Merge branch 'rj/branch-in-use-error-message'

A message written in olden time prevented a branch from getting
checked out saying it is already checked out elsewhere, but these
days, we treat a branch that is being bisected or rebased just like
a branch that is checked out and protect it.  Rephrase the message
to say that the branch is in use.

* rj/branch-in-use-error-message:
  branch: error message checking out a branch in use
  branch: error message deleting a branch in use

branch.c

@@ -838,7 +838,7 @@ void die_if_checked_out(const char *branch, int ignore_current_worktree)
 
 		if (is_shared_symref(worktrees[i], "HEAD", branch)) {
 			skip_prefix(branch, "refs/heads/", &branch);
-			die(_("'%s' is already checked out at '%s'"),
+			die(_("'%s' is already used by worktree at '%s'"),
 				branch, worktrees[i]->path);
 		}
 	}

builtin/branch.c

@@ -261,7 +261,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 			const char *path;
 			if ((path = branch_checked_out(name))) {
 				error(_("Cannot delete branch '%s' "
-					"checked out at '%s'"),
+					"used by worktree at '%s'"),
 				      bname.buf, path);
 				ret = 1;
 				continue;

t/t2400-worktree-add.sh

@@ -121,7 +121,8 @@ test_expect_success '"add" worktree creating new branch' '
 test_expect_success 'die the same branch is already checked out' '
 	(
 		cd here &&
-		test_must_fail git checkout newmain
+		test_must_fail git checkout newmain 2>actual &&
+		grep "already used by worktree at" actual
 	)
 '
 

t/t3200-branch.sh

@@ -942,7 +942,19 @@ test_expect_success 'test deleting branch without config' '
 test_expect_success 'deleting currently checked out branch fails' '
 	git worktree add -b my7 my7 &&
 	test_must_fail git -C my7 branch -d my7 &&
-	test_must_fail git branch -d my7 &&
+	test_must_fail git branch -d my7 2>actual &&
+	grep "^error: Cannot delete branch .my7. used by worktree at " actual &&
+	rm -r my7 &&
+	git worktree prune
+'
+
+test_expect_success 'deleting in-use branch fails' '
+	git worktree add my7 &&
+	test_commit -C my7 bt7 &&
+	git -C my7 bisect start HEAD HEAD~2 &&
+	test_must_fail git -C my7 branch -d my7 &&
+	test_must_fail git branch -d my7 2>actual &&
+	grep "^error: Cannot delete branch .my7. used by worktree at " actual &&
 	rm -r my7 &&
 	git worktree prune
 '

t/t3400-rebase.sh

@@ -421,7 +421,7 @@ test_expect_success 'refuse to switch to branch checked out elsewhere' '
 	git checkout main &&
 	git worktree add wt &&
 	test_must_fail git -C wt rebase main main 2>err &&
-	test_i18ngrep "already checked out" err
+	test_i18ngrep "already used by worktree at" err
 '
 
 test_expect_success MINGW,SYMLINKS_WINDOWS 'rebase when .git/logs is a symlink' '