Merge branch 'ak/protect-any-current-branch'

"git fetch" without the "--update-head-ok" option ought to protect
a checked out branch from getting updated, to prevent the working
tree that checks it out to go out of sync.  The code was written
before the use of "git worktree" got widespread, and only checked
the branch that was checked out in the current worktree, which has
been updated.
(originally called ak/fetch-not-overwrite-any-current-branch)

* ak/protect-any-current-branch:
  branch: protect branches checked out in all worktrees
  receive-pack: protect current branch for bare repository worktree
  receive-pack: clean dead code from update_worktree()
  fetch: protect branches checked out in all worktrees
  worktree: simplify find_shared_symref() memory ownership model
  branch: lowercase error messages
  receive-pack: lowercase error messages
  fetch: lowercase error messages

11 files changed, 198 insertions, 131 deletions

diff --git a/branch.c b/branch.c
index 07a46430b3..2cfe496d24 100644
--- a/branch.c
+++ b/branch.c
@@ -64,7 +64,7 @@ int install_branch_config(int flag, const char *local, const char *origin, const
 	if (skip_prefix(remote, "refs/heads/", &shortname)
 	    && !strcmp(local, shortname)
 	    && !origin) {
-		warning(_("Not setting branch %s as its own upstream."),
+		warning(_("not setting branch %s as its own upstream"),
 			local);
 		return 0;
 	}
@@ -116,7 +116,7 @@ int install_branch_config(int flag, const char *local, const char *origin, const
 
 out_err:
 	strbuf_release(&key);
-	error(_("Unable to write upstream branch configuration"));
+	error(_("unable to write upstream branch configuration"));
 
 	advise(_(tracking_advice),
 	       origin ? origin : "",
@@ -153,7 +153,7 @@ static void setup_tracking(const char *new_ref, const char *orig_ref,
 		}
 
 	if (tracking.matches > 1)
-		die(_("Not tracking: ambiguous information for ref %s"),
+		die(_("not tracking: ambiguous information for ref %s"),
 		    orig_ref);
 
 	if (install_branch_config(config_flags, new_ref, tracking.remote,
@@ -186,7 +186,7 @@ int read_branch_desc(struct strbuf *buf, const char *branch_name)
 int validate_branchname(const char *name, struct strbuf *ref)
 {
 	if (strbuf_check_branch_ref(ref, name))
-		die(_("'%s' is not a valid branch name."), name);
+		die(_("'%s' is not a valid branch name"), name);
 
 	return ref_exists(ref->buf);
 }
@@ -199,18 +199,23 @@ int validate_branchname(const char *name, struct strbuf *ref)
  */
 int validate_new_branchname(const char *name, struct strbuf *ref, int force)
 {
-	const char *head;
+	struct worktree **worktrees;
+	const struct worktree *wt;
 
 	if (!validate_branchname(name, ref))
 		return 0;
 
 	if (!force)
-		die(_("A branch named '%s' already exists."),
+		die(_("a branch named '%s' already exists"),
 		    ref->buf + strlen("refs/heads/"));
 
-	head = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
-	if (!is_bare_repository() && head && !strcmp(head, ref->buf))
-		die(_("Cannot force update the current branch."));
+	worktrees = get_worktrees();
+	wt = find_shared_symref(worktrees, "HEAD", ref->buf);
+	if (wt && !wt->is_bare)
+		die(_("cannot force update the branch '%s'"
+		      "checked out at '%s'"),
+		    ref->buf + strlen("refs/heads/"), wt->path);
+	free_worktrees(worktrees);
 
 	return 1;
 }
@@ -230,7 +235,7 @@ static int validate_remote_tracking_branch(char *ref)
 }
 
 static const char upstream_not_branch[] =
-N_("Cannot setup tracking information; starting point '%s' is not a branch.");
+N_("cannot set up tracking information; starting point '%s' is not a branch");
 static const char upstream_missing[] =
 N_("the requested upstream branch '%s' does not exist");
 static const char upstream_advice[] =
@@ -278,7 +283,7 @@ void create_branch(struct repository *r,
 			}
 			die(_(upstream_missing), start_name);
 		}
-		die(_("Not a valid object name: '%s'."), start_name);
+		die(_("not a valid object name: '%s'"), start_name);
 	}
 
 	switch (dwim_ref(start_name, strlen(start_name), &oid, &real_ref, 0)) {
@@ -298,12 +303,12 @@ void create_branch(struct repository *r,
 		}
 		break;
 	default:
-		die(_("Ambiguous object name: '%s'."), start_name);
+		die(_("ambiguous object name: '%s'"), start_name);
 		break;
 	}
 
 	if ((commit = lookup_commit_reference(r, &oid)) == NULL)
-		die(_("Not a valid branch point: '%s'."), start_name);
+		die(_("not a valid branch point: '%s'"), start_name);
 	oidcpy(&oid, &commit->object.oid);
 
 	if (reflog)
@@ -357,14 +362,16 @@ void remove_branch_state(struct repository *r, int verbose)
 
 void die_if_checked_out(const char *branch, int ignore_current_worktree)
 {
+	struct worktree **worktrees = get_worktrees();
 	const struct worktree *wt;
 
-	wt = find_shared_symref("HEAD", branch);
-	if (!wt || (ignore_current_worktree && wt->is_current))
-		return;
-	skip_prefix(branch, "refs/heads/", &branch);
-	die(_("'%s' is already checked out at '%s'"),
-	    branch, wt->path);
+	wt = find_shared_symref(worktrees, "HEAD", branch);
+	if (wt && (!ignore_current_worktree || !wt->is_current)) {
+		skip_prefix(branch, "refs/heads/", &branch);
+		die(_("'%s' is already checked out at '%s'"), branch, wt->path);
+	}
+
+	free_worktrees(worktrees);
 }
 
 int replace_each_worktree_head_symref(const char *oldref, const char *newref,
diff --git a/builtin/branch.c b/builtin/branch.c
index 81b5c111cb..6c8b0fcc11 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -192,6 +192,7 @@ static void delete_branch_config(const char *branchname)
 static int delete_branches(int argc, const char **argv, int force, int kinds,
 			   int quiet)
 {
+	struct worktree **worktrees;
 	struct commit *head_rev = NULL;
 	struct object_id oid;
 	char *name = NULL;
@@ -228,6 +229,9 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 		if (!head_rev)
 			die(_("Couldn't look up commit object for HEAD"));
 	}
+
+	worktrees = get_worktrees();
+
 	for (i = 0; i < argc; i++, strbuf_reset(&bname)) {
 		char *target = NULL;
 		int flags = 0;
@@ -238,7 +242,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 
 		if (kinds == FILTER_REFS_BRANCHES) {
 			const struct worktree *wt =
-				find_shared_symref("HEAD", name);
+				find_shared_symref(worktrees, "HEAD", name);
 			if (wt) {
 				error(_("Cannot delete branch '%s' "
 					"checked out at '%s'"),
@@ -299,6 +303,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 
 	free(name);
 	strbuf_release(&bname);
+	free_worktrees(worktrees);
 
 	return ret;
 }
diff --git a/builtin/fetch.c b/builtin/fetch.c
index f7abbc31ff..e45185cf9c 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -28,6 +28,7 @@
 #include "promisor-remote.h"
 #include "commit-graph.h"
 #include "shallow.h"
+#include "worktree.h"
 
 #define FORCED_UPDATES_DELAY_WARNING_IN_MS (10 * 1000)
 
@@ -552,7 +553,7 @@ static struct ref *get_ref_map(struct remote *remote,
 		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).");
+		die("--refmap option is only meaningful with command-line refspec(s)");
 	} else {
 		/* Use the defaults */
 		struct branch *branch = branch_get(NULL);
@@ -583,7 +584,7 @@ static struct ref *get_ref_map(struct remote *remote,
 		} else if (!prefetch) {
 			ref_map = get_remote_ref(remote_refs, "HEAD");
 			if (!ref_map)
-				die(_("Couldn't find remote ref HEAD"));
+				die(_("couldn't find remote ref HEAD"));
 			ref_map->fetch_head_status = FETCH_HEAD_MERGE;
 			tail = &ref_map->next;
 		}
@@ -848,13 +849,12 @@ static void format_display(struct strbuf *display, char code,
 
 static int update_local_ref(struct ref *ref,
 			    struct ref_transaction *transaction,
-			    const char *remote,
-			    const struct ref *remote_ref,
-			    struct strbuf *display,
-			    int summary_width)
+			    const char *remote, const struct ref *remote_ref,
+			    struct strbuf *display, int summary_width,
+			    struct worktree **worktrees)
 {
 	struct commit *current = NULL, *updated;
-	struct branch *current_branch = branch_get(NULL);
+	const struct worktree *wt;
 	const char *pretty_ref = prettify_refname(ref->name);
 	int fast_forward = 0;
 
@@ -868,16 +868,17 @@ static int update_local_ref(struct ref *ref,
 		return 0;
 	}
 
-	if (current_branch &&
-	    !strcmp(ref->name, current_branch->name) &&
-	    !(update_head_ok || is_bare_repository()) &&
-	    !is_null_oid(&ref->old_oid)) {
+	if (!update_head_ok &&
+	    (wt = find_shared_symref(worktrees, "HEAD", ref->name)) &&
+	    !wt->is_bare && !is_null_oid(&ref->old_oid)) {
 		/*
 		 * If this is the head, and it's not okay to update
 		 * the head, and the old value of the head isn't empty...
 		 */
 		format_display(display, '!', _("[rejected]"),
-			       _("can't fetch in current branch"),
+			       wt->is_current ?
+				       _("can't fetch in current branch") :
+				       _("checked out in another worktree"),
 			       remote, pretty_ref, summary_width);
 		return 1;
 	}
@@ -1067,16 +1068,17 @@ static void close_fetch_head(struct fetch_head *fetch_head)
 }
 
 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'.");
+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"
+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");
+   "to avoid this check\n");
 
 static int store_updated_refs(const char *raw_url, const char *remote_name,
-			      int connectivity_checked, struct ref *ref_map)
+			      int connectivity_checked, struct ref *ref_map,
+			      struct worktree **worktrees)
 {
 	struct fetch_head fetch_head;
 	int url_len, i, rc = 0;
@@ -1205,7 +1207,8 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 			strbuf_reset(&note);
 			if (ref) {
 				rc |= update_local_ref(ref, transaction, what,
-						       rm, &note, summary_width);
+						       rm, &note, summary_width,
+						       worktrees);
 				free(ref);
 			} else if (write_fetch_head || dry_run) {
 				/*
@@ -1298,7 +1301,9 @@ static int check_exist_and_connected(struct ref *ref_map)
 	return check_connected(iterate_ref_map, &rm, &opt);
 }
 
-static int fetch_and_consume_refs(struct transport *transport, struct ref *ref_map)
+static int fetch_and_consume_refs(struct transport *transport,
+				  struct ref *ref_map,
+				  struct worktree **worktrees)
 {
 	int connectivity_checked = 1;
 	int ret;
@@ -1319,10 +1324,8 @@ static int fetch_and_consume_refs(struct transport *transport, struct ref *ref_m
 	}
 
 	trace2_region_enter("fetch", "consume_refs", the_repository);
-	ret = store_updated_refs(transport->url,
-				 transport->remote->name,
-				 connectivity_checked,
-				 ref_map);
+	ret = store_updated_refs(transport->url, transport->remote->name,
+				 connectivity_checked, ref_map, worktrees);
 	trace2_region_leave("fetch", "consume_refs", the_repository);
 
 out:
@@ -1385,18 +1388,18 @@ static int prune_refs(struct refspec *rs, struct ref *ref_map,
 	return result;
 }
 
-static void check_not_current_branch(struct ref *ref_map)
+static void check_not_current_branch(struct ref *ref_map,
+				     struct worktree **worktrees)
 {
-	struct branch *current_branch = branch_get(NULL);
-
-	if (is_bare_repository() || !current_branch)
-		return;
-
+	const struct worktree *wt;
 	for (; ref_map; ref_map = ref_map->next)
-		if (ref_map->peer_ref && !strcmp(current_branch->refname,
-					ref_map->peer_ref->name))
-			die(_("Refusing to fetch into current branch %s "
-			    "of non-bare repository"), current_branch->refname);
+		if (ref_map->peer_ref &&
+		    (wt = find_shared_symref(worktrees, "HEAD",
+					     ref_map->peer_ref->name)) &&
+		    !wt->is_bare)
+			die(_("refusing to fetch into branch '%s' "
+			      "checked out at '%s'"),
+			    ref_map->peer_ref->name, wt->path);
 }
 
 static int truncate_fetch_head(void)
@@ -1414,10 +1417,10 @@ static void set_option(struct transport *transport, const char *name, const char
 {
 	int r = transport_set_option(transport, name, value);
 	if (r < 0)
-		die(_("Option \"%s\" value \"%s\" is not valid for %s"),
+		die(_("option \"%s\" value \"%s\" is not valid for %s"),
 		    name, value, transport->url);
 	if (r > 0)
-		warning(_("Option \"%s\" is ignored for %s\n"),
+		warning(_("option \"%s\" is ignored for %s\n"),
 			name, transport->url);
 }
 
@@ -1451,7 +1454,7 @@ static void add_negotiation_tips(struct git_transport_options *smart_options)
 		old_nr = oids->nr;
 		for_each_glob_ref(add_oid, s, oids);
 		if (old_nr == oids->nr)
-			warning("Ignoring --negotiation-tip=%s because it does not match any refs",
+			warning("ignoring --negotiation-tip=%s because it does not match any refs",
 				s);
 	}
 	smart_options->negotiation_tips = oids;
@@ -1489,12 +1492,13 @@ static struct transport *prepare_transport(struct remote *remote, int deepen)
 		if (transport->smart_options)
 			add_negotiation_tips(transport->smart_options);
 		else
-			warning("Ignoring --negotiation-tip because the protocol does not support it.");
+			warning("ignoring --negotiation-tip because the protocol does not support it");
 	}
 	return transport;
 }
 
-static void backfill_tags(struct transport *transport, struct ref *ref_map)
+static void backfill_tags(struct transport *transport, struct ref *ref_map,
+			  struct worktree **worktrees)
 {
 	int cannot_reuse;
 
@@ -1515,7 +1519,7 @@ static void backfill_tags(struct transport *transport, struct ref *ref_map)
 	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);
-	fetch_and_consume_refs(transport, ref_map);
+	fetch_and_consume_refs(transport, ref_map, worktrees);
 
 	if (gsecondary) {
 		transport_disconnect(gsecondary);
@@ -1533,6 +1537,7 @@ static int do_fetch(struct transport *transport,
 	struct transport_ls_refs_options transport_ls_refs_options =
 		TRANSPORT_LS_REFS_OPTIONS_INIT;
 	int must_list_refs = 1;
+	struct worktree **worktrees = get_worktrees();
 
 	if (tags == TAGS_DEFAULT) {
 		if (transport->remote->fetch_tags == 2)
@@ -1588,7 +1593,7 @@ static int do_fetch(struct transport *transport,
 	ref_map = get_ref_map(transport->remote, remote_refs, rs,
 			      tags, &autotags);
 	if (!update_head_ok)
-		check_not_current_branch(ref_map);
+		check_not_current_branch(ref_map, worktrees);
 
 	if (tags == TAGS_DEFAULT && autotags)
 		transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, "1");
@@ -1606,7 +1611,7 @@ static int do_fetch(struct transport *transport,
 				   transport->url);
 		}
 	}
-	if (fetch_and_consume_refs(transport, ref_map)) {
+	if (fetch_and_consume_refs(transport, ref_map, worktrees)) {
 		free_refs(ref_map);
 		retcode = 1;
 		goto cleanup;
@@ -1651,11 +1656,11 @@ static int do_fetch(struct transport *transport,
 			else
 				warning(_("unknown branch type"));
 		} else {
-			warning(_("no source branch found.\n"
-				"you need to specify exactly one branch with the --set-upstream option."));
+			warning(_("no source branch found;\n"
+				  "you need to specify exactly one branch with the --set-upstream option"));
 		}
 	}
- skip:
+skip:
 	free_refs(ref_map);
 
 	/* if neither --no-tags nor --tags was specified, do automated tag
@@ -1665,11 +1670,12 @@ static int do_fetch(struct transport *transport,
 		ref_map = NULL;
 		find_non_local_tags(remote_refs, &ref_map, &tail);
 		if (ref_map)
-			backfill_tags(transport, ref_map);
+			backfill_tags(transport, ref_map, worktrees);
 		free_refs(ref_map);
 	}
 
- cleanup:
+cleanup:
+	free_worktrees(worktrees);
 	return retcode;
 }
 
@@ -1790,7 +1796,7 @@ static int fetch_failed_to_start(struct strbuf *out, void *cb, void *task_cb)
 	struct parallel_fetch_state *state = cb;
 	const char *remote = task_cb;
 
-	state->result = error(_("Could not fetch %s"), remote);
+	state->result = error(_("could not fetch %s"), remote);
 
 	return 0;
 }
@@ -1845,7 +1851,7 @@ static int fetch_multiple(struct string_list *list, int max_children)
 			if (verbosity >= 0)
 				printf(_("Fetching %s\n"), name);
 			if (run_command_v_opt(argv.v, RUN_GIT_CMD)) {
-				error(_("Could not fetch %s"), name);
+				error(_("could not fetch %s"), name);
 				result = 1;
 			}
 			strvec_pop(&argv);
@@ -1906,8 +1912,8 @@ static int fetch_one(struct remote *remote, int argc, const char **argv,
 	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."));
+		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);
 
@@ -1942,7 +1948,7 @@ static int fetch_one(struct remote *remote, int argc, const char **argv,
 		if (!strcmp(argv[i], "tag")) {
 			i++;
 			if (i >= argc)
-				die(_("You need to specify a tag name."));
+				die(_("you need to specify a tag name"));
 
 			refspec_appendf(&rs, "refs/tags/%s:refs/tags/%s",
 					argv[i], argv[i]);
@@ -2010,7 +2016,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 
 	if (deepen_relative) {
 		if (deepen_relative < 0)
-			die(_("Negative depth in --deepen is not supported"));
+			die(_("negative depth in --deepen is not supported"));
 		if (depth)
 			die(_("--deepen and --depth are mutually exclusive"));
 		depth = xstrfmt("%d", deepen_relative);
@@ -2047,14 +2053,15 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 		/* 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]);
+				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"));
+				die(_("fetching a group and specifying refspecs does not make sense"));
 		} else {
 			/* Zero or one remotes */
 			remote = remote_get(argv[0]);
@@ -2075,7 +2082,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 		if (gtransport->smart_options) {
 			gtransport->smart_options->acked_commits = &acked_commits;
 		} else {
-			warning(_("Protocol does not support --negotiate-only, exiting."));
+			warning(_("protocol does not support --negotiate-only, exiting"));
 			return 1;
 		}
 		if (server_options.nr)
diff --git a/builtin/notes.c b/builtin/notes.c
index 85d1abad88..118db9e455 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -860,15 +860,19 @@ static int merge(int argc, const char **argv, const char *prefix)
 		update_ref(msg.buf, default_notes_ref(), &result_oid, NULL, 0,
 			   UPDATE_REFS_DIE_ON_ERR);
 	else { /* Merge has unresolved conflicts */
+		struct worktree **worktrees;
 		const struct worktree *wt;
 		/* Update .git/NOTES_MERGE_PARTIAL with partial merge result */
 		update_ref(msg.buf, "NOTES_MERGE_PARTIAL", &result_oid, NULL,
 			   0, UPDATE_REFS_DIE_ON_ERR);
 		/* Store ref-to-be-updated into .git/NOTES_MERGE_REF */
-		wt = find_shared_symref("NOTES_MERGE_REF", default_notes_ref());
+		worktrees = get_worktrees();
+		wt = find_shared_symref(worktrees, "NOTES_MERGE_REF",
+					default_notes_ref());
 		if (wt)
 			die(_("a notes merge into %s is already in-progress at %s"),
 			    default_notes_ref(), wt->path);
+		free_worktrees(worktrees);
 		if (create_symref("NOTES_MERGE_REF", default_notes_ref(), NULL))
 			die(_("failed to store link to current notes ref (%s)"),
 			    default_notes_ref());
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 07a3053c1d..4f92e6f059 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -175,7 +175,7 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
 			strbuf_addf(&fsck_msg_types, "%c%s=%s",
 				fsck_msg_types.len ? ',' : '=', var, value);
 		else
-			warning("Skipping unknown msg id '%s'", var);
+			warning("skipping unknown msg id '%s'", var);
 		return 0;
 	}
 
@@ -1434,29 +1434,22 @@ static const char *push_to_checkout(unsigned char *hash,
 
 static const char *update_worktree(unsigned char *sha1, const struct worktree *worktree)
 {
-	const char *retval, *work_tree, *git_dir = NULL;
+	const char *retval, *git_dir;
 	struct strvec env = STRVEC_INIT;
 
-	if (worktree && worktree->path)
-		work_tree = worktree->path;
-	else if (git_work_tree_cfg)
-		work_tree = git_work_tree_cfg;
-	else
-		work_tree = "..";
+	if (!worktree || !worktree->path)
+		BUG("worktree->path must be non-NULL");
 
-	if (is_bare_repository())
+	if (worktree->is_bare)
 		return "denyCurrentBranch = updateInstead needs a worktree";
-	if (worktree)
-		git_dir = get_worktree_git_dir(worktree);
-	if (!git_dir)
-		git_dir = get_git_dir();
+	git_dir = get_worktree_git_dir(worktree);
 
 	strvec_pushf(&env, "GIT_DIR=%s", absolute_path(git_dir));
 
 	if (!hook_exists(push_to_checkout_hook))
-		retval = push_to_deploy(sha1, &env, work_tree);
+		retval = push_to_deploy(sha1, &env, worktree->path);
 	else
-		retval = push_to_checkout(sha1, &env, work_tree);
+		retval = push_to_checkout(sha1, &env, worktree->path);
 
 	strvec_clear(&env);
 	return retval;
@@ -1471,19 +1464,22 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 	struct object_id *old_oid = &cmd->old_oid;
 	struct object_id *new_oid = &cmd->new_oid;
 	int do_update_worktree = 0;
-	const struct worktree *worktree = is_bare_repository() ? NULL : find_shared_symref("HEAD", name);
+	struct worktree **worktrees = get_worktrees();
+	const struct worktree *worktree =
+		find_shared_symref(worktrees, "HEAD", name);
 
 	/* only refs/... are allowed */
 	if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
 		rp_error("refusing to create funny ref '%s' remotely", name);
-		return "funny refname";
+		ret = "funny refname";
+		goto out;
 	}
 
 	strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name);
 	free(namespaced_name);
 	namespaced_name = strbuf_detach(&namespaced_name_buf, NULL);
 
-	if (worktree) {
+	if (worktree && !worktree->is_bare) {
 		switch (deny_current_branch) {
 		case DENY_IGNORE:
 			break;
@@ -1495,7 +1491,8 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 			rp_error("refusing to update checked out branch: %s", name);
 			if (deny_current_branch == DENY_UNCONFIGURED)
 				refuse_unconfigured_deny();
-			return "branch is currently checked out";
+			ret = "branch is currently checked out";
+			goto out;
 		case DENY_UPDATE_INSTEAD:
 			/* pass -- let other checks intervene first */
 			do_update_worktree = 1;
@@ -1506,13 +1503,15 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 	if (!is_null_oid(new_oid) && !has_object_file(new_oid)) {
 		error("unpack should have generated %s, "
 		      "but I can't find it!", oid_to_hex(new_oid));
-		return "bad pack";
+		ret = "bad pack";
+		goto out;
 	}
 
 	if (!is_null_oid(old_oid) && is_null_oid(new_oid)) {
 		if (deny_deletes && starts_with(name, "refs/heads/")) {
 			rp_error("denying ref deletion for %s", name);
-			return "deletion prohibited";
+			ret = "deletion prohibited";
+			goto out;
 		}
 
 		if (worktree || (head_name && !strcmp(namespaced_name, head_name))) {
@@ -1528,9 +1527,11 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 				if (deny_delete_current == DENY_UNCONFIGURED)
 					refuse_unconfigured_deny_delete_current();
 				rp_error("refusing to delete the current branch: %s", name);
-				return "deletion of the current branch prohibited";
+				ret = "deletion of the current branch prohibited";
+				goto out;
 			default:
-				return "Invalid denyDeleteCurrent setting";
+				ret = "Invalid denyDeleteCurrent setting";
+				goto out;
 			}
 		}
 	}
@@ -1548,25 +1549,28 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		    old_object->type != OBJ_COMMIT ||
 		    new_object->type != OBJ_COMMIT) {
 			error("bad sha1 objects for %s", name);
-			return "bad ref";
+			ret = "bad ref";
+			goto out;
 		}
 		old_commit = (struct commit *)old_object;
 		new_commit = (struct commit *)new_object;
 		if (!in_merge_bases(old_commit, new_commit)) {
 			rp_error("denying non-fast-forward %s"
 				 " (you should pull first)", name);
-			return "non-fast-forward";
+			ret = "non-fast-forward";
+			goto out;
 		}
 	}
 	if (run_update_hook(cmd)) {
 		rp_error("hook declined to update %s", name);
-		return "hook declined";
+		ret = "hook declined";
+		goto out;
 	}
 
 	if (do_update_worktree) {
-		ret = update_worktree(new_oid->hash, find_shared_symref("HEAD", name));
+		ret = update_worktree(new_oid->hash, worktree);
 		if (ret)
-			return ret;
+			goto out;
 	}
 
 	if (is_null_oid(new_oid)) {
@@ -1574,9 +1578,9 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		if (!parse_object(the_repository, old_oid)) {
 			old_oid = NULL;
 			if (ref_exists(name)) {
-				rp_warning("Allowing deletion of corrupt ref.");
+				rp_warning("allowing deletion of corrupt ref");
 			} else {
-				rp_warning("Deleting a non-existent ref.");
+				rp_warning("deleting a non-existent ref");
 				cmd->did_not_exist = 1;
 			}
 		}
@@ -1585,17 +1589,19 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 					   old_oid,
 					   0, "push", &err)) {
 			rp_error("%s", err.buf);
-			strbuf_release(&err);
-			return "failed to delete";
+			ret = "failed to delete";
+		} else {
+			ret = NULL; /* good */
 		}
 		strbuf_release(&err);
-		return NULL; /* good */
 	}
 	else {
 		struct strbuf err = STRBUF_INIT;
 		if (shallow_update && si->shallow_ref[cmd->index] &&
-		    update_shallow_ref(cmd, si))
-			return "shallow error";
+		    update_shallow_ref(cmd, si)) {
+			ret = "shallow error";
+			goto out;
+		}
 
 		if (ref_transaction_update(transaction,
 					   namespaced_name,
@@ -1603,14 +1609,16 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 					   0, "push",
 					   &err)) {
 			rp_error("%s", err.buf);
-			strbuf_release(&err);
-
-			return "failed to update ref";
+			ret = "failed to update ref";
+		} else {
+			ret = NULL; /* good */
 		}
 		strbuf_release(&err);
-
-		return NULL; /* good */
 	}
+
+out:
+	free_worktrees(worktrees);
+	return ret;
 }
 
 static void run_update_post_hook(struct command *commands)
@@ -2476,9 +2484,9 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, options, receive_pack_usage, 0);
 
 	if (argc > 1)
-		usage_msg_opt(_("Too many arguments."), receive_pack_usage, options);
+		usage_msg_opt(_("too many arguments"), receive_pack_usage, options);
 	if (argc == 0)
-		usage_msg_opt(_("You must specify a directory."), receive_pack_usage, options);
+		usage_msg_opt(_("you must specify a directory"), receive_pack_usage, options);
 
 	service_dir = argv[0];
 
diff --git a/t/t2018-checkout-branch.sh b/t/t2018-checkout-branch.sh
index 93be1c0eae..3e93506c04 100755
--- a/t/t2018-checkout-branch.sh
+++ b/t/t2018-checkout-branch.sh
@@ -148,7 +148,7 @@ test_expect_success 'checkout -b to an existing branch fails' '
 test_expect_success 'checkout -b to @{-1} fails with the right branch name' '
 	git checkout branch1 &&
 	git checkout branch2 &&
-	echo  >expect "fatal: A branch named '\''branch1'\'' already exists." &&
+	echo  >expect "fatal: a branch named '\''branch1'\'' already exists" &&
 	test_must_fail git checkout -b @{-1} 2>actual &&
 	test_cmp expect actual
 '
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 8c5c1ccf33..8a619d785e 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -168,6 +168,13 @@ test_expect_success 'git branch -M foo bar should fail when bar is checked out'
 	test_must_fail git branch -M bar foo
 '
 
+test_expect_success 'git branch -M foo bar should fail when bar is checked out in worktree' '
+	git branch -f bar &&
+	test_when_finished "git worktree remove wt && git branch -D wt" &&
+	git worktree add wt &&
+	test_must_fail git branch -M bar wt
+'
+
 test_expect_success 'git branch -M baz bam should succeed when baz is checked out' '
 	git checkout -b baz &&
 	git branch bam &&
@@ -888,7 +895,7 @@ test_expect_success '--set-upstream-to fails on a missing src branch' '
 '
 
 test_expect_success '--set-upstream-to fails on a non-ref' '
-	echo "fatal: Cannot setup tracking information; starting point '"'"'HEAD^{}'"'"' is not a branch." >expect &&
+	echo "fatal: cannot set up tracking information; starting point '"'"'HEAD^{}'"'"' is not a branch" >expect &&
 	test_must_fail git branch --set-upstream-to HEAD^{} 2>err &&
 	test_cmp expect err
 '
@@ -975,7 +982,7 @@ test_expect_success 'disabled option --set-upstream fails' '
 test_expect_success '--set-upstream-to notices an error to set branch as own upstream' '
 	git branch --set-upstream-to refs/heads/my13 my13 2>actual &&
 	cat >expect <<-\EOF &&
-	warning: Not setting branch my13 as its own upstream.
+	warning: not setting branch my13 as its own upstream
 	EOF
 	test_expect_code 1 git config branch.my13.remote &&
 	test_expect_code 1 git config branch.my13.merge &&
diff --git a/t/t5504-fetch-receive-strict.sh b/t/t5504-fetch-receive-strict.sh
index 6e5a9c20e7..b0b795aca9 100755
--- a/t/t5504-fetch-receive-strict.sh
+++ b/t/t5504-fetch-receive-strict.sh
@@ -292,7 +292,7 @@ test_expect_success 'push with receive.fsck.missingEmail=warn' '
 		receive.fsck.missingEmail warn &&
 	git push --porcelain dst bogus >act 2>&1 &&
 	grep "missingEmail" act &&
-	test_i18ngrep "Skipping unknown msg id.*whatever" act &&
+	test_i18ngrep "skipping unknown msg id.*whatever" act &&
 	git --git-dir=dst/.git branch -D bogus &&
 	git --git-dir=dst/.git config --add \
 		receive.fsck.missingEmail ignore &&
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 7831a38dde..837a49642a 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1778,6 +1778,38 @@ test_expect_success 'denyCurrentBranch and worktrees' '
 	test_must_fail git -C cloned push origin HEAD:new-wt &&
 	test_config receive.denyCurrentBranch updateInstead &&
 	git -C cloned push origin HEAD:new-wt &&
+	test_path_exists new-wt/first.t &&
 	test_must_fail git -C cloned push --delete origin new-wt
 '
+
+test_expect_success 'denyCurrentBranch and bare repository worktrees' '
+	test_when_finished "rm -fr bare.git" &&
+	git clone --bare . bare.git &&
+	git -C bare.git worktree add wt &&
+	test_commit grape &&
+	git -C bare.git config receive.denyCurrentBranch refuse &&
+	test_must_fail git push bare.git HEAD:wt &&
+	git -C bare.git config receive.denyCurrentBranch updateInstead &&
+	git push bare.git HEAD:wt &&
+	test_path_exists bare.git/wt/grape.t &&
+	test_must_fail git push --delete bare.git wt
+'
+
+test_expect_success 'refuse fetch to current branch of worktree' '
+	test_when_finished "git worktree remove --force wt && git branch -D wt" &&
+	git worktree add wt &&
+	test_commit apple &&
+	test_must_fail git fetch . HEAD:wt &&
+	git fetch -u . HEAD:wt
+'
+
+test_expect_success 'refuse fetch to current branch of bare repository worktree' '
+	test_when_finished "rm -fr bare.git" &&
+	git clone --bare . bare.git &&
+	git -C bare.git worktree add wt &&
+	test_commit banana &&
+	test_must_fail git -C bare.git fetch .. HEAD:wt &&
+	git -C bare.git fetch -u .. HEAD:wt
+'
+
 test_done
diff --git a/worktree.c b/worktree.c
index 2c155b1015..6f598dcfcd 100644
--- a/worktree.c
+++ b/worktree.c
@@ -404,17 +404,13 @@ int is_worktree_being_bisected(const struct worktree *wt,
  * bisect). New commands that do similar things should update this
  * function as well.
  */
-const struct worktree *find_shared_symref(const char *symref,
+const struct worktree *find_shared_symref(struct worktree **worktrees,
+					  const char *symref,
 					  const char *target)
 {
 	const struct worktree *existing = NULL;
-	static struct worktree **worktrees;
 	int i = 0;
 
-	if (worktrees)
-		free_worktrees(worktrees);
-	worktrees = get_worktrees();
-
 	for (i = 0; worktrees[i]; i++) {
 		struct worktree *wt = worktrees[i];
 		const char *symref_target;
diff --git a/worktree.h b/worktree.h
index 8b7c408132..9e06fcbdf3 100644
--- a/worktree.h
+++ b/worktree.h
@@ -143,9 +143,10 @@ void free_worktrees(struct worktree **);
 /*
  * Check if a per-worktree symref points to a ref in the main worktree
  * or any linked worktree, and return the worktree that holds the ref,
- * or NULL otherwise. The result may be destroyed by the next call.
+ * or NULL otherwise.
  */
-const struct worktree *find_shared_symref(const char *symref,
+const struct worktree *find_shared_symref(struct worktree **worktrees,
+					  const char *symref,
 					  const char *target);
 
 /*