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

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,

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;
 }