	if (!obj)
+		return 1;
+	obj->flags |= USED;
+	return 0;
+}
+
+static void mark_unreachable_referents(const struct object_id *oid)
+{
+	struct fsck_options options = FSCK_OPTIONS_DEFAULT;
+	struct object *obj = lookup_object(the_repository, oid);
+
+	if (!obj || !(obj->flags & HAS_OBJ))
+		return; /* not part of our original set */
+	if (obj->flags & REACHABLE)
+		return; /* reachable objects already traversed */
+
+	/*
+	 * Avoid passing OBJ_NONE to fsck_walk, which will parse the object
+	 * (and we want to avoid parsing blobs).
+	 */
+	if (obj->type == OBJ_NONE) {
+		enum object_type type = oid_object_info(the_repository,
+							&obj->oid, NULL);
+		if (type > 0)
+			object_as_type(the_repository, obj, type, 0);
+	}
+
+	options.walk = mark_used;
+	fsck_walk(obj, NULL, &options);
+}
+
+static int mark_loose_unreachable_referents(const struct object_id *oid,
+					    const char *path,
+					    void *data)
+{
+	mark_unreachable_referents(oid);
+	return 0;
+}
+
+static int mark_packed_unreachable_referents(const struct object_id *oid,
+					     struct packed_git *pack,
+					     uint32_t pos,
+					     void *data)
+{
+	mark_unreachable_referents(oid);
+	return 0;
+}
+
+/*
+ * Check a single reachable object
+ */
+static void check_reachable_object(struct object *obj)
+{
+	/*
+	 * We obviously want the object to be parsed,
+	 * except if it was in a pack-file and we didn't
+	 * do a full fsck
+	 */
+	if (!(obj->flags & HAS_OBJ)) {
+		if (is_promisor_object(&obj->oid))
+			return;
+		if (has_object_pack(&obj->oid))
+			return; /* it is in pack - forget about it */
+		printf_ln(_("missing %s %s"), printable_type(obj),
+			  describe_object(obj));
+		errors_found |= ERROR_REACHABLE;
+		return;
+	}
+}
+
+/*
+ * Check a single unreachable object
+ */
+static void check_unreachable_object(struct object *obj)
+{
+	/*
+	 * Missing unreachable object? Ignore it. It's not like
+	 * we miss it (since it can't be reached), nor do we want
+	 * to complain about it being unreachable (since it does
+	 * not exist).
+	 */
+	if (!(obj->flags & HAS_OBJ))
+		return;
+
+	/*
+	 * Unreachable object that exists? Show it if asked to,
+	 * since this is something that is prunable.
+	 */
+	if (show_unreachable) {
+		printf_ln(_("unreachable %s %s"), printable_type(obj),
+			  describe_object(obj));
+		return;
+	}
+
+	/*
+	 * "!USED" means that nothing at all points to it, including
+	 * other unreachable objects. In other words, it's the "tip"
+	 * of some set of unreachable objects, usually a commit that
+	 * got dropped.
+	 *
+	 * Such starting points are more interesting than some random
+	 * set of unreachable objects, so we show them even if the user
+	 * hasn't asked for _all_ unreachable objects. If you have
+	 * deleted a branch by mistake, this is a prime candidate to
+	 * start looking at, for example.
+	 */
+	if (!(obj->flags & USED)) {
+		if (show_dangling)
+			printf_ln(_("dangling %s %s"), printable_type(obj),
+				  describe_object(obj));
+		if (write_lost_and_found) {
+			char *filename = git_pathdup("lost-found/%s/%s",
+				obj->type == OBJ_COMMIT ? "commit" : "other",
+				describe_object(obj));
+			FILE *f;
+
+			if (safe_create_leading_directories_const(filename)) {
+				error(_("could not create lost-found"));
+				free(filename);
+				return;
+			}
+			f = xfopen(filename, "w");
+			if (obj->type == OBJ_BLOB) {
+				if (stream_blob_to_fd(fileno(f), &obj->oid, NULL, 1))
+					die_errno(_("could not write '%s'"), filename);
+			} else
+				fprintf(f, "%s\n", describe_object(obj));
+			if (fclose(f))
+				die_errno(_("could not finish '%s'"),
+					  filename);
+			free(filename);
+		}
+		return;
+	}
+
+	/*
+	 * Otherwise? It's there, it's unreachable, and some other unreachable
+	 * object points to it. Ignore it - it's not interesting, and we showed
+	 * all the interesting cases above.
+	 */
+}
+
+static void check_object(struct object *obj)
+{
+	if (verbose)
+		fprintf_ln(stderr, _("Checking %s"), describe_object(obj));
+
+	if (obj->flags & REACHABLE)
+		check_reachable_object(obj);
+	else
+		check_unreachable_object(obj);
+}
+
+static void check_connectivity(void)
+{
+	int i, max;
+
+	/* Traverse the pending reachable objects */
+	traverse_reachable();
+
+	/*
+	 * With --connectivity-only, we won't have actually opened and marked
+	 * unreachable objects with USED. Do that now to make --dangling, etc
+	 * accurate.
+	 */
+	if (connectivity_only && (show_dangling || write_lost_and_found)) {
+		/*
+		 * Even though we already have a "struct object" for each of
+		 * these in memory, we must not iterate over the internal
+		 * object hash as we do below. Our loop would potentially
+		 * resize the hash, making our iteration invalid.
+		 *
+		 * Instead, we'll just go back to the source list of objects,
+		 * and ignore any that weren't present in our earlier
+		 * traversal.
+		 */
+		for_each_loose_object(mark_loose_unreachable_referents, NULL, 0);
+		for_each_packed_object(mark_packed_unreachable_referents, NULL, 0);
+	}
+
+	/* Look up all the requirements, warn about missing objects.. */
+	max = get_max_object_index();
+	if (verbose)
+		fprintf_ln(stderr, _("Checking connectivity (%d objects)"), max);
+
+	for (i = 0; i < max; i++) {
+		struct object *obj = get_indexed_object(i);
+
+		if (obj)
+			check_object(obj);
+	}
+}
+
+static int fsck_obj(struct object *obj, void *buffer, unsigned long size)
+{
+	int err;
+
+	if (obj->flags & SEEN)
+		return 0;
+	obj->flags |= SEEN;
+
+	if (verbose)
+		fprintf_ln(stderr, _("Checking %s %s"),
+			   printable_type(obj), describe_object(obj));
+
+	if (fsck_walk(obj, NULL, &fsck_obj_options))
+		objerror(obj, _("broken links"));
+	err = fsck_object(obj, buffer, size, &fsck_obj_options);
+	if (err)
+		goto out;
+
+	if (obj->type == OBJ_COMMIT) {
+		struct commit *commit = (struct commit *) obj;
+
+		if (!commit->parents && show_root)
+			printf_ln(_("root %s"),
+				  describe_object(&commit->object));
+	}
+
+	if (obj->type == OBJ_TAG) {
+		struct tag *tag = (struct tag *) obj;
+
+		if (show_tags && tag->tagged) {
+			printf_ln(_("tagged %s %s (%s) in %s"),
+				  printable_type(tag->tagged),
+				  describe_object(tag->tagged),
+				  tag->tag,
+				  describe_object(&tag->object));
+		}
+	}
+
+out:
+	if (obj->type == OBJ_TREE)
+		free_tree_buffer((struct tree *)obj);
+	if (obj->type == OBJ_COMMIT)
+		free_commit_buffer(the_repository->parsed_objects,
+				   (struct commit *)obj);
+	return err;
+}
+
+static int fsck_obj_buffer(const struct object_id *oid, enum object_type type,
+			   unsigned long size, void *buffer, int *eaten)
+{
+	/*
+	 * Note, buffer may be NULL if type is OBJ_BLOB. See
+	 * verify_packfile(), data_valid variable for details.
+	 */
+	struct object *obj;
+	obj = parse_object_buffer(the_repository, oid, type, size, buffer,
+				  eaten);
+	if (!obj) {
+		errors_found |= ERROR_OBJECT;
+		return error(_("%s: object corrupt or missing"),
+			     oid_to_hex(oid));
+	}
+	obj->flags &= ~(REACHABLE | SEEN);
+	obj->flags |= HAS_OBJ;
+	return fsck_obj(obj, buffer, size);
+}
+
+static int default_refs;
+
+static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
+	timestamp_t timestamp)
+{
+	struct object *obj;
+
+	if (!is_null_oid(oid)) {
+		obj = lookup_object(the_repository, oid);
+		if (obj && (obj->flags & HAS_OBJ)) {
+			if (timestamp && name_objects)
+				add_decoration(fsck_walk_options.object_names,
+					obj,
+					xstrfmt("%s@{%"PRItime"}", refname, timestamp));
+			obj->flags |= USED;
+			mark_object_reachable(obj);
+		} else if (!is_promisor_object(oid)) {
+			error(_("%s: invalid reflog entry %s"),
+			      refname, oid_to_hex(oid));
+			errors_found |= ERROR_REACHABLE;
+		}
+	}
+}
+
+static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
+		const char *email, timestamp_t timestamp, int tz,
+		const char *message, void *cb_data)
+{
+	const char *refname = cb_data;
+
+	if (verbose)
+		fprintf_ln(stderr, _("Checking reflog %s->%s"),
+			   oid_to_hex(ooid), oid_to_hex(noid));
+
+	fsck_handle_reflog_oid(refname, ooid, 0);
+	fsck_handle_reflog_oid(refname, noid, timestamp);
+	return 0;
+}
+
+static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
+			      int flag, void *cb_data)
+{
+	struct strbuf refname = STRBUF_INIT;
+
+	strbuf_worktree_ref(cb_data, &refname, logname);
+	for_each_reflog_ent(refname.buf, fsck_handle_reflog_ent, refname.buf);
+	strbuf_release(&refname);
+	return 0;
+}
+
+static int fsck_handle_ref(const char *refname, const struct object_id *oid,
+			   int flag, void *cb_data)
+{
+	struct object *obj;
+
+	obj = parse_object(the_repository, oid);
+	if (!obj) {
+		if (is_promisor_object(oid)) {
+			/*
+			 * Increment default_refs anyway, because this is a
+			 * valid ref.
+			 */
+			 default_refs++;
+			 return 0;
+		}
+		error(_("%s: invalid sha1 pointer %s"),
+		      refname, oid_to_hex(oid));
+		errors_found |= ERROR_REACHABLE;
+		/* We'll continue with the rest despite the error.. */
+		return 0;
+	}
+	if (obj->type != OBJ_COMMIT && is_branch(refname)) {
+		error(_("%s: not a commit"), refname);
+		errors_found |= ERROR_REFS;
+	}
+	default_refs++;
+	obj->flags |= USED;
+	if (name_objects)
+		add_decoration(fsck_walk_options.object_names,
+			obj, xstrdup(refname));
+	mark_object_reachable(obj);
+
+	return 0;
+}
+
+static int fsck_head_link(const char *head_ref_name,
+			  const char **head_points_at,
+			  struct object_id *head_oid);
+
+static void get_default_heads(void)
+{
+	struct worktree **worktrees, **p;
+	const char *head_points_at;
+	struct object_id head_oid;
+
+	for_each_rawref(fsck_handle_ref, NULL);
+
+	worktrees = get_worktrees(0);
+	for (p = worktrees; *p; p++) {
+		struct worktree *wt = *p;
+		struct strbuf ref = STRBUF_INIT;
+
+		strbuf_worktree_ref(wt, &ref, "HEAD");
+		fsck_head_link(ref.buf, &head_points_at, &head_oid);
+		if (head_points_at && !is_null_oid(&head_oid))
+			fsck_handle_ref(ref.buf, &head_oid, 0, NULL);
+		strbuf_release(&ref);
+
+		if (include_reflogs)
+			refs_for_each_reflog(get_worktree_ref_store(wt),
+					     fsck_handle_reflog, wt);
+	}
+	free_worktrees(worktrees);
+
+	/*
+	 * Not having any default heads isn't really fatal, but
+	 * it does mean that "--unreachable" no longer makes any
+	 * sense (since in this case everything will obviously
+	 * be unreachable by definition.
+	 *
+	 * Showing dangling objects is valid, though (as those
+	 * dangling objects are likely lost heads).
+	 *
+	 * So we just print a warning about it, and clear the
+	 * "show_unreachable" flag.
+	 */
+	if (!default_refs) {
+		fprintf_ln(stderr, _("notice: No default references"));
+		show_unreachable = 0;
+	}
+}
+
+static int fsck_loose(const struct object_id *oid, const char *path, void *data)
+{
+	struct object *obj;
+	enum object_type type;
+	unsigned long size;
+	void *contents;
+	int eaten;
+
+	if (read_loose_object(path, oid, &type, &size, &contents) < 0) {
+		errors_found |= ERROR_OBJECT;
+		error(_("%s: object corrupt or missing: %s"),
+		      oid_to_hex(oid), path);
+		return 0; /* keep checking other objects */
+	}
+
+	if (!contents && type != OBJ_BLOB)
+		BUG("read_loose_object streamed a non-blob");
+
+	obj = parse_object_buffer(the_repository, oid, type, size,
+				  contents, &eaten);
+
+	if (!obj) {
+		errors_found |= ERROR_OBJECT;
+		error(_("%s: object could not be parsed: %s"),
+		      oid_to_hex(oid), path);
+		if (!eaten)
+			free(contents);
+		return 0; /* keep checking other objects */
+	}
+
+	obj->flags &= ~(REACHABLE | SEEN);
+	obj->flags |= HAS_OBJ;
+	if (fsck_obj(obj, contents, size))
+		errors_found |= ERROR_OBJECT;
+
+	if (!eaten)
+		free(contents);
+	return 0; /* keep checking other objects, even if we saw an error */
+}
+
+static int fsck_cruft(const char *basename, const char *path, void *data)
+{
+	if (!starts_with(basename, "tmp_obj_"))
+		fprintf_ln(stderr, _("bad sha1 file: %s"), path);
+	return 0;
+}
+
+static int fsck_subdir(unsigned int nr, const char *path, void *progress)
+{
+	display_progress(progress, nr + 1);
+	return 0;
+}
+
+static void fsck_object_dir(const char *path)
+{
+	struct progress *progress = NULL;
+
+	if (verbose)
+		fprintf_ln(stderr, _("Checking object directory"));
+
+	if (show_progress)
+		progress = start_progress(_("Checking object directories"), 256);
+
+	for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
+				      progress);
+	display_progress(progress, 256);
+	stop_progress(&progress);
+}
+
+static int fsck_head_link(const char *head_ref_name,
+			  const char **head_points_at,
+			  struct object_id *head_oid)
+{
+	int null_is_error = 0;
+
+	if (verbose)
+		fprintf_ln(stderr, _("Checking %s link"), head_ref_name);
+
+	*head_points_at = resolve_ref_unsafe(head_ref_name, 0, head_oid, NULL);
+	if (!*head_points_at) {
+		errors_found |= ERROR_REFS;
+		return error(_("invalid %s"), head_ref_name);
+	}
+	if (!strcmp(*head_points_at, head_ref_name))
+		/* detached HEAD */
+		null_is_error = 1;
+	else if (!starts_with(*head_points_at, "refs/heads/")) {
+		errors_found |= ERROR_REFS;
+		return error(_("%s points to something strange (%s)"),
+			     head_ref_name, *head_points_at);
+	}
+	if (is_null_oid(head_oid)) {
+		if (null_is_error) {
+			errors_found |= ERROR_REFS;
+			return error(_("%s: detached HEAD points at nothing"),
+				     head_ref_name);
+		}
+		fprintf_ln(stderr,
+			   _("notice: %s points to an unborn branch (%s)"),
+			   head_ref_name, *head_points_at + 11);
+	}
+	return 0;
+}
+
+static int fsck_cache_tree(struct cache_tree *it)
+{
+	int i;
+	int err = 0;
+
+	if (verbose)
+		fprintf_ln(stderr, _("Checking cache tree"));
+
+	if (0 <= it->entry_count) {
+		struct object *obj = parse_object(the_repository, &it->oid);
+		if (!obj) {
+			error(_("%s: invalid sha1 pointer in cache-tree"),
+			      oid_to_hex(&it->oid));
+			errors_found |= ERROR_REFS;
+			return 1;
+		}
+		obj->flags |= USED;
+		if (name_objects)
+			add_decoration(fsck_walk_options.object_names,
+				obj, xstrdup(":"));
+		mark_object_reachable(obj);
+		if (obj->type != OBJ_TREE)
+			err |= objerror(obj, _("non-tree in cache-tree"));
+	}
+	for (i = 0; i < it->subtree_nr; i++)
+		err |= fsck_cache_tree(it->down[i]->cache_tree);
+	return err;
+}
+
+static void mark_object_for_connectivity(const struct object_id *oid)
+{
+	struct object *obj = lookup_unknown_object(oid);
+	obj->flags |= HAS_OBJ;
+}
+
+static int mark_loose_for_connectivity(const struct object_id *oid,
+				       const char *path,
+				       void *data)
+{
+	mark_object_for_connectivity(oid);
+	return 0;
+}
+
+static int mark_packed_for_connectivity(const struct object_id *oid,
+					struct packed_git *pack,
+					uint32_t pos,
+					void *data)
+{
+	mark_object_for_connectivity(oid);
+	return 0;
+}
+
+static char const * const fsck_usage[] = {
+	N_("git fsck [<options>] [<object>...]"),
+	NULL
+};
+
+static struct option fsck_opts[] = {
+	OPT__VERBOSE(&verbose, N_("be verbose")),
+	OPT_BOOL(0, "unreachable", &show_unreachable, N_("show unreachable objects")),
+	OPT_BOOL(0, "dangling", &show_dangling, N_("show dangling objects")),
+	OPT_BOOL(0, "tags", &show_tags, N_("report tags")),
+	OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
+	OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
+	OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
+	OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),
+	OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
+	OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
+	OPT_BOOL(0, "lost-found", &write_lost_and_found,
+				N_("write dangling objects in .git/lost-found")),
+	OPT_BOOL(0, "progress", &show_progress, N_("show progress")),
+	OPT_BOOL(0, "name-objects", &name_objects, N_("show verbose names for reachable objects")),
+	OPT_END(),
+};
+
+int cmd_fsck(int argc, const char **argv, const char *prefix)
+{
+	int i;
+	struct object_directory *odb;
+
+	/* fsck knows how to handle missing promisor objects */
+	fetch_if_missing = 0;
+
+	errors_found = 0;
+	read_replace_refs = 0;
+
+	argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
+
+	fsck_walk_options.walk = mark_object;
+	fsck_obj_options.walk = mark_used;
+	fsck_obj_options.error_func = fsck_error_func;
+	if (check_strict)
+		fsck_obj_options.strict = 1;
+
+	if (show_progress == -1)
+		show_progress = isatty(2);
+	if (verbose)
+		show_progress = 0;
+
+	if (write_lost_and_found) {
+		check_full = 1;
+		include_reflogs = 0;
+	}
+
+	if (name_objects)
+		fsck_walk_options.object_names =
+			xcalloc(1, sizeof(struct decoration));
+
+	git_config(fsck_config, NULL);
+
+	if (connectivity_only) {
+		for_each_loose_object(mark_loose_for_connectivity, NULL, 0);
+		for_each_packed_object(mark_packed_for_connectivity, NULL, 0);
+	} else {
+		prepare_alt_odb(the_repository);
+		for (odb = the_repository->objects->odb; odb; odb = odb->next)
+			fsck_object_dir(odb->path);
+
+		if (check_full) {
+			struct packed_git *p;
+			uint32_t total = 0, count = 0;
+			struct progress *progress = NULL;
+
+			if (show_progress) {
+				for (p = get_all_packs(the_repository); p;
+				     p = p->next) {
+					if (open_pack_index(p))
+						continue;
+					total += p->num_objects;
+				}
+
+				progress = start_progress(_("Checking objects"), total);
+			}
+			for (p = get_all_packs(the_repository); p;
+			     p = p->next) {
+				/* verify gives error messages itself */
+				if (verify_pack(the_repository,
+						p, fsck_obj_buffer,
+						progress, count))
+					errors_found |= ERROR_PACK;
+				count += p->num_objects;
+			}
+			stop_progress(&progress);
+		}
+
+		if (fsck_finish(&fsck_obj_options))
+			errors_found |= ERROR_OBJECT;
+	}
+
+	for (i = 0; i < argc; i++) {
+		const char *arg = argv[i];
+		struct object_id oid;
+		if (!get_oid(arg, &oid)) {
+			struct object *obj = lookup_object(the_repository,
+							   &oid);
+
+			if (!obj || !(obj->flags & HAS_OBJ)) {
+				if (is_promisor_object(&oid))
+					continue;
+				error(_("%s: object missing"), oid_to_hex(&oid));
+				errors_found |= ERROR_OBJECT;
+				continue;
+			}
+
+			obj->flags |= USED;
+			if (name_objects)
+				add_decoration(fsck_walk_options.object_names,
+					obj, xstrdup(arg));
+			mark_object_reachable(obj);
+			continue;
+		}
+		error(_("invalid parameter: expected sha1, got '%s'"), arg);
+		errors_found |= ERROR_OBJECT;
+	}
+
+	/*
+	 * If we've not been given any explicit head information, do the
+	 * default ones from .git/refs. We also consider the index file
+	 * in this case (ie this implies --cache).
+	 */
+	if (!argc) {
+		get_default_heads();
+		keep_cache_objects = 1;
+	}
+
+	if (keep_cache_objects) {
+		verify_index_checksum = 1;
+		verify_ce_order = 1;
+		read_cache();
+		for (i = 0; i < active_nr; i++) {
+			unsigned int mode;
+			struct blob *blob;
+			struct object *obj;
+
+			mode = active_cache[i]->ce_mode;
+			if (S_ISGITLINK(mode))
+				continue;
+			blob = lookup_blob(the_repository,
+					   &active_cache[i]->oid);
+			if (!blob)
+				continue;
+			obj = &blob->object;
+			obj->flags |= USED;
+			if (name_objects)
+				add_decoration(fsck_walk_options.object_names,
+					obj,
+					xstrfmt(":%s", active_cache[i]->name));
+			mark_object_reachable(obj);
+		}
+		if (active_cache_tree)
+			fsck_cache_tree(active_cache_tree);
+	}
+
+	check_connectivity();
+
+	if (!git_config_get_bool("core.commitgraph", &i) && i) {
+		struct child_process commit_graph_verify = CHILD_PROCESS_INIT;
+		const char *verify_argv[] = { "commit-graph", "verify", NULL, NULL, NULL };
+
+		prepare_alt_odb(the_repository);
+		for (odb = the_repository->objects->odb; odb; odb = odb->next) {
+			child_process_init(&commit_graph_verify);
+			commit_graph_verify.argv = verify_argv;
+			commit_graph_verify.git_cmd = 1;
+			verify_argv[2] = "--object-dir";
+			verify_argv[3] = odb->path;
+			if (run_command(&commit_graph_verify))
+				errors_found |= ERROR_COMMIT_GRAPH;
+		}
+	}
+
+	if (!git_config_get_bool("core.multipackindex", &i) && i) {
+		struct child_process midx_verify = CHILD_PROCESS_INIT;
+		const char *midx_argv[] = { "multi-pack-index", "verify", NULL, NULL, NULL };
+
+		prepare_alt_odb(the_repository);
+		for (odb = the_repository->objects->odb; odb; odb = odb->next) {
+			child_process_init(&midx_verify);
+			midx_verify.argv = midx_argv;
+			midx_verify.git_cmd = 1;
+			midx_argv[2] = "--object-dir";
+			midx_argv[3] = odb->path;
+			if (run_command(&midx_verify))
+				errors_found |= ERROR_COMMIT_GRAPH;
+		}
+	}
+
+	return errors_found;
+}