/*
 * "git fetch"
 */

#define USE_THE_REPOSITORY_VARIABLE
#define DISABLE_SIGN_COMPARE_WARNINGS

#include "builtin.h"
#include "advice.h"
#include "config.h"
#include "gettext.h"
#include "environment.h"
#include "hex.h"
#include "refs.h"
#include "refspec.h"
#include "object-name.h"
#include "odb.h"
#include "oidset.h"
#include "oid-array.h"
#include "commit.h"
#include "string-list.h"
#include "remote.h"
#include "transport.h"
#include "run-command.h"
#include "parse-options.h"
#include "sigchain.h"
#include "submodule-config.h"
#include "submodule.h"
#include "connected.h"
#include "strvec.h"
#include "utf8.h"
#include "pager.h"
#include "path.h"
#include "pkt-line.h"
#include "list-objects-filter-options.h"
#include "commit-reach.h"
#include "branch.h"
#include "promisor-remote.h"
#include "commit-graph.h"
#include "shallow.h"
#include "trace.h"
#include "trace2.h"
#include "bundle-uri.h"

#define FORCED_UPDATES_DELAY_WARNING_IN_MS (10 * 1000)

static const char * const builtin_fetch_usage[] = {
	N_("git fetch [<options>] [<repository> [<refspec>...]]"),
	N_("git fetch [<options>] <group>"),
	N_("git fetch --multiple [<options>] [(<repository>|<group>)...]"),
	N_("git fetch --all [<options>]"),
	NULL
};

enum {
	TAGS_UNSET = 0,
	TAGS_DEFAULT = 1,
	TAGS_SET = 2
};

enum display_format {
	DISPLAY_FORMAT_FULL,
	DISPLAY_FORMAT_COMPACT,
	DISPLAY_FORMAT_PORCELAIN,
};

struct display_state {
	struct strbuf buf;

	int refcol_width;
	enum display_format format;

	char *url;
	int url_len, shown_url;
};

static uint64_t forced_updates_ms = 0;
static int prefetch = 0;
static int prune = -1; /* unspecified */
#define PRUNE_BY_DEFAULT 0 /* do we prune by default? */

static int prune_tags = -1; /* unspecified */
#define PRUNE_TAGS_BY_DEFAULT 0 /* do we prune tags by default? */

static int append, dry_run, force, keep, update_head_ok;
static int write_fetch_head = 1;
static int verbosity, deepen_relative, set_upstream, refetch;
static int progress = -1;
static int tags = TAGS_DEFAULT, update_shallow, deepen;
static int atomic_fetch;
static enum transport_family family;
static const char *depth;
static const char *deepen_since;
static const char *upload_pack;
static struct string_list deepen_not = STRING_LIST_INIT_NODUP;
static struct strbuf default_rla = STRBUF_INIT;
static struct transport *gtransport;
static struct transport *gsecondary;
static struct refspec refmap;
static struct string_list server_options = STRING_LIST_INIT_DUP;
static struct string_list negotiation_restrict = STRING_LIST_INIT_NODUP;
static struct string_list negotiation_include = STRING_LIST_INIT_NODUP;

struct fetch_config {
	enum display_format display_format;
	enum follow_remote_head_settings follow_remote_head;
	int all;
	int prune;
	int prune_tags;
	int show_forced_updates;
	int recurse_submodules;
	int parallel;
	int submodule_fetch_jobs;
};

static int git_fetch_config(const char *k, const char *v,
			    const struct config_context *ctx, void *cb)
{
	struct fetch_config *fetch_config = cb;

	if (!strcmp(k, "fetch.all")) {
		fetch_config->all = git_config_bool(k, v);
		return 0;
	}

	if (!strcmp(k, "fetch.prune")) {
		fetch_config->prune = git_config_bool(k, v);
		return 0;
	}

	if (!strcmp(k, "fetch.prunetags")) {
		fetch_config->prune_tags = git_config_bool(k, v);
		return 0;
	}

	if (!strcmp(k, "fetch.showforcedupdates")) {
		fetch_config->show_forced_updates = git_config_bool(k, v);
		return 0;
	}

	if (!strcmp(k, "submodule.recurse")) {
		int r = git_config_bool(k, v) ?
			RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
		fetch_config->recurse_submodules = r;
		return 0;
	}

	if (!strcmp(k, "submodule.fetchjobs")) {
		fetch_config->submodule_fetch_jobs = parse_submodule_fetchjobs(k, v, ctx->kvi);
		return 0;
	} else if (!strcmp(k, "fetch.recursesubmodules")) {
		fetch_config->recurse_submodules = parse_fetch_recurse_submodules_arg(k, v);
		return 0;
	}

	if (!strcmp(k, "fetch.parallel")) {
		fetch_config->parallel = git_config_int(k, v, ctx->kvi);
		if (fetch_config->parallel < 0)
			die(_("fetch.parallel cannot be negative"));
		if (!fetch_config->parallel)
			fetch_config->parallel = online_cpus();
		return 0;
	}

	if (!strcmp(k, "fetch.output")) {
		if (!v)
			return config_error_nonbool(k);
		else if (!strcasecmp(v, "full"))
			fetch_config->display_format = DISPLAY_FORMAT_FULL;
		else if (!strcasecmp(v, "compact"))
			fetch_config->display_format = DISPLAY_FORMAT_COMPACT;
		else
			die(_("invalid value for '%s': '%s'"),
			    "fetch.output", v);
		return 0;
	}

	if (!strcmp(k, "fetch.followremotehead")) {
		if (!v)
			return config_error_nonbool(k);
		else if (!strcmp(v, "never"))
			fetch_config->follow_remote_head = FOLLOW_REMOTE_NEVER;
		else if (!strcmp(v, "create"))
			fetch_config->follow_remote_head = FOLLOW_REMOTE_CREATE;
		else if (!strcmp(v, "warn"))
			fetch_config->follow_remote_head = FOLLOW_REMOTE_WARN;
		else if (!strcmp(v, "always"))
			fetch_config->follow_remote_head = FOLLOW_REMOTE_ALWAYS;
		else
			warning(_("unrecognized fetch.followRemoteHEAD value '%s' ignored"), v);
		return 0;
	}

	return git_default_config(k, v, ctx, cb);
}

static int parse_refmap_arg(const struct option *opt, const char *arg, int unset)
{
	BUG_ON_OPT_NEG(unset);

	/*
	 * "git fetch --refmap='' origin foo"
	 * can be used to tell the command not to store anywhere
	 */
	refspec_append(opt->value, arg);

	return 0;
}

static void unlock_pack(unsigned int flags)
{
	if (gtransport)
		transport_unlock_pack(gtransport, flags);
	if (gsecondary)
		transport_unlock_pack(gsecondary, flags);
}

static void unlock_pack_atexit(void)
{
	unlock_pack(0);
}

static void unlock_pack_on_signal(int signo)
{
	unlock_pack(TRANSPORT_UNLOCK_PACK_IN_SIGNAL_HANDLER);
	sigchain_pop(signo);
	raise(signo);
}

static void add_merge_config(struct ref **head,
			   const struct ref *remote_refs,
		           struct branch *branch,
		           struct ref ***tail)
{
	int i;

	for (i = 0; i < branch->merge_nr; i++) {
		struct ref *rm, **old_tail = *tail;
		struct refspec_item refspec;

		for (rm = *head; rm; rm = rm->next) {
			if (branch_merge_matches(branch, i, rm->name)) {
				rm->fetch_head_status = FETCH_HEAD_MERGE;
				break;
			}
		}
		if (rm)
			continue;

		/*
		 * Not fetched to a remote-tracking branch?  We need to fetch
		 * it anyway to allow this branch's "branch.$name.merge"
		 * to be honored by 'git pull', but we do not have to
		 * fail if branch.$name.merge is misconfigured to point
		 * at a nonexisting branch.  If we were indeed called by
		 * 'git pull', it will notice the misconfiguration because
		 * there is no entry in the resulting FETCH_HEAD marked
		 * for merging.
		 */
		memset(&refspec, 0, sizeof(refspec));
		refspec.src = branch->merge[i]->src;
		get_fetch_map(remote_refs, &refspec, tail, 1);
		for (rm = *old_tail; rm; rm = rm->next)
			rm->fetch_head_status = FETCH_HEAD_MERGE;
	}
}

static void create_fetch_oidset(struct ref **head, struct oidset *out)
{
	struct ref *rm = *head;
	while (rm) {
		oidset_insert(out, &rm->old_oid);
		rm = rm->next;
	}
}

struct refname_hash_entry {
	struct hashmap_entry ent;
	struct object_id oid;
	int ignore;
	char refname[FLEX_ARRAY];
};

static int refname_hash_entry_cmp(const void *hashmap_cmp_fn_data UNUSED,
				  const struct hashmap_entry *eptr,
				  const struct hashmap_entry *entry_or_key,
				  const void *keydata)
{
	const struct refname_hash_entry *e1, *e2;

	e1 = container_of(eptr, const struct refname_hash_entry, ent);
	e2 = container_of(entry_or_key, const struct refname_hash_entry, ent);
	return strcmp(e1->refname, keydata ? keydata : e2->refname);
}

static struct refname_hash_entry *refname_hash_add(struct hashmap *map,
						   const char *refname,
						   const struct object_id *oid)
{
	struct refname_hash_entry *ent;
	size_t len = strlen(refname);

	FLEX_ALLOC_MEM(ent, refname, refname, len);
	hashmap_entry_init(&ent->ent, strhash(refname));
	oidcpy(&ent->oid, oid);
	hashmap_add(map, &ent->ent);
	return ent;
}

static int add_one_refname(const struct reference *ref, void *cbdata)
{
	struct hashmap *refname_map = cbdata;

	(void) refname_hash_add(refname_map, ref->name, ref->oid);
	return 0;
}

static void refname_hash_init(struct hashmap *map)
{
	hashmap_init(map, refname_hash_entry_cmp, NULL, 0);
}

static int refname_hash_exists(struct hashmap *map, const char *refname)
{
	return !!hashmap_get_from_hash(map, strhash(refname), refname);
}

static void clear_item(struct refname_hash_entry *item)
{
	item->ignore = 1;
}


static void add_already_queued_tags(const char *refname,
				    const struct object_id *old_oid UNUSED,
				    const struct object_id *new_oid,
				    void *cb_data)
{
	struct hashmap *queued_tags = cb_data;
	if (starts_with(refname, "refs/tags/") && new_oid)
		(void) refname_hash_add(queued_tags, refname, new_oid);
}

static void find_non_local_tags(const struct ref *refs,
				struct ref_transaction *transaction,
				struct ref **head,
				struct ref ***tail)
{
	struct hashmap existing_refs;
	struct hashmap remote_refs;
	struct oidset fetch_oids = OIDSET_INIT;
	struct string_list remote_refs_list = STRING_LIST_INIT_NODUP;
	struct string_list_item *remote_ref_item;
	const struct ref *ref;
	struct refname_hash_entry *item = NULL;

	refname_hash_init(&existing_refs);
	refname_hash_init(&remote_refs);
	create_fetch_oidset(head, &fetch_oids);

	refs_for_each_ref(get_main_ref_store(the_repository), add_one_refname,
			  &existing_refs);

	/*
	 * If we already have a transaction, then we need to filter out all
	 * tags which have already been queued up.
	 */
	if (transaction)
		ref_transaction_for_each_queued_update(transaction,
						       add_already_queued_tags,
						       &existing_refs);

	for (ref = refs; ref; ref = ref->next) {
		if (!starts_with(ref->name, "refs/tags/"))
			continue;

		/*
		 * The peeled ref always follows the matching base
		 * ref, so if we see a peeled ref that we don't want
		 * to fetch then we can mark the ref entry in the list
		 * as one to ignore by setting util to NULL.
		 */
		if (ends_with(ref->name, "^{}")) {
			if (item &&
			    !odb_has_object(the_repository->objects, &ref->old_oid, 0) &&
			    !oidset_contains(&fetch_oids, &ref->old_oid) &&
			    !odb_has_object(the_repository->objects, &item->oid, 0) &&
			    !oidset_contains(&fetch_oids, &item->oid))
				clear_item(item);
			item = NULL;
			continue;
		}

		/*
		 * If item is non-NULL here, then we previously saw a
		 * ref not followed by a peeled reference, so we need
		 * to check if it is a lightweight tag that we want to
		 * fetch.
		 */
		if (item &&
		    !odb_has_object(the_repository->objects, &item->oid, 0) &&
		    !oidset_contains(&fetch_oids, &item->oid))
			clear_item(item);

		item = NULL;

		/* skip duplicates and refs that we already have */
		if (refname_hash_exists(&remote_refs, ref->name) ||
		    refname_hash_exists(&existing_refs, ref->name))
			continue;

		item = refname_hash_add(&remote_refs, ref->name, &ref->old_oid);
		string_list_insert(&remote_refs_list, ref->name);
	}
	hashmap_clear_and_free(&existing_refs, struct refname_hash_entry, ent);

	/*
	 * We may have a final lightweight tag that needs to be
	 * checked to see if it needs fetching.
	 */
	if (item &&
	    !odb_has_object(the_repository->objects, &item->oid, 0) &&
	    !oidset_contains(&fetch_oids, &item->oid))
		clear_item(item);

	/*
	 * For all the tags in the remote_refs_list,
	 * add them to the list of refs to be fetched
	 */
	for_each_string_list_item(remote_ref_item, &remote_refs_list) {
		const char *refname = remote_ref_item->string;
		struct ref *rm;
		unsigned int hash = strhash(refname);

		item = hashmap_get_entry_from_hash(&remote_refs, hash, refname,
					struct refname_hash_entry, ent);
		if (!item)
			BUG("unseen remote ref?");

		/* Unless we have already decided to ignore this item... */
		if (item->ignore)
			continue;

		rm = alloc_ref(item->refname);
		rm->peer_ref = alloc_ref(item->refname);
		oidcpy(&rm->old_oid, &item->oid);
		**tail = rm;
		*tail = &rm->next;
	}
	hashmap_clear_and_free(&remote_refs, struct refname_hash_entry, ent);
	string_list_clear(&remote_refs_list, 0);
	oidset_clear(&fetch_oids);
}

static void filter_prefetch_refspec(struct refspec *rs)
{
	int i;

	if (!prefetch)
		return;

	for (i = 0; i < rs->nr; i++) {
		struct strbuf new_dst = STRBUF_INIT;
		char *old_dst;
		const char *sub = NULL;

		if (rs->items[i].negative)
			continue;
		if (!rs->items[i].dst ||
		    (rs->items[i].src &&
		     starts_with(rs->items[i].src,
				 ref_namespace[NAMESPACE_TAGS].ref))) {
			int j;

			refspec_item_clear(&rs->items[i]);

			for (j = i + 1; j < rs->nr; j++)
				rs->items[j - 1] = rs->items[j];
			rs->nr--;
			i--;
			continue;
		}

		old_dst = rs->items[i].dst;
		strbuf_addstr(&new_dst, ref_namespace[NAMESPACE_PREFETCH].ref);

		/*
		 * If old_dst starts with "refs/", then place
		 * sub after that prefix. Otherwise, start at
		 * the beginning of the string.
		 */
		if (!skip_prefix(old_dst, "refs/", &sub))
			sub = old_dst;
		strbuf_addstr(&new_dst, sub);

		rs->items[i].dst = strbuf_detach(&new_dst, NULL);
		rs->items[i].force = 1;

		free(old_dst);
	}
}

static struct ref *get_ref_map(struct remote *remote,
			       const struct ref *remote_refs,
			       struct refspec *rs,
			       int tags, int *autotags)
{
	int i;
	struct ref *rm;
	struct ref *ref_map = NULL;
	struct ref **tail = &ref_map;

	/* opportunistically-updated references: */
	struct ref *orefs = NULL, **oref_tail = &orefs;

	struct hashmap existing_refs;
	int existing_refs_populated = 0;

	filter_prefetch_refspec(rs);
	if (remote)
		filter_prefetch_refspec(&remote->fetch);

	if (rs->nr) {
		struct refspec *fetch_refspec;

		for (i = 0; i < rs->nr; i++) {
			get_fetch_map(remote_refs, &rs->items[i], &tail, 0);
			if (rs->items[i].dst && rs->items[i].dst[0])
				*autotags = 1;
		}
		/* Merge everything on the command line (but not --tags) */
		for (rm = ref_map; rm; rm = rm->next)
			rm->fetch_head_status = FETCH_HEAD_MERGE;

		/*
		 * For any refs that we happen to be fetching via
		 * command-line arguments, the destination ref might
		 * have been missing or have been different than the
		 * remote-tracking ref that would be derived from the
		 * configured refspec.  In these cases, we want to
		 * take the opportunity to update their configured
		 * remote-tracking reference.  However, we do not want
		 * to mention these entries in FETCH_HEAD at all, as
		 * they would simply be duplicates of existing
		 * entries, so we set them FETCH_HEAD_IGNORE below.
		 *
		 * We compute these entries now, based only on the
		 * refspecs specified on the command line.  But we add
		 * them to the list following the refspecs resulting
		 * from the tags option so that one of the latter,
		 * which has FETCH_HEAD_NOT_FOR_MERGE, is not removed
		 * by ref_remove_duplicates() in favor of one of these
		 * opportunistic entries with FETCH_HEAD_IGNORE.
		 */
		if (refmap.nr)
			fetch_refspec = &refmap;
		else
			fetch_refspec = &remote->fetch;

		for (i = 0; i < fetch_refspec->nr; i++)
			get_fetch_map(ref_map, &fetch_refspec->items[i], &oref_tail, 1);
	} else if (refmap.nr) {
		die("--refmap option is only meaningful with command-line refspec(s)");
	} else {
		/* Use the defaults */
		struct branch *branch = branch_get(NULL);
		int has_merge = branch_has_merge_config(branch);
		if (remote &&
		    (remote->fetch.nr ||
		     /* Note: has_merge implies non-NULL branch->remote_name */
		     (has_merge && !strcmp(branch->remote_name, remote->name)))) {
			for (i = 0; i < remote->fetch.nr; i++) {
				get_fetch_map(remote_refs, &remote->fetch.items[i], &tail, 0);
				if (remote->fetch.items[i].dst &&
				    remote->fetch.items[i].dst[0])
					*autotags = 1;
				if (!i && !has_merge && ref_map &&
				    !remote->fetch.items[0].pattern)
					ref_map->fetch_head_status = FETCH_HEAD_MERGE;
			}
			/*
			 * if the remote we're fetching from is the same
			 * as given in branch.<name>.remote, we add the
			 * ref given in branch.<name>.merge, too.
			 *
			 * Note: has_merge implies non-NULL branch->remote_name
			 */
			if (has_merge &&
			    !strcmp(branch->remote_name, remote->name))
				add_merge_config(&ref_map, remote_refs, branch, &tail);
		} else if (!prefetch) {
			ref_map = get_remote_ref(remote_refs, "HEAD");
			if (!ref_map)
				die(_("couldn't find remote ref HEAD"));
			ref_map->fetch_head_status = FETCH_HEAD_MERGE;
			tail = &ref_map->next;
		}
	}

	if (tags == TAGS_SET) {
		struct refspec_item tag_refspec;

		/* also fetch all tags */
		refspec_item_init_push(&tag_refspec, TAG_REFSPEC,
				       the_hash_algo);
		get_fetch_map(remote_refs, &tag_refspec, &tail, 0);
		refspec_item_clear(&tag_refspec);
	} else if (tags == TAGS_DEFAULT && *autotags) {
		find_non_local_tags(remote_refs, NULL, &ref_map, &tail);
	}

	/* Now append any refs to be updated opportunistically: */
	*tail = orefs;
	for (rm = orefs; rm; rm = rm->next) {
		rm->fetch_head_status = FETCH_HEAD_IGNORE;
		tail = &rm->next;
	}

	/*
	 * apply negative refspecs first, before we remove duplicates. This is
	 * necessary as negative refspecs might remove an otherwise conflicting
	 * duplicate.
	 */
	if (rs->nr)
		ref_map = apply_negative_refspecs(ref_map, rs);
	else
		ref_map = apply_negative_refspecs(ref_map, &remote->fetch);

	ref_map = ref_remove_duplicates(ref_map);

	for (rm = ref_map; rm; rm = rm->next) {
		if (rm->peer_ref) {
			const char *refname = rm->peer_ref->name;
			struct refname_hash_entry *peer_item;
			unsigned int hash = strhash(refname);

			if (!existing_refs_populated) {
				refname_hash_init(&existing_refs);
				refs_for_each_ref(get_main_ref_store(the_repository),
						  add_one_refname,
						  &existing_refs);
				existing_refs_populated = 1;
			}

			peer_item = hashmap_get_entry_from_hash(&existing_refs,
						hash, refname,
						struct refname_hash_entry, ent);
			if (peer_item) {
				struct object_id *old_oid = &peer_item->oid;
				oidcpy(&rm->peer_ref->old_oid, old_oid);
			}
		}
	}
	if (existing_refs_populated)
		hashmap_clear_and_free(&existing_refs, struct refname_hash_entry, ent);

	return ref_map;
}

static int s_update_ref(const char *action,
			struct ref *ref,
			struct ref_transaction *transaction,
			int check_old)
{
	char *msg;
	char *rla = getenv("GIT_REFLOG_ACTION");
	struct strbuf err = STRBUF_INIT;
	int ret;

	if (dry_run)
		return 0;
	if (!rla)
		rla = default_rla.buf;
	msg = xstrfmt("%s: %s", rla, action);

	ret = ref_transaction_update(transaction, ref->name, &ref->new_oid,
				     check_old ? &ref->old_oid : NULL,
				     NULL, NULL, 0, msg, &err);

	if (ret)
		error("%s", err.buf);
	strbuf_release(&err);
	free(msg);
	return ret;
}

static int refcol_width(const struct ref *ref_map, int compact_format)
{
	const struct ref *ref;
	int max, width = 10;

	max = term_columns();
	if (compact_format)
		max = max * 2 / 3;

	for (ref = ref_map; ref; ref = ref->next) {
		int rlen, llen = 0, len;

		if (ref->status == REF_STATUS_REJECT_SHALLOW ||
		    !ref->peer_ref ||
		    !strcmp(ref->name, "HEAD"))
			continue;

		/* uptodate lines are only shown on high verbosity level */
		if (verbosity <= 0 && oideq(&ref->peer_ref->old_oid, &ref->old_oid))
			continue;

		rlen = utf8_strwidth(prettify_refname(ref->name));
		if (!compact_format)
			llen = utf8_strwidth(prettify_refname(ref->peer_ref->name));

		/*
		 * rough estimation to see if the output line is too long and
		 * should not be counted (we can't do precise calculation
		 * anyway because we don't know if the error explanation part
		 * will be printed in update_local_ref)
		 */
		len = 21 /* flag and summary */ + rlen + 4 /* -> */ + llen;
		if (len >= max)
			continue;

		if (width < rlen)
			width = rlen;
	}

	return width;
}

static void display_state_init(struct display_state *display_state, struct ref *ref_map,
			       const char *raw_url, enum display_format format)
{
	int i;

	memset(display_state, 0, sizeof(*display_state));
	strbuf_init(&display_state->buf, 0);
	display_state->format = format;

	if (raw_url)
		display_state->url = transport_anonymize_url(raw_url);
	else
		display_state->url = xstrdup("foreign");

	display_state->url_len = strlen(display_state->url);
	for (i = display_state->url_len - 1; 0 <= i && display_state->url[i] == '/'; i--)
		;
	display_state->url_len = i + 1;
	if (4 < i && !strncmp(".git", display_state->url + i - 3, 4))
		display_state->url_len = i - 3;

	if (verbosity < 0)
		return;

	switch (display_state->format) {
	case DISPLAY_FORMAT_FULL:
	case DISPLAY_FORMAT_COMPACT:
		display_state->refcol_width = refcol_width(ref_map,
							   display_state->format == DISPLAY_FORMAT_COMPACT);
		break;
	case DISPLAY_FORMAT_PORCELAIN:
		/* We don't need to precompute anything here. */
		break;
	default:
		BUG("unexpected display format %d", display_state->format);
	}
}

static void display_state_release(struct display_state *display_state)
{
	strbuf_release(&display_state->buf);
	free(display_state->url);
}

static void print_remote_to_local(struct display_state *display_state,
				  const char *remote, const char *local)
{
	strbuf_addf(&display_state->buf, "%-*s -> %s",
		    display_state->refcol_width, remote, local);
}

static int find_and_replace(struct strbuf *haystack,
			    const char *needle,
			    const char *placeholder)
{
	const char *p = NULL;
	int plen, nlen;

	nlen = strlen(needle);
	if (ends_with(haystack->buf, needle))
		p = haystack->buf + haystack->len - nlen;
	else
		p = strstr(haystack->buf, needle);
	if (!p)
		return 0;

	if (p > haystack->buf && p[-1] != '/')
		return 0;

	plen = strlen(p);
	if (plen > nlen && p[nlen] != '/')
		return 0;

	strbuf_splice(haystack, p - haystack->buf, nlen,
		      placeholder, strlen(placeholder));
	return 1;
}

static void print_compact(struct display_state *display_state,
			  const char *remote, const char *local)
{
	struct strbuf r = STRBUF_INIT;
	struct strbuf l = STRBUF_INIT;

	if (!strcmp(remote, local)) {
		strbuf_addf(&display_state->buf, "%-*s -> *", display_state->refcol_width, remote);
		return;
	}

	strbuf_addstr(&r, remote);
	strbuf_addstr(&l, local);

	if (!find_and_replace(&r, local, "*"))
		find_and_replace(&l, remote, "*");
	print_remote_to_local(display_state, r.buf, l.buf);

	strbuf_release(&r);
	strbuf_release(&l);
}

static void display_ref_update(struct display_state *display_state, char code,
			       const char *summary, const char *error,
			       const char *remote, const char *local,
			       const struct object_id *old_oid,
			       const struct object_id *new_oid,
			       int summary_width)
{
	FILE *f = stderr;

	if (verbosity < 0)
		return;

	strbuf_reset(&display_state->buf);

	switch (display_state->format) {
	case DISPLAY_FORMAT_FULL:
	case DISPLAY_FORMAT_COMPACT: {
		int width;

		if (!display_state->shown_url) {
			strbuf_addf(&display_state->buf, _("From %.*s\n"),
				    display_state->url_len, display_state->url);
			display_state->shown_url = 1;
		}

		width = (summary_width + strlen(summary) - gettext_width(summary));
		remote = prettify_refname(remote);
		local = prettify_refname(local);

		strbuf_addf(&display_state->buf, " %c %-*s ", code, width, summary);

		if (display_state->format != DISPLAY_FORMAT_COMPACT)
			print_remote_to_local(display_state, remote, local);
		else
			print_compact(display_state, remote, local);

		if (error)
			strbuf_addf(&display_state->buf, "  (%s)", error);

		break;
	}
	case DISPLAY_FORMAT_PORCELAIN:
		strbuf_addf(&display_state->buf, "%c %s %s %s", code,
			    oid_to_hex(old_oid), oid_to_hex(new_oid), local);
		f = stdout;
		break;
	default:
		BUG("unexpected display format %d", display_state->format);
	};
	strbuf_addch(&display_state->buf, '\n');

	fputs(display_state->buf.buf, f);
}

struct ref_update_display_info {
	bool failed;
	char success_code;
	char fail_code;
	char *summary;
	char *fail_detail;
	char *success_detail;
	char *ref;
	char *remote;
	struct object_id old_oid;
	struct object_id new_oid;
};

struct ref_update_display_info_array {
	struct ref_update_display_info *info;
	size_t alloc, nr;
};

static struct ref_update_display_info *ref_update_display_info_append(
					   struct ref_update_display_info_array *array,
					   char success_code,
					   char fail_code,
					   const char *summary,
					   const char *success_detail,
					   const char *fail_detail,
					   const char *ref,
					   const char *remote,
					   const struct object_id *old_oid,
					   const struct object_id *new_oid)
{
	struct ref_update_display_info *info;

	ALLOC_GROW(array->info, array->nr + 1, array->alloc);
	info = &array->info[array->nr++];

	info->failed = false;
	info->success_code = success_code;
	info->fail_code = fail_code;
	info->summary = xstrdup(summary);
	info->success_detail = xstrdup_or_null(success_detail);
	info->fail_detail = xstrdup_or_null(fail_detail);
	info->remote = xstrdup(remote);
	info->ref = xstrdup(ref);

	oidcpy(&info->old_oid, old_oid);
	oidcpy(&info->new_oid, new_oid);

	return info;
}

static void ref_update_display_info_set_failed(struct ref_update_display_info *info)
{
	info->failed = true;
}

static void ref_update_display_info_free(struct ref_update_display_info *info)
{
	free(info->summary);
	free(info->success_detail);
	free(info->fail_detail);
	free(info->remote);
	free(info->ref);
}

static void ref_update_display_info_display(struct ref_update_display_info *info,
					    struct display_state *display_state,
					    int summary_width)
{
	display_ref_update(display_state,
			   info->failed ? info->fail_code : info->success_code,
			   info->summary,
			   info->failed ? info->fail_detail : info->success_detail,
			   info->remote, info->ref, &info->old_oid,
			   &info->new_oid, summary_width);
}

static int update_local_ref(struct ref *ref,
			    struct ref_transaction *transaction,
			    const struct ref *remote_ref,
			    const struct fetch_config *config,
			    struct ref_update_display_info_array *display_array)
{
	struct commit *current = NULL, *updated;
	int fast_forward = 0;

	if (!odb_has_object(the_repository->objects, &ref->new_oid,
			    ODB_HAS_OBJECT_RECHECK_PACKED | ODB_HAS_OBJECT_FETCH_PROMISOR))
		die(_("object %s not found"), oid_to_hex(&ref->new_oid));

	if (oideq(&ref->old_oid, &ref->new_oid)) {
		if (verbosity > 0)
			ref_update_display_info_append(display_array, '=', '=',
						       _("[up to date]"), NULL,
						       NULL, ref->name,
						       remote_ref->name, &ref->old_oid,
						       &ref->new_oid);
		return 0;
	}

	if (!update_head_ok &&
	    !is_null_oid(&ref->old_oid) &&
	    branch_checked_out(ref->name)) {
		struct ref_update_display_info *info;
		/*
		 * If this is the head, and it's not okay to update
		 * the head, and the old value of the head isn't empty...
		 */
		info = ref_update_display_info_append(display_array, '!', '!',
						      _("[rejected]"), NULL,
						      _("can't fetch into checked-out branch"),
						      ref->name, remote_ref->name,
						      &ref->old_oid, &ref->new_oid);
		ref_update_display_info_set_failed(info);
		return 1;
	}

	if (!is_null_oid(&ref->old_oid) &&
	    starts_with(ref->name, "refs/tags/")) {
		struct ref_update_display_info *info;

		if (force || ref->force) {
			int r;

			r = s_update_ref("updating tag", ref, transaction, 0);

			info = ref_update_display_info_append(display_array, 't', '!',
							      _("[tag update]"), NULL,
							      _("unable to update local ref"),
							      ref->name, remote_ref->name,
							      &ref->old_oid, &ref->new_oid);
			if (r)
				ref_update_display_info_set_failed(info);

			return r;
		} else {
			info = ref_update_display_info_append(display_array, '!', '!',
							      _("[rejected]"), NULL,
							      _("would clobber existing tag"),
							      ref->name, remote_ref->name,
							      &ref->old_oid, &ref->new_oid);
			ref_update_display_info_set_failed(info);
			return 1;
		}
	}

	current = lookup_commit_reference_gently(the_repository,
						 &ref->old_oid, 1);
	updated = lookup_commit_reference_gently(the_repository,
						 &ref->new_oid, 1);
	if (!current || !updated) {
		struct ref_update_display_info *info;
		const char *msg;
		const char *what;
		int r;
		/*
		 * Nicely describe the new ref we're fetching.
		 * Base this on the remote's ref name, as it's
		 * more likely to follow a standard layout.
		 */
		if (starts_with(remote_ref->name, "refs/tags/")) {
			msg = "storing tag";
			what = _("[new tag]");
		} else if (starts_with(remote_ref->name, "refs/heads/")) {
			msg = "storing head";
			what = _("[new branch]");
		} else {
			msg = "storing ref";
			what = _("[new ref]");
		}

		r = s_update_ref(msg, ref, transaction, 0);

		info = ref_update_display_info_append(display_array, '*', '!',
						      what, NULL,
						      _("unable to update local ref"),
						      ref->name, remote_ref->name,
						      &ref->old_oid, &ref->new_oid);
		if (r)
			ref_update_display_info_set_failed(info);

		return r;
	}

	if (config->show_forced_updates) {
		uint64_t t_before = getnanotime();
		fast_forward = repo_in_merge_bases(the_repository, current,
						   updated);
		if (fast_forward < 0)
			die(NULL);
		forced_updates_ms += (getnanotime() - t_before) / 1000000;
	} else {
		fast_forward = 1;
	}

	if (fast_forward) {
		struct ref_update_display_info *info;
		struct strbuf quickref = STRBUF_INIT;
		int r;

		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
		strbuf_addstr(&quickref, "..");
		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
		r = s_update_ref("fast-forward", ref, transaction, 1);

		info = ref_update_display_info_append(display_array, ' ', '!',
						      quickref.buf, NULL,
						      _("unable to update local ref"),
						      ref->name, remote_ref->name,
						      &ref->old_oid, &ref->new_oid);
		if (r)
			ref_update_display_info_set_failed(info);

		strbuf_release(&quickref);
		return r;
	} else if (force || ref->force) {
		struct ref_update_display_info *info;
		struct strbuf quickref = STRBUF_INIT;
		int r;

		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
		strbuf_addstr(&quickref, "...");
		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
		r = s_update_ref("forced-update", ref, transaction, 1);

		info = ref_update_display_info_append(display_array, '+', '!',
						      quickref.buf, _("forced update"),
						      _("unable to update local ref"),
						      ref->name, remote_ref->name,
						      &ref->old_oid, &ref->new_oid);

		if (r)
			ref_update_display_info_set_failed(info);

		strbuf_release(&quickref);
		return r;
	} else {
		struct ref_update_display_info *info;
		info = ref_update_display_info_append(display_array, '!', '!',
						      _("[rejected]"), NULL,
						      _("non-fast-forward"),
						      ref->name, remote_ref->name,
						      &ref->old_oid, &ref->new_oid);
		ref_update_display_info_set_failed(info);
		return 1;
	}
}

static const struct object_id *iterate_ref_map(void *cb_data)
{
	struct ref **rm = cb_data;
	struct ref *ref = *rm;

	while (ref && ref->status == REF_STATUS_REJECT_SHALLOW)
		ref = ref->next;
	if (!ref)
		return NULL;
	*rm = ref->next;
	return &ref->old_oid;
}

struct fetch_head {
	FILE *fp;
	struct strbuf buf;
};

static int open_fetch_head(struct fetch_head *fetch_head)
{
	const char *filename = git_path_fetch_head(the_repository);

	if (write_fetch_head) {
		fetch_head->fp = fopen(filename, "a");
		if (!fetch_head->fp)
			return error_errno(_("cannot open '%s'"), filename);
		strbuf_init(&fetch_head->buf, 0);
	} else {
		fetch_head->fp = NULL;
	}

	return 0;
}

static void append_fetch_head(struct fetch_head *fetch_head,
			      const struct object_id *old_oid,
			      enum fetch_head_status fetch_head_status,
			      const char *note,
			      const char *url, size_t url_len)
{
	char old_oid_hex[GIT_MAX_HEXSZ + 1];
	const char *merge_status_marker;
	size_t i;

	if (!fetch_head->fp)
		return;

	switch (fetch_head_status) {
	case FETCH_HEAD_NOT_FOR_MERGE:
		merge_status_marker = "not-for-merge";
		break;
	case FETCH_HEAD_MERGE:
		merge_status_marker = "";
		break;
	default:
		/* do not write anything to FETCH_HEAD */
		return;
	}

	strbuf_addf(&fetch_head->buf, "%s\t%s\t%s",
		    oid_to_hex_r(old_oid_hex, old_oid), merge_status_marker, note);
	for (i = 0; i < url_len; ++i)
		if ('\n' == url[i])
			strbuf_addstr(&fetch_head->buf, "\\n");
		else
			strbuf_addch(&fetch_head->buf, url[i]);
	strbuf_addch(&fetch_head->buf, '\n');

	/*
	 * When using an atomic fetch, we do not want to update FETCH_HEAD if
	 * any of the reference updates fails. We thus have to write all
	 * updates to a buffer first and only commit it as soon as all
	 * references have been successfully updated.
	 */
	if (!atomic_fetch) {
		strbuf_write(&fetch_head->buf, fetch_head->fp);
		strbuf_reset(&fetch_head->buf);
	}
}

static void commit_fetch_head(struct fetch_head *fetch_head)
{
	if (!fetch_head->fp || !atomic_fetch)
		return;
	strbuf_write(&fetch_head->buf, fetch_head->fp);
}

static void close_fetch_head(struct fetch_head *fetch_head)
{
	if (!fetch_head->fp)
		return;

	fclose(fetch_head->fp);
	strbuf_release(&fetch_head->buf);
}

static const char warn_show_forced_updates[] =
N_("fetch normally indicates which branches had a forced update,\n"
   "but that check has been disabled; to re-enable, use '--show-forced-updates'\n"
   "flag or run 'git config fetch.showForcedUpdates true'");
static const char warn_time_show_forced_updates[] =
N_("it took %.2f seconds to check forced updates; you can use\n"
   "'--no-show-forced-updates' or run 'git config fetch.showForcedUpdates false'\n"
   "to avoid this check\n");

static int store_updated_refs(struct display_state *display_state,
			      int connectivity_checked,
			      struct ref_transaction *transaction, struct ref *ref_map,
			      struct fetch_head *fetch_head,
			      const struct fetch_config *config,
			      struct ref_update_display_info_array *display_array)
{
	int rc = 0;
	struct strbuf note = STRBUF_INIT;
	const char *what, *kind;
	struct ref *rm;
	int want_status;

	if (!connectivity_checked) {
		struct check_connected_options opt = CHECK_CONNECTED_INIT;

		opt.exclude_hidden_refs_section = "fetch";
		rm = ref_map;
		if (check_connected(iterate_ref_map, &rm, &opt)) {
			rc = error(_("%s did not send all necessary objects"),
				   display_state->url);
			goto abort;
		}
	}

	/*
	 * We do a pass for each fetch_head_status type in their enum order, so
	 * merged entries are written before not-for-merge. That lets readers
	 * use FETCH_HEAD as a refname to refer to the ref to be merged.
	 */
	for (want_status = FETCH_HEAD_MERGE;
	     want_status <= FETCH_HEAD_IGNORE;
	     want_status++) {
		for (rm = ref_map; rm; rm = rm->next) {
			struct ref *ref = NULL;

			if (rm->status == REF_STATUS_REJECT_SHALLOW) {
				if (want_status == FETCH_HEAD_MERGE)
					warning(_("rejected %s because shallow roots are not allowed to be updated"),
						rm->peer_ref ? rm->peer_ref->name : rm->name);
				continue;
			}

			/*
			 * When writing FETCH_HEAD we need to determine whether
			 * we already have the commit or not. If not, then the
			 * reference is not for merge and needs to be written
			 * to the reflog after other commits which we already
			 * have. We're not interested in this property though
			 * in case FETCH_HEAD is not to be updated, so we can
			 * skip the classification in that case.
			 */
			if (fetch_head->fp) {
				struct commit *commit = NULL;

				/*
				 * References in "refs/tags/" are often going to point
				 * to annotated tags, which are not part of the
				 * commit-graph. We thus only try to look up refs in
				 * the graph which are not in that namespace to not
				 * regress performance in repositories with many
				 * annotated tags.
				 */
				if (!starts_with(rm->name, "refs/tags/"))
					commit = lookup_commit_in_graph(the_repository, &rm->old_oid);
				if (!commit) {
					commit = lookup_commit_reference_gently(the_repository,
										&rm->old_oid,
										1);
					if (!commit)
						rm->fetch_head_status = FETCH_HEAD_NOT_FOR_MERGE;
				}
			}

			if (rm->fetch_head_status != want_status)
				continue;

			if (rm->peer_ref) {
				ref = alloc_ref(rm->peer_ref->name);
				oidcpy(&ref->old_oid, &rm->peer_ref->old_oid);
				oidcpy(&ref->new_oid, &rm->old_oid);
				ref->force = rm->peer_ref->force;
			}

			if (config->recurse_submodules != RECURSE_SUBMODULES_OFF &&
			    (!rm->peer_ref || !oideq(&ref->old_oid, &ref->new_oid))) {
				check_for_new_submodule_commits(&rm->old_oid);
			}

			if (!strcmp(rm->name, "HEAD")) {
				kind = "";
				what = "";
			} else if (skip_prefix(rm->name, "refs/heads/", &what)) {
				kind = "branch";
			} else if (skip_prefix(rm->name, "refs/tags/", &what)) {
				kind = "tag";
			} else if (skip_prefix(rm->name, "refs/remotes/", &what)) {
				kind = "remote-tracking branch";
			} else {
				kind = "";
				what = rm->name;
			}

			strbuf_reset(&note);
			if (*what) {
				if (*kind)
					strbuf_addf(&note, "%s ", kind);
				strbuf_addf(&note, "'%s' of ", what);
			}

			append_fetch_head(fetch_head, &rm->old_oid,
					  rm->fetch_head_status,
					  note.buf, display_state->url,
					  display_state->url_len);

			if (ref) {
				rc |= update_local_ref(ref, transaction, rm,
						       config, display_array);
				free(ref);
			} else if (write_fetch_head || dry_run) {
				/*
				 * Display fetches written to FETCH_HEAD (or
				 * would be written to FETCH_HEAD, if --dry-run
				 * is set).
				 */

				ref_update_display_info_append(display_array, '*', '*',
							       *kind ? kind : "branch",
							       NULL, NULL, "FETCH_HEAD",
							       rm->name, &rm->new_oid,
							       &rm->old_oid);
			}
		}
	}

	if (advice_enabled(ADVICE_FETCH_SHOW_FORCED_UPDATES)) {
		if (!config->show_forced_updates) {
			warning(_(warn_show_forced_updates));
		} else if (forced_updates_ms > FORCED_UPDATES_DELAY_WARNING_IN_MS) {
			warning(_(warn_time_show_forced_updates),
				forced_updates_ms / 1000.0);
		}
	}

 abort:
	strbuf_release(&note);
	return rc;
}

/*
 * We would want to bypass the object transfer altogether if
 * everything we are going to fetch already exists and is connected
 * locally.
 */
static int check_exist_and_connected(struct ref *ref_map)
{
	struct ref *rm = ref_map;
	struct check_connected_options opt = CHECK_CONNECTED_INIT;
	struct ref *r;

	/*
	 * If we are deepening a shallow clone we already have these
	 * objects reachable.  Running rev-list here will return with
	 * a good (0) exit status and we'll bypass the fetch that we
	 * really need to perform.  Claiming failure now will ensure
	 * we perform the network exchange to deepen our history.
	 */
	if (deepen)
		return -1;

	/*
	 * Similarly, if we need to refetch, we always want to perform a full
	 * fetch ignoring existing objects.
	 */
	if (refetch)
		return -1;


	/*
	 * check_connected() allows objects to merely be promised, but
	 * we need all direct targets to exist.
	 */
	for (r = rm; r; r = r->next) {
		if (!odb_has_object(the_repository->objects, &r->old_oid,
				    ODB_HAS_OBJECT_RECHECK_PACKED))
			return -1;
	}

	opt.quiet = 1;
	opt.exclude_hidden_refs_section = "fetch";
	return check_connected(iterate_ref_map, &rm, &opt);
}

static int fetch_and_consume_refs(struct display_state *display_state,
				  struct transport *transport,
				  struct ref_transaction *transaction,
				  struct ref *ref_map,
				  struct fetch_head *fetch_head,
				  const struct fetch_config *config,
				  struct ref_update_display_info_array *display_array)
{
	int connectivity_checked = 1;
	int ret;

	/*
	 * We don't need to perform a fetch in case we can already satisfy all
	 * refs.
	 */
	ret = check_exist_and_connected(ref_map);
	if (ret) {
		trace2_region_enter("fetch", "fetch_refs", the_repository);
		ret = transport_fetch_refs(transport, ref_map);
		trace2_region_leave("fetch", "fetch_refs", the_repository);
		if (ret)
			goto out;
		connectivity_checked = transport->smart_options ?
			transport->smart_options->connectivity_checked : 0;
	}

	trace2_region_enter("fetch", "consume_refs", the_repository);
	ret = store_updated_refs(display_state, connectivity_checked,
				 transaction, ref_map, fetch_head, config,
				 display_array);
	trace2_region_leave("fetch", "consume_refs", the_repository);

out:
	transport_unlock_pack(transport, 0);
	return ret;
}

static int prune_refs(struct display_state *display_state,
		      struct refspec *rs,
		      struct ref_transaction *transaction,
		      struct ref *ref_map)
{
	int result = 0;
	struct ref *ref, *stale_refs = get_stale_heads(rs, ref_map);
	struct strbuf err = STRBUF_INIT;
	struct string_list refnames = STRING_LIST_INIT_NODUP;

	for (ref = stale_refs; ref; ref = ref->next)
		string_list_append(&refnames, ref->name);

	if (!dry_run) {
		if (transaction) {
			for (ref = stale_refs; ref; ref = ref->next) {
				result = ref_transaction_delete(transaction, ref->name, NULL,
								NULL, 0, "fetch: prune", &err);
				if (result)
					goto cleanup;
			}
		} else {
			result = refs_delete_refs(get_main_ref_store(the_repository),
						  "fetch: prune", &refnames,
						  0);
		}
	}

	if (verbosity >= 0) {
		int summary_width = transport_summary_width(stale_refs);

		for (ref = stale_refs; ref; ref = ref->next) {
			display_ref_update(display_state, '-', _("[deleted]"), NULL,
					   _("(none)"), ref->name,
					   &ref->new_oid, &ref->old_oid,
					   summary_width);
		}
		string_list_sort(&refnames);
		refs_warn_dangling_symrefs(get_main_ref_store(the_repository),
					   stderr, "   ", dry_run, &refnames);
	}

cleanup:
	string_list_clear(&refnames, 0);
	strbuf_release(&err);
	free_refs(stale_refs);
	return result;
}

static void check_not_current_branch(struct ref *ref_map)
{
	const char *path;
	for (; ref_map; ref_map = ref_map->next)
		if (ref_map->peer_ref &&
		    starts_with(ref_map->peer_ref->name, "refs/heads/") &&
		    (path = branch_checked_out(ref_map->peer_ref->name)))
			die(_("refusing to fetch into branch '%s' "
			      "checked out at '%s'"),
			    ref_map->peer_ref->name, path);
}

static int truncate_fetch_head(void)
{
	const char *filename = git_path_fetch_head(the_repository);
	FILE *fp = fopen_for_writing(filename);

	if (!fp)
		return error_errno(_("cannot open '%s'"), filename);
	fclose(fp);
	return 0;
}

static void set_option(struct transport *transport, const char *name, const char *value)
{
	int r = transport_set_option(transport, name, value);
	if (r < 0)
		die(_("option \"%s\" value \"%s\" is not valid for %s"),
		    name, value, transport->url);
	if (r > 0)
		warning(_("option \"%s\" is ignored for %s"),
			name, transport->url);
}


static int add_oid(const struct reference *ref, void *cb_data)
{
	struct oid_array *oids = cb_data;

	oid_array_append(oids, ref->oid);
	return 0;
}

static void add_negotiation_tips(struct string_list *input_list,
				 struct oid_array **output_list,
				 const char *argname)
{
	struct oid_array *oids = xcalloc(1, sizeof(*oids));
	int i;

	for (i = 0; i < input_list->nr; i++) {
		const char *s = input_list->items[i].string;
		struct refs_for_each_ref_options opts = {
			.pattern = s,
		};
		int old_nr;
		if (!has_glob_specials(s)) {
			struct object_id oid;

			/* Ignore missing reference. */
			if (repo_get_oid(the_repository, s, &oid))
				continue;
			/* Fail on missing object pointed by ref. */
			if (!odb_has_object(the_repository->objects, &oid, 0))
				die(_("the object %s does not exist"), s);

			oid_array_append(oids, &oid);
			continue;
		}
		old_nr = oids->nr;
		refs_for_each_ref_ext(get_main_ref_store(the_repository),
				      add_oid, oids, &opts);
		if (old_nr == oids->nr)
			warning(_("ignoring %s=%s because it does not match any refs"),
				argname, s);
	}
	*output_list = oids;
}

static struct transport *prepare_transport(struct remote *remote, int deepen,
					   struct list_objects_filter_options *filter_options)
{
	struct transport *transport;

	transport = transport_get(remote, NULL);
	transport_set_verbosity(transport, verbosity, progress);
	transport->family = family;
	if (upload_pack)
		set_option(transport, TRANS_OPT_UPLOADPACK, upload_pack);
	if (keep)
		set_option(transport, TRANS_OPT_KEEP, "yes");
	if (depth)
		set_option(transport, TRANS_OPT_DEPTH, depth);
	if (deepen && deepen_since)
		set_option(transport, TRANS_OPT_DEEPEN_SINCE, deepen_since);
	if (deepen && deepen_not.nr)
		set_option(transport, TRANS_OPT_DEEPEN_NOT,
			   (const char *)&deepen_not);
	if (deepen_relative)
		set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, "yes");
	if (update_shallow)
		set_option(transport, TRANS_OPT_UPDATE_SHALLOW, "yes");
	if (refetch)
		set_option(transport, TRANS_OPT_REFETCH, "yes");
	if (filter_options->choice) {
		const char *spec =
			expand_list_objects_filter_spec(filter_options);
		set_option(transport, TRANS_OPT_LIST_OBJECTS_FILTER, spec);
		set_option(transport, TRANS_OPT_FROM_PROMISOR, "1");
	}
	if (negotiation_restrict.nr) {
		if (transport->smart_options)
			add_negotiation_tips(&negotiation_restrict,
					     &transport->smart_options->negotiation_restrict_tips,
					     "--negotiation-restrict");
		else
			warning(_("ignoring %s because the protocol does not support it"),
				"--negotiation-restrict");
	} else if (remote->negotiation_restrict.nr) {
		struct string_list_item *item;
		for_each_string_list_item(item, &remote->negotiation_restrict)
			string_list_append(&negotiation_restrict, item->string);
		if (transport->smart_options)
			add_negotiation_tips(&negotiation_restrict,
					     &transport->smart_options->negotiation_restrict_tips,
					     "--negotiation-restrict");
		else {
			struct strbuf config_name = STRBUF_INIT;
			strbuf_addf(&config_name, "remote.%s.negotiationRestrict", remote->name);
			warning(_("ignoring %s because the protocol does not support it"),
				config_name.buf);
			strbuf_release(&config_name);
		}
	}
	if (negotiation_include.nr) {
		if (transport->smart_options)
			add_negotiation_tips(&negotiation_include,
					     &transport->smart_options->negotiation_include_tips,
					     "--negotiation-include");
		else
			warning(_("ignoring %s because the protocol does not support it"),
				"--negotiation-include");
	} else if (remote->negotiation_include.nr) {
		if (transport->smart_options) {
			add_negotiation_tips(&remote->negotiation_include,
					     &transport->smart_options->negotiation_include_tips,
					     "--negotiation-include");
		} else {
			struct strbuf config_name = STRBUF_INIT;
			strbuf_addf(&config_name, "remote.%s.negotiationInclude", remote->name);
			warning(_("ignoring %s because the protocol does not support it"),
				config_name.buf);
			strbuf_release(&config_name);
		}
	}
	return transport;
}

static int backfill_tags(struct display_state *display_state,
			 struct transport *transport,
			 struct ref_transaction *transaction,
			 struct ref *ref_map,
			 struct fetch_head *fetch_head,
			 const struct fetch_config *config,
			 struct ref_update_display_info_array *display_array,
			 struct list_objects_filter_options *filter_options)
{
	int retcode, cannot_reuse;

	/*
	 * Once we have set TRANS_OPT_DEEPEN_SINCE, we can't unset it
	 * when remote helper is used (setting it to an empty string
	 * is not unsetting). We could extend the remote helper
	 * protocol for that, but for now, just force a new connection
	 * without deepen-since. Similar story for deepen-not.
	 */
	cannot_reuse = transport->cannot_reuse ||
		deepen_since || deepen_not.nr;
	if (cannot_reuse) {
		gsecondary = prepare_transport(transport->remote, 0, filter_options);
		transport = gsecondary;
	}

	transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, NULL);
	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
	retcode = fetch_and_consume_refs(display_state, transport, transaction, ref_map,
					 fetch_head, config, display_array);

	if (gsecondary) {
		transport_disconnect(gsecondary);
		gsecondary = NULL;
	}

	return retcode;
}

static const char *strip_refshead(const char *name){
	skip_prefix(name, "refs/heads/", &name);
	return name;
}

static void set_head_advice_msg(const char *remote, const char *head_name)
{
	const char message_advice_set_head[] =
	N_("Run 'git remote set-head %s %s' to follow the change, or modify\n"
	   "either of the 'remote.%s.followRemoteHEAD' or 'fetch.followRemoteHEAD'\n"
	   "configuration variables to handle the situation differently.\n\n"

	   "Using this specific setting\n\n"
	   "    git config set remote.%s.followRemoteHEAD warn-if-not-%s\n\n"
	   "will suppress the warning until the remote changes HEAD to something else.");

	advise_if_enabled(ADVICE_FETCH_SET_HEAD_WARN, _(message_advice_set_head),
			remote, head_name, remote, remote, head_name);
}

static void warn_set_head(const char *remote, const char *head_name,
			struct strbuf *buf_prev, int updateres) {
	struct strbuf buf_prefix = STRBUF_INIT;
	const char *prev_head = NULL;

	strbuf_addf(&buf_prefix, "refs/remotes/%s/", remote);
	skip_prefix(buf_prev->buf, buf_prefix.buf, &prev_head);

	if (prev_head && strcmp(prev_head, head_name)) {
		printf("'HEAD' at '%s' is '%s', but we have '%s' locally.\n",
			remote, head_name, prev_head);
		set_head_advice_msg(remote, head_name);
	}
	else if (updateres && buf_prev->len) {
		printf("'HEAD' at '%s' is '%s', "
			"but we have a detached HEAD pointing to '%s' locally.\n",
			remote, head_name, buf_prev->buf);
		set_head_advice_msg(remote, head_name);
	}
	strbuf_release(&buf_prefix);
}

static int set_head(const struct ref *remote_refs, struct remote *remote,
			int follow_remote_head)
{
	int result = 0, create_only, baremirror, was_detached;
	struct strbuf b_head = STRBUF_INIT, b_remote_head = STRBUF_INIT,
		      b_local_head = STRBUF_INIT;
	const char *no_warn_branch = remote->no_warn_branch;
	char *head_name = NULL;
	struct ref *ref, *matches;
	struct ref *fetch_map = NULL, **fetch_map_tail = &fetch_map;
	struct refspec_item refspec = {
		.force = 0,
		.pattern = 1,
		.src = (char *) "refs/heads/*",
		.dst = (char *) "refs/heads/*",
	};
	struct string_list heads = STRING_LIST_INIT_DUP;
	struct ref_store *refs = get_main_ref_store(the_repository);

	get_fetch_map(remote_refs, &refspec, &fetch_map_tail, 0);
	matches = guess_remote_head(find_ref_by_name(remote_refs, "HEAD"),
				    fetch_map, REMOTE_GUESS_HEAD_ALL);
	for (ref = matches; ref; ref = ref->next) {
		string_list_append(&heads, strip_refshead(ref->name));
	}

	if (!heads.nr)
		result = 1;
	else if (heads.nr > 1)
		result = 1;
	else
		head_name = xstrdup(heads.items[0].string);

	if (!head_name)
		goto cleanup;
	baremirror = is_bare_repository(the_repository) && remote->mirror;
	create_only = follow_remote_head == FOLLOW_REMOTE_ALWAYS ? 0 : !baremirror;
	if (baremirror) {
		strbuf_addstr(&b_head, "HEAD");
		strbuf_addf(&b_remote_head, "refs/heads/%s", head_name);
	} else {
		strbuf_addf(&b_head, "refs/remotes/%s/HEAD", remote->name);
		strbuf_addf(&b_remote_head, "refs/remotes/%s/%s", remote->name, head_name);
	}
	/* make sure it's valid */
	if (!baremirror && !refs_ref_exists(refs, b_remote_head.buf)) {
		result = 1;
		goto cleanup;
	}
	was_detached = refs_update_symref_extended(refs, b_head.buf, b_remote_head.buf,
					"fetch", &b_local_head, create_only);
	if (was_detached == -1) {
		result = 1;
		goto cleanup;
	}
	if (verbosity >= 0 &&
		follow_remote_head == FOLLOW_REMOTE_WARN &&
		(!no_warn_branch || strcmp(no_warn_branch, head_name)))
		warn_set_head(remote->name, head_name, &b_local_head, was_detached);

cleanup:
	free(head_name);
	free_refs(fetch_map);
	free_refs(matches);
	string_list_clear(&heads, 0);
	strbuf_release(&b_head);
	strbuf_release(&b_local_head);
	strbuf_release(&b_remote_head);
	return result;
}

struct ref_rejection_data {
	int *retcode;
	bool conflict_msg_shown;
	bool case_sensitive_msg_shown;
	const char *remote_name;
	struct strmap *rejected_refs;
};

static void ref_transaction_rejection_handler(const char *refname,
					      const struct object_id *old_oid UNUSED,
					      const struct object_id *new_oid UNUSED,
					      const char *old_target UNUSED,
					      const char *new_target UNUSED,
					      enum ref_transaction_error err,
					      const char *details,
					      void *cb_data)
{
	struct ref_rejection_data *data = cb_data;

	if (err == REF_TRANSACTION_ERROR_CASE_CONFLICT && repo_ignore_case(the_repository) &&
	    !data->case_sensitive_msg_shown) {
		error(_("You're on a case-insensitive filesystem, and the remote you are\n"
			"trying to fetch from has references that only differ in casing. It\n"
			"is impossible to store such references with the 'files' backend. You\n"
			"can either accept this as-is, in which case you won't be able to\n"
			"store all remote references on disk. Or you can alternatively\n"
			"migrate your repository to use the 'reftable' backend with the\n"
			"following command:\n\n    git refs migrate --ref-format=reftable\n\n"
			"Please keep in mind that not all implementations of Git support this\n"
			"new format yet. So if you use tools other than Git to access this\n"
			"repository it may not be an option to migrate to reftables.\n"));
		data->case_sensitive_msg_shown = true;
	} else if (err == REF_TRANSACTION_ERROR_NAME_CONFLICT &&
		   !data->conflict_msg_shown) {
		error(_("some local refs could not be updated; try running\n"
			" 'git remote prune %s' to remove any old, conflicting "
			"branches"), data->remote_name);
		data->conflict_msg_shown = true;
	} else {
		if (details)
			error("%s", details);
		else
			error(_("fetching ref %s failed: %s"),
			      refname, ref_transaction_error_msg(err));
	}

	strmap_put(data->rejected_refs, refname, NULL);
	*data->retcode = 1;
}

/*
 * Commit the reference transaction. If it isn't an atomic transaction, handle
 * rejected updates as part of using batched updates.
 */
static int commit_ref_transaction(struct ref_transaction **transaction,
				  bool is_atomic, const char *remote_name,
				  struct strmap *rejected_refs,
				  struct strbuf *err)
{
	int retcode = ref_transaction_commit(*transaction, err);
	if (retcode)
		goto out;

	if (!is_atomic) {
		struct ref_rejection_data data = {
			.conflict_msg_shown = 0,
			.remote_name = remote_name,
			.retcode = &retcode,
			.rejected_refs = rejected_refs,
		};

		ref_transaction_for_each_rejected_update(*transaction,
							 ref_transaction_rejection_handler,
							 &data);
	}

out:
	ref_transaction_free(*transaction);
	*transaction = NULL;
	return retcode;
}

static int do_fetch(struct transport *transport,
		    struct refspec *rs,
		    const struct fetch_config *config,
		    struct list_objects_filter_options *filter_options)
{
	struct ref_transaction *transaction = NULL;
	struct ref *ref_map = NULL;
	struct display_state display_state = { 0 };
	int autotags = (transport->remote->fetch_tags == 1);
	int retcode = 0;
	const struct ref *remote_refs;
	struct transport_ls_refs_options transport_ls_refs_options =
		TRANSPORT_LS_REFS_OPTIONS_INIT;
	struct fetch_head fetch_head = { 0 };
	struct strbuf err = STRBUF_INIT;
	int do_set_head = 0;
	struct ref_update_display_info_array display_array = { 0 };
	struct strmap rejected_refs = STRMAP_INIT;
	int summary_width = 0;
	int follow_remote_head;

	if (tags == TAGS_DEFAULT) {
		if (transport->remote->fetch_tags == 2)
			tags = TAGS_SET;
		if (transport->remote->fetch_tags == -1)
			tags = TAGS_UNSET;
	}

	/* if not appending, truncate FETCH_HEAD */
	if (!append && write_fetch_head) {
		retcode = truncate_fetch_head();
		if (retcode)
			goto cleanup;
	}

	/*
	 * NEEDSWORK: By the time this function executes, we have already parsed
	 * all such followRemoteHEAD values from the external configuration,
	 * potentially emitting warning messages for bogus values.  Ideally, if
	 * this fetch ends up not needing to consult these values, then git would
	 * not ever output a value warning. (eg: when pulling from a URL directly -
	 * rather than a configured remote, or when a remote's followRemoteHEAD
	 * overrides the fallback fetch setting)
	 */
	if (transport->remote->follow_remote_head)
		follow_remote_head = transport->remote->follow_remote_head;
	else if (config->follow_remote_head)
		follow_remote_head = config->follow_remote_head;
	else
		follow_remote_head = BUILTIN_FOLLOW_REMOTE_HEAD_DFLT;

	if (rs->nr) {
		refspec_ref_prefixes(rs, &transport_ls_refs_options.ref_prefixes);
	} else {
		struct branch *branch = branch_get(NULL);

		if (transport->remote->fetch.nr) {
			refspec_ref_prefixes(&transport->remote->fetch,
					     &transport_ls_refs_options.ref_prefixes);
			if (follow_remote_head != FOLLOW_REMOTE_NEVER)
				do_set_head = 1;
		}
		if (branch && branch_has_merge_config(branch) &&
		    !strcmp(branch->remote_name, transport->remote->name)) {
			int i;
			for (i = 0; i < branch->merge_nr; i++) {
				strvec_push(&transport_ls_refs_options.ref_prefixes,
					    branch->merge[i]->src);
			}
		}

		/*
		 * If there are no refs specified to fetch, then we just
		 * fetch HEAD; mention that to narrow the advertisement.
		 */
		if (!transport_ls_refs_options.ref_prefixes.nr)
			strvec_push(&transport_ls_refs_options.ref_prefixes,
				    "HEAD");
	}

	if (tags == TAGS_SET || tags == TAGS_DEFAULT)
		strvec_push(&transport_ls_refs_options.ref_prefixes,
			    "refs/tags/");

	if (do_set_head)
		strvec_push(&transport_ls_refs_options.ref_prefixes,
			    "HEAD");

	/*
	 * Only initiate ref listing if we have at least one ref we want to
	 * know about.
	 */
	if (transport_ls_refs_options.ref_prefixes.nr) {
		trace2_region_enter("fetch", "remote_refs", the_repository);
		remote_refs = transport_get_remote_refs(transport,
							&transport_ls_refs_options);
		trace2_region_leave("fetch", "remote_refs", the_repository);
	} else
		remote_refs = NULL;

	transport_ls_refs_options_release(&transport_ls_refs_options);

	ref_map = get_ref_map(transport->remote, remote_refs, rs,
			      tags, &autotags);
	if (!update_head_ok)
		check_not_current_branch(ref_map);

	retcode = open_fetch_head(&fetch_head);
	if (retcode)
		goto cleanup;

	display_state_init(&display_state, ref_map, transport->url,
			   config->display_format);

	if (atomic_fetch) {
		transaction = ref_store_transaction_begin(get_main_ref_store(the_repository),
							  0, &err);
		if (!transaction) {
			retcode = -1;
			goto cleanup;
		}
	}

	if (tags == TAGS_DEFAULT && autotags)
		transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, "1");
	if (prune) {
		/*
		 * We only prune based on refspecs specified
		 * explicitly (via command line or configuration); we
		 * don't care whether --tags was specified.
		 */
		if (rs->nr) {
			retcode = prune_refs(&display_state, rs, transaction, ref_map);
		} else {
			retcode = prune_refs(&display_state, &transport->remote->fetch,
					     transaction, ref_map);
		}
		if (retcode != 0)
			retcode = 1;
	}

	/*
	 * If not atomic, we can still use batched updates, which would be much
	 * more performant. We don't initiate the transaction before pruning,
	 * since pruning must be an independent step, to avoid F/D conflicts.
	 *
	 * TODO: if reference transactions gain logical conflict resolution, we
	 * can delete and create refs (with F/D conflicts) in the same transaction
	 * and this can be moved above the 'prune_refs()' block.
	 */
	if (!transaction) {
		transaction = ref_store_transaction_begin(get_main_ref_store(the_repository),
							  REF_TRANSACTION_ALLOW_FAILURE, &err);
		if (!transaction) {
			retcode = -1;
			goto cleanup;
		}
	}

	if (fetch_and_consume_refs(&display_state, transport, transaction, ref_map,
				   &fetch_head, config, &display_array)) {
		retcode = 1;
		goto cleanup;
	}

	/*
	 * If neither --no-tags nor --tags was specified, do automated tag
	 * following.
	 */
	if (tags == TAGS_DEFAULT && autotags) {
		struct ref *tags_ref_map = NULL, **tail = &tags_ref_map;

		find_non_local_tags(remote_refs, transaction, &tags_ref_map, &tail);
		if (tags_ref_map) {
			/*
			 * If backfilling of tags fails then we want to tell
			 * the user so, but we have to continue regardless to
			 * populate upstream information of the references we
			 * have already fetched above. The exception though is
			 * when `--atomic` is passed: in that case we'll abort
			 * the transaction and don't commit anything.
			 */
			if (backfill_tags(&display_state, transport, transaction, tags_ref_map,
					  &fetch_head, config, &display_array, filter_options))
				retcode = 1;
		}

		free_refs(tags_ref_map);
	}

	if (retcode)
		goto cleanup;

	if (verbosity >= 0)
		summary_width = transport_summary_width(ref_map);

	retcode = commit_ref_transaction(&transaction, atomic_fetch,
					 transport->remote->name,
					 &rejected_refs, &err);
	/*
	 * With '--atomic', bail out if the transaction fails. Without '--atomic',
	 * continue to fetch head and perform other post-fetch operations.
	 */
	if (retcode && atomic_fetch)
		goto cleanup;

	commit_fetch_head(&fetch_head);

	if (set_upstream) {
		struct branch *branch = branch_get("HEAD");
		struct ref *rm;
		struct ref *source_ref = NULL;

		/*
		 * We're setting the upstream configuration for the
		 * current branch. The relevant upstream is the
		 * fetched branch that is meant to be merged with the
		 * current one, i.e. the one fetched to FETCH_HEAD.
		 *
		 * When there are several such branches, consider the
		 * request ambiguous and err on the safe side by doing
		 * nothing and just emit a warning.
		 */
		for (rm = ref_map; rm; rm = rm->next) {
			if (!rm->peer_ref) {
				if (source_ref) {
					warning(_("multiple branches detected, incompatible with --set-upstream"));
					goto cleanup;
				} else {
					source_ref = rm;
				}
			}
		}
		if (source_ref) {
			if (!branch) {
				const char *shortname = source_ref->name;
				skip_prefix(shortname, "refs/heads/", &shortname);

				warning(_("could not set upstream of HEAD to '%s' from '%s' when "
					  "it does not point to any branch."),
					shortname, transport->remote->name);
				goto cleanup;
			}

			if (!strcmp(source_ref->name, "HEAD") ||
			    starts_with(source_ref->name, "refs/heads/"))
				install_branch_config(0,
						      branch->name,
						      transport->remote->name,
						      source_ref->name);
			else if (starts_with(source_ref->name, "refs/remotes/"))
				warning(_("not setting upstream for a remote remote-tracking branch"));
			else if (starts_with(source_ref->name, "refs/tags/"))
				warning(_("not setting upstream for a remote tag"));
			else
				warning(_("unknown branch type"));
		} else {
			warning(_("no source branch found;\n"
				  "you need to specify exactly one branch with the --set-upstream option"));
		}
	}
	if (do_set_head) {
		/*
		 * Way too many cases where this can go wrong so let's just
		 * ignore errors and fail silently for now.
		 */
		set_head(remote_refs, transport->remote, follow_remote_head);
	}

cleanup:
	/*
	 * When using batched updates, we want to commit the non-rejected
	 * updates and also handle the rejections.
	 */
	if (retcode && !atomic_fetch && transaction)
		commit_ref_transaction(&transaction, false,
				       transport->remote->name,
				       &rejected_refs, &err);

	for (size_t i = 0; i < display_array.nr; i++) {
		struct ref_update_display_info *info = &display_array.info[i];

		if (!info->failed && strmap_contains(&rejected_refs, info->ref))
			ref_update_display_info_set_failed(info);
		ref_update_display_info_display(info, &display_state, summary_width);
		ref_update_display_info_free(info);
	}

	if (retcode) {
		if (err.len) {
			error("%s", err.buf);
			strbuf_reset(&err);
		}
		if (transaction && ref_transaction_abort(transaction, &err) &&
		    err.len)
			error("%s", err.buf);
		transaction = NULL;
	}

	if (transaction)
		ref_transaction_free(transaction);

	free(display_array.info);
	strmap_clear(&rejected_refs, 0);
	display_state_release(&display_state);
	close_fetch_head(&fetch_head);
	strbuf_release(&err);
	free_refs(ref_map);
	return retcode;
}

static int get_one_remote_for_fetch(struct remote *remote, void *priv)
{
	struct string_list *list = priv;
	if (!remote->skip_default_update)
		string_list_append(list, remote->name);
	return 0;
}

static void add_options_to_argv(struct strvec *argv,
				const struct fetch_config *config)
{
	if (dry_run)
		strvec_push(argv, "--dry-run");
	if (prune != -1)
		strvec_push(argv, prune ? "--prune" : "--no-prune");
	if (prune_tags != -1)
		strvec_push(argv, prune_tags ? "--prune-tags" : "--no-prune-tags");
	if (update_head_ok)
		strvec_push(argv, "--update-head-ok");
	if (force)
		strvec_push(argv, "--force");
	if (keep)
		strvec_push(argv, "--keep");
	if (config->recurse_submodules == RECURSE_SUBMODULES_ON)
		strvec_push(argv, "--recurse-submodules");
	else if (config->recurse_submodules == RECURSE_SUBMODULES_OFF)
		strvec_push(argv, "--no-recurse-submodules");
	else if (config->recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND)
		strvec_push(argv, "--recurse-submodules=on-demand");
	if (tags == TAGS_SET)
		strvec_push(argv, "--tags");
	else if (tags == TAGS_UNSET)
		strvec_push(argv, "--no-tags");
	if (verbosity >= 2)
		strvec_push(argv, "-v");
	if (verbosity >= 1)
		strvec_push(argv, "-v");
	else if (verbosity < 0)
		strvec_push(argv, "-q");
	if (family == TRANSPORT_FAMILY_IPV4)
		strvec_push(argv, "--ipv4");
	else if (family == TRANSPORT_FAMILY_IPV6)
		strvec_push(argv, "--ipv6");
	if (!write_fetch_head)
		strvec_push(argv, "--no-write-fetch-head");
	if (config->display_format == DISPLAY_FORMAT_PORCELAIN)
		strvec_pushf(argv, "--porcelain");
}

/* Fetch multiple remotes in parallel */

struct parallel_fetch_state {
	const char **argv;
	struct string_list *remotes;
	int next, result;
	const struct fetch_config *config;
};

static int fetch_next_remote(struct child_process *cp,
			     struct strbuf *out UNUSED,
			     void *cb, void **task_cb)
{
	struct parallel_fetch_state *state = cb;
	char *remote;

	if (state->next < 0 || state->next >= state->remotes->nr)
		return 0;

	remote = state->remotes->items[state->next++].string;
	*task_cb = remote;

	strvec_pushv(&cp->args, state->argv);
	strvec_push(&cp->args, remote);
	cp->git_cmd = 1;

	if (verbosity >= 0 && state->config->display_format != DISPLAY_FORMAT_PORCELAIN)
		printf(_("Fetching %s\n"), remote);

	return 1;
}

static int fetch_failed_to_start(struct strbuf *out UNUSED,
				 void *cb, void *task_cb)
{
	struct parallel_fetch_state *state = cb;
	const char *remote = task_cb;

	state->result = error(_("could not fetch %s"), remote);

	return 0;
}

static int fetch_finished(int result, struct strbuf *out,
			  void *cb, void *task_cb)
{
	struct parallel_fetch_state *state = cb;
	const char *remote = task_cb;

	if (result) {
		strbuf_addf(out, _("could not fetch '%s' (exit code: %d)\n"),
			    remote, result);
		state->result = -1;
	}

	return 0;
}

static int fetch_multiple(struct string_list *list, int max_children,
			  const struct fetch_config *config)
{
	int i, result = 0;
	struct strvec argv = STRVEC_INIT;

	if (!append && write_fetch_head) {
		int errcode = truncate_fetch_head();
		if (errcode)
			return errcode;
	}

	/*
	 * Cancel out the fetch.bundleURI config when running subprocesses,
	 * to avoid fetching from the same bundle list multiple times.
	 */
	strvec_pushl(&argv, "-c", "fetch.bundleURI=",
		     "fetch", "--append", "--no-auto-gc",
		     "--no-write-commit-graph", NULL);
	for (i = 0; i < server_options.nr; i++)
		strvec_pushf(&argv, "--server-option=%s", server_options.items[i].string);
	add_options_to_argv(&argv, config);

	if (max_children != 1 && list->nr != 1) {
		struct parallel_fetch_state state = { argv.v, list, 0, 0, config };
		const struct run_process_parallel_opts opts = {
			.tr2_category = "fetch",
			.tr2_label = "parallel/fetch",

			.processes = max_children,

			.get_next_task = &fetch_next_remote,
			.start_failure = &fetch_failed_to_start,
			.task_finished = &fetch_finished,
			.data = &state,
		};

		strvec_push(&argv, "--end-of-options");

		run_processes_parallel(&opts);
		result = state.result;
	} else
		for (i = 0; i < list->nr; i++) {
			const char *name = list->items[i].string;
			struct child_process cmd = CHILD_PROCESS_INIT;

			strvec_pushv(&cmd.args, argv.v);
			strvec_push(&cmd.args, name);
			if (verbosity >= 0 && config->display_format != DISPLAY_FORMAT_PORCELAIN)
				printf(_("Fetching %s\n"), name);
			cmd.git_cmd = 1;
			if (run_command(&cmd)) {
				error(_("could not fetch %s"), name);
				result = 1;
			}
		}

	strvec_clear(&argv);
	return !!result;
}

/*
 * Fetching from the promisor remote should use the given filter-spec
 * or inherit the default filter-spec from the config.
 */
static inline void fetch_one_setup_partial(struct remote *remote,
					   struct list_objects_filter_options *filter_options)
{
	/*
	 * Explicit --no-filter argument overrides everything, regardless
	 * of any prior partial clones and fetches.
	 */
	if (filter_options->no_filter)
		return;

	/*
	 * If no prior partial clone/fetch and the current fetch DID NOT
	 * request a partial-fetch, do a normal fetch.
	 */
	if (!repo_has_promisor_remote(the_repository) && !filter_options->choice)
		return;

	/*
	 * If this is a partial-fetch request, we enable partial on
	 * this repo if not already enabled and remember the given
	 * filter-spec as the default for subsequent fetches to this
	 * remote if there is currently no default filter-spec.
	 */
	if (filter_options->choice) {
		partial_clone_register(remote->name, filter_options);
		return;
	}

	/*
	 * Do a partial-fetch from the promisor remote using either the
	 * explicitly given filter-spec or inherit the filter-spec from
	 * the config.
	 */
	if (!filter_options->choice)
		partial_clone_get_default_filter_spec(filter_options, remote->name);
	return;
}

static int fetch_one(struct remote *remote, int argc, const char **argv,
		     int prune_tags_ok, int use_stdin_refspecs,
		     const struct fetch_config *config,
		     struct list_objects_filter_options *filter_options)
{
	struct refspec rs = REFSPEC_INIT_FETCH(the_hash_algo);
	int i;
	int exit_code;
	int maybe_prune_tags;
	int remote_via_config = remote_is_configured(remote, 0);

	if (!remote)
		die(_("no remote repository specified; please specify either a URL or a\n"
		      "remote name from which new revisions should be fetched"));

	gtransport = prepare_transport(remote, 1, filter_options);

	if (prune < 0) {
		/* no command line request */
		if (0 <= remote->prune)
			prune = remote->prune;
		else if (0 <= config->prune)
			prune = config->prune;
		else
			prune = PRUNE_BY_DEFAULT;
	}

	if (prune_tags < 0) {
		/* no command line request */
		if (0 <= remote->prune_tags)
			prune_tags = remote->prune_tags;
		else if (0 <= config->prune_tags)
			prune_tags = config->prune_tags;
		else
			prune_tags = PRUNE_TAGS_BY_DEFAULT;
	}

	maybe_prune_tags = prune_tags_ok && prune_tags;
	if (maybe_prune_tags && remote_via_config)
		refspec_append(&remote->fetch, TAG_REFSPEC);

	if (maybe_prune_tags && (argc || !remote_via_config))
		refspec_append(&rs, TAG_REFSPEC);

	for (i = 0; i < argc; i++) {
		if (!strcmp(argv[i], "tag")) {
			i++;
			if (i >= argc)
				die(_("you need to specify a tag name"));

			refspec_appendf(&rs, "refs/tags/%s:refs/tags/%s",
					argv[i], argv[i]);
		} else {
			refspec_append(&rs, argv[i]);
		}
	}

	if (use_stdin_refspecs) {
		struct strbuf line = STRBUF_INIT;
		while (strbuf_getline_lf(&line, stdin) != EOF)
			refspec_append(&rs, line.buf);
		strbuf_release(&line);
	}

	if (server_options.nr)
		gtransport->server_options = &server_options;

	sigchain_push_common(unlock_pack_on_signal);
	atexit(unlock_pack_atexit);
	sigchain_push(SIGPIPE, SIG_IGN);
	exit_code = do_fetch(gtransport, &rs, config, filter_options);
	sigchain_pop(SIGPIPE);
	refspec_clear(&rs);
	transport_disconnect(gtransport);
	gtransport = NULL;
	return exit_code;
}

int cmd_fetch(int argc,
	      const char **argv,
	      const char *prefix,
	      struct repository *repo UNUSED)
{
	struct fetch_config config = {
		.display_format = DISPLAY_FORMAT_FULL,
		.follow_remote_head = FOLLOW_REMOTE_UNCONFIGURED,
		.prune = -1,
		.prune_tags = -1,
		.show_forced_updates = 1,
		.recurse_submodules = RECURSE_SUBMODULES_DEFAULT,
		.parallel = 1,
		.submodule_fetch_jobs = -1,
	};
	const char *submodule_prefix = "";
	const char *bundle_uri;
	struct string_list list = STRING_LIST_INIT_DUP;
	struct list_objects_filter_options filter_options = LIST_OBJECTS_FILTER_INIT;
	struct remote *remote = NULL;
	int all = -1, multiple = 0;
	int result = 0;
	int prune_tags_ok = 1;
	int enable_auto_gc = 1;
	int unshallow = 0;
	int max_jobs = -1;
	int recurse_submodules_cli = RECURSE_SUBMODULES_DEFAULT;
	int recurse_submodules_default = RECURSE_SUBMODULES_ON_DEMAND;
	int fetch_write_commit_graph = -1;
	int stdin_refspecs = 0;
	int negotiate_only = 0;
	int porcelain = 0;
	int i;

	struct option builtin_fetch_options[] = {
		OPT__VERBOSITY(&verbosity),
		OPT_BOOL(0, "all", &all,
			 N_("fetch from all remotes")),
		OPT_BOOL(0, "set-upstream", &set_upstream,
			 N_("set upstream for git pull/fetch")),
		OPT_BOOL('a', "append", &append,
			 N_("append to .git/FETCH_HEAD instead of overwriting")),
		OPT_BOOL(0, "atomic", &atomic_fetch,
			 N_("use atomic transaction to update references")),
		OPT_STRING(0, "upload-pack", &upload_pack, N_("path"),
			   N_("path to upload pack on remote end")),
		OPT__FORCE(&force, N_("force overwrite of local reference"), 0),
		OPT_BOOL('m', "multiple", &multiple,
			 N_("fetch from multiple remotes")),
		OPT_SET_INT('t', "tags", &tags,
			    N_("fetch all tags and associated objects"), TAGS_SET),
		OPT_SET_INT('n', NULL, &tags,
			    N_("do not fetch all tags (--no-tags)"), TAGS_UNSET),
		OPT_INTEGER('j', "jobs", &max_jobs,
			    N_("number of submodules fetched in parallel")),
		OPT_BOOL(0, "prefetch", &prefetch,
			 N_("modify the refspec to place all refs within refs/prefetch/")),
		OPT_BOOL('p', "prune", &prune,
			 N_("prune remote-tracking branches no longer on remote")),
		OPT_BOOL('P', "prune-tags", &prune_tags,
			 N_("prune local tags no longer on remote and clobber changed tags")),
		OPT_CALLBACK_F(0, "recurse-submodules", &recurse_submodules_cli, N_("on-demand"),
			    N_("control recursive fetching of submodules"),
			    PARSE_OPT_OPTARG, option_fetch_parse_recurse_submodules),
		OPT_BOOL(0, "dry-run", &dry_run,
			 N_("dry run")),
		OPT_BOOL(0, "porcelain", &porcelain, N_("machine-readable output")),
		OPT_BOOL(0, "write-fetch-head", &write_fetch_head,
			 N_("write fetched references to the FETCH_HEAD file")),
		OPT_BOOL('k', "keep", &keep, N_("keep downloaded pack")),
		OPT_BOOL('u', "update-head-ok", &update_head_ok,
			    N_("allow updating of HEAD ref")),
		OPT_BOOL(0, "progress", &progress, N_("force progress reporting")),
		OPT_STRING(0, "depth", &depth, N_("depth"),
			   N_("deepen history of shallow clone")),
		OPT_STRING(0, "shallow-since", &deepen_since, N_("time"),
			   N_("deepen history of shallow repository based on time")),
		OPT_STRING_LIST(0, "shallow-exclude", &deepen_not, N_("ref"),
				N_("deepen history of shallow clone, excluding ref")),
		OPT_INTEGER(0, "deepen", &deepen_relative,
			    N_("deepen history of shallow clone")),
		OPT_SET_INT_F(0, "unshallow", &unshallow,
			      N_("convert to a complete repository"),
			      1, PARSE_OPT_NONEG),
		OPT_SET_INT_F(0, "refetch", &refetch,
			      N_("re-fetch without negotiating common commits"),
			      1, PARSE_OPT_NONEG),
		{
			.type = OPTION_STRING,
			.long_name = "submodule-prefix",
			.value = &submodule_prefix,
			.argh = N_("dir"),
			.help = N_("prepend this to submodule path output"),
			.flags = PARSE_OPT_HIDDEN,
		},
		OPT_CALLBACK_F(0, "recurse-submodules-default",
			   &recurse_submodules_default, N_("on-demand"),
			   N_("default for recursive fetching of submodules "
			      "(lower priority than config files)"),
			   PARSE_OPT_HIDDEN, option_fetch_parse_recurse_submodules),
		OPT_BOOL(0, "update-shallow", &update_shallow,
			 N_("accept refs that update .git/shallow")),
		OPT_CALLBACK_F(0, "refmap", &refmap, N_("refmap"),
			       N_("specify fetch refmap"), PARSE_OPT_NONEG, parse_refmap_arg),
		OPT_STRING_LIST('o', "server-option", &server_options, N_("server-specific"), N_("option to transmit")),
		OPT_IPVERSION(&family),
		OPT_STRING_LIST(0, "negotiation-restrict", &negotiation_restrict, N_("revision"),
				N_("report that we have only objects reachable from this object")),
		OPT_ALIAS(0, "negotiation-tip", "negotiation-restrict"),
		OPT_STRING_LIST(0, "negotiation-include", &negotiation_include, N_("revision"),
				N_("ensure this ref is always sent as a negotiation have")),
		OPT_BOOL(0, "negotiate-only", &negotiate_only,
			 N_("do not fetch a packfile; instead, print ancestors of negotiation tips")),
		OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
		OPT_BOOL(0, "auto-maintenance", &enable_auto_gc,
			 N_("run 'maintenance --auto' after fetching")),
		OPT_BOOL(0, "auto-gc", &enable_auto_gc,
			 N_("run 'maintenance --auto' after fetching")),
		OPT_BOOL(0, "show-forced-updates", &config.show_forced_updates,
			 N_("check for forced-updates on all updated branches")),
		OPT_BOOL(0, "write-commit-graph", &fetch_write_commit_graph,
			 N_("write the commit-graph after fetching")),
		OPT_BOOL(0, "stdin", &stdin_refspecs,
			 N_("accept refspecs from stdin")),
		OPT_END()
	};

	filter_options.allow_auto_filter = 1;

	refspec_init_fetch(&refmap, the_hash_algo);

	packet_trace_identity("fetch");

	/* Record the command line for the reflog */
	strbuf_addstr(&default_rla, "fetch");
	for (i = 1; i < argc; i++) {
		/* This handles non-URLs gracefully */
		char *anon = transport_anonymize_url(argv[i]);

		strbuf_addf(&default_rla, " %s", anon);
		free(anon);
	}

	repo_config(the_repository, git_fetch_config, &config);
	if (the_repository->gitdir) {
		prepare_repo_settings(the_repository);
		the_repository->settings.command_requires_full_index = 0;
	}

	argc = parse_options(argc, argv, prefix,
			     builtin_fetch_options, builtin_fetch_usage, 0);

	if (recurse_submodules_cli != RECURSE_SUBMODULES_DEFAULT)
		config.recurse_submodules = recurse_submodules_cli;

	if (negotiate_only) {
		switch (recurse_submodules_cli) {
		case RECURSE_SUBMODULES_OFF:
		case RECURSE_SUBMODULES_DEFAULT:
			/*
			 * --negotiate-only should never recurse into
			 * submodules. Skip it by setting recurse_submodules to
			 * RECURSE_SUBMODULES_OFF.
			 */
			config.recurse_submodules = RECURSE_SUBMODULES_OFF;
			break;

		default:
			die(_("options '%s' and '%s' cannot be used together"),
			    "--negotiate-only", "--recurse-submodules");
		}
	}

	if (config.recurse_submodules != RECURSE_SUBMODULES_OFF) {
		int *sfjc = config.submodule_fetch_jobs == -1
			    ? &config.submodule_fetch_jobs : NULL;
		int *rs = config.recurse_submodules == RECURSE_SUBMODULES_DEFAULT
			  ? &config.recurse_submodules : NULL;

		fetch_config_from_gitmodules(sfjc, rs);
	}


	if (porcelain) {
		switch (recurse_submodules_cli) {
		case RECURSE_SUBMODULES_OFF:
		case RECURSE_SUBMODULES_DEFAULT:
			/*
			 * Reference updates in submodules would be ambiguous
			 * in porcelain mode, so we reject this combination.
			 */
			config.recurse_submodules = RECURSE_SUBMODULES_OFF;
			break;

		default:
			die(_("options '%s' and '%s' cannot be used together"),
			    "--porcelain", "--recurse-submodules");
		}

		config.display_format = DISPLAY_FORMAT_PORCELAIN;
	}

	if (deepen_relative) {
		if (deepen_relative < 0)
			die(_("negative depth in --deepen is not supported"));
		if (depth)
			die(_("options '%s' and '%s' cannot be used together"), "--deepen", "--depth");
		depth = xstrfmt("%d", deepen_relative);
	}
	if (unshallow) {
		if (depth)
			die(_("options '%s' and '%s' cannot be used together"), "--depth", "--unshallow");
		else if (!is_repository_shallow(the_repository))
			die(_("--unshallow on a complete repository does not make sense"));
		else
			depth = xstrfmt("%d", INFINITE_DEPTH);
	}

	/* no need to be strict, transport_set_option() will validate it again */
	if (depth && atoi(depth) < 1)
		die(_("depth %s is not a positive number"), depth);
	if (depth || deepen_since || deepen_not.nr)
		deepen = 1;

	/* FETCH_HEAD never gets updated in --dry-run mode */
	if (dry_run)
		write_fetch_head = 0;

	if (!max_jobs)
		max_jobs = online_cpus();

	if (!repo_config_get_string_tmp(the_repository, "fetch.bundleuri", &bundle_uri) &&
	    fetch_bundle_uri(the_repository, bundle_uri, NULL))
		warning(_("failed to fetch bundles from '%s'"), bundle_uri);

	if (all < 0) {
		/*
		 * no --[no-]all given;
		 * only use config option if no remote was explicitly specified
		 */
		all = (!argc) ? config.all : 0;
	}

	if (all) {
		if (argc == 1)
			die(_("fetch --all does not take a repository argument"));
		else if (argc > 1)
			die(_("fetch --all does not make sense with refspecs"));

		(void) for_each_remote(get_one_remote_for_fetch, &list);

		/* do not do fetch_multiple() of one */
		if (list.nr == 1)
			remote = remote_get(list.items[0].string);
	} else if (argc == 0) {
		/* No arguments -- use default remote */
		remote = remote_get(NULL);
	} else if (multiple) {
		/* All arguments are assumed to be remotes or groups */
		for (i = 0; i < argc; i++)
			if (!add_remote_or_group(argv[i], &list))
				die(_("no such remote or remote group: %s"),
				    argv[i]);
	} else {
		/* Single remote or group */
		(void) add_remote_or_group(argv[0], &list);
		if (list.nr > 1) {
			/* More than one remote */
			if (argc > 1)
				die(_("fetching a group and specifying refspecs does not make sense"));
		} else {
			/* Zero or one remotes */
			remote = remote_get(argv[0]);
			prune_tags_ok = (argc == 1);
			argc--;
			argv++;
		}
	}
	string_list_remove_duplicates(&list, 0);

	if (negotiate_only) {
		struct oidset acked_commits = OIDSET_INIT;
		struct oidset_iter iter;
		const struct object_id *oid;

		trace2_region_enter("fetch", "negotiate-only", the_repository);
		if (!remote)
			die(_("must supply remote when using --negotiate-only"));
		gtransport = prepare_transport(remote, 1, &filter_options);

		if (!gtransport->smart_options) {
			warning(_("protocol does not support --negotiate-only, exiting"));
			result = 1;
			trace2_region_leave("fetch", "negotiate-only", the_repository);
			goto cleanup;
		}
		if (!gtransport->smart_options->negotiation_restrict_tips)
			die(_("%s needs one or more %s"), "--negotiate-only",
			    "--negotiation-restrict=*");

		gtransport->smart_options->acked_commits = &acked_commits;

		if (server_options.nr)
			gtransport->server_options = &server_options;
		result = transport_fetch_refs(gtransport, NULL);
		gtransport->smart_options->acked_commits = NULL;

		oidset_iter_init(&acked_commits, &iter);
		while ((oid = oidset_iter_next(&iter)))
			printf("%s\n", oid_to_hex(oid));
		oidset_clear(&acked_commits);
		trace2_region_leave("fetch", "negotiate-only", the_repository);
	} else if (remote) {
		if (filter_options.choice || repo_has_promisor_remote(the_repository)) {
			trace2_region_enter("fetch", "setup-partial", the_repository);
			fetch_one_setup_partial(remote, &filter_options);
			trace2_region_leave("fetch", "setup-partial", the_repository);
		}
		trace2_region_enter("fetch", "fetch-one", the_repository);
		result = fetch_one(remote, argc, argv, prune_tags_ok, stdin_refspecs,
				   &config, &filter_options);
		trace2_region_leave("fetch", "fetch-one", the_repository);
	} else {
		int max_children = max_jobs;

		if (filter_options.choice)
			die(_("--filter can only be used with the remote "
			      "configured in extensions.partialclone"));

		if (atomic_fetch)
			die(_("--atomic can only be used when fetching "
			      "from one remote"));

		if (stdin_refspecs)
			die(_("--stdin can only be used when fetching "
			      "from one remote"));

		if (max_children < 0)
			max_children = config.parallel;

		/* TODO should this also die if we have a previous partial-clone? */
		trace2_region_enter("fetch", "fetch-multiple", the_repository);
		result = fetch_multiple(&list, max_children, &config);
		trace2_region_leave("fetch", "fetch-multiple", the_repository);
	}

	/*
	 * This is only needed after fetch_one(), which does not fetch
	 * submodules by itself.
	 *
	 * When we fetch from multiple remotes, fetch_multiple() has
	 * already updated submodules to grab commits necessary for
	 * the fetched history from each remote, so there is no need
	 * to fetch submodules from here.
	 */
	if (!result && remote && (config.recurse_submodules != RECURSE_SUBMODULES_OFF)) {
		struct strvec options = STRVEC_INIT;
		int max_children = max_jobs;

		if (max_children < 0)
			max_children = config.submodule_fetch_jobs;
		if (max_children < 0)
			max_children = config.parallel;

		add_options_to_argv(&options, &config);
		trace2_region_enter_printf("fetch", "recurse-submodule", the_repository, "%s", submodule_prefix);
		result = fetch_submodules(the_repository,
					  &options,
					  submodule_prefix,
					  config.recurse_submodules,
					  recurse_submodules_default,
					  verbosity < 0,
					  max_children);
		trace2_region_leave_printf("fetch", "recurse-submodule", the_repository, "%s", submodule_prefix);
		strvec_clear(&options);
	}

	/*
	 * Skip irrelevant tasks because we know objects were not
	 * fetched.
	 *
	 * NEEDSWORK: as a future optimization, we can return early
	 * whenever objects were not fetched e.g. if we already have all
	 * of them.
	 */
	if (negotiate_only)
		goto cleanup;

	prepare_repo_settings(the_repository);
	if (fetch_write_commit_graph > 0 ||
	    (fetch_write_commit_graph < 0 &&
	     the_repository->settings.fetch_write_commit_graph)) {
		int commit_graph_flags = COMMIT_GRAPH_WRITE_SPLIT;

		if (progress)
			commit_graph_flags |= COMMIT_GRAPH_WRITE_PROGRESS;

		trace2_region_enter("fetch", "write-commit-graph", the_repository);
		write_commit_graph_reachable(the_repository->objects->sources,
					     commit_graph_flags,
					     NULL);
		trace2_region_leave("fetch", "write-commit-graph", the_repository);
	}

	if (enable_auto_gc) {
		if (refetch) {
			/*
			 * Hint auto-maintenance strongly to encourage repacking,
			 * but respect config settings disabling it.
			 */
			int opt_val;
			if (repo_config_get_int(the_repository, "gc.autopacklimit", &opt_val))
				opt_val = -1;
			if (opt_val != 0)
				git_config_push_parameter("gc.autoPackLimit=1");

			if (repo_config_get_int(the_repository, "maintenance.incremental-repack.auto", &opt_val))
				opt_val = -1;
			if (opt_val != 0)
				git_config_push_parameter("maintenance.incremental-repack.auto=-1");
		}
		run_auto_maintenance(the_repository, verbosity < 0);
	}

 cleanup:
	string_list_clear(&list, 0);
	list_objects_filter_release(&filter_options);
	return result;
}