branch: check for bisects and rebases

The branch_checked_out() helper was added by the previous change, but it
used an over-simplified view to check if a branch is checked out. It
only focused on the HEAD symref, but ignored whether a bisect or rebase
was happening.

Teach branch_checked_out() to check for these things, and also add tests
to ensure that we do not lose this functionality in the future.

Now that this test coverage exists, we can safely refactor
validate_new_branchname() to use branch_checked_out().

Note that we need to prepend "refs/heads/" to the 'state.branch' after
calling wt_status_check_*(). We also need to duplicate wt->path so the
value is not freed at the end of the call.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

branch.c

@@ -362,6 +362,7 @@ static void prepare_checked_out_branches(void)
 	worktrees = get_worktrees();
 
 	while (worktrees[i]) {
+		struct wt_status_state state = { 0 };
 		struct worktree *wt = worktrees[i++];
 
 		if (wt->is_bare)
@@ -371,6 +372,29 @@ static void prepare_checked_out_branches(void)
 			strmap_put(&current_checked_out_branches,
 				   wt->head_ref,
 				   xstrdup(wt->path));
+
+		if (wt_status_check_rebase(wt, &state) &&
+		    (state.rebase_in_progress || state.rebase_interactive_in_progress) &&
+		    state.branch) {
+			struct strbuf ref = STRBUF_INIT;
+			strbuf_addf(&ref, "refs/heads/%s", state.branch);
+			strmap_put(&current_checked_out_branches,
+				   ref.buf,
+				   xstrdup(wt->path));
+			strbuf_release(&ref);
+		}
+		wt_status_state_free_buffers(&state);
+
+		if (wt_status_check_bisect(wt, &state) &&
+		    state.branch) {
+			struct strbuf ref = STRBUF_INIT;
+			strbuf_addf(&ref, "refs/heads/%s", state.branch);
+			strmap_put(&current_checked_out_branches,
+				   ref.buf,
+				   xstrdup(wt->path));
+			strbuf_release(&ref);
+		}
+		wt_status_state_free_buffers(&state);
 	}
 
 	free_worktrees(worktrees);
@@ -390,9 +414,7 @@ const char *branch_checked_out(const char *refname)
  */
 int validate_new_branchname(const char *name, struct strbuf *ref, int force)
 {
-	struct worktree **worktrees;
-	const struct worktree *wt;
-
+	const char *path;
 	if (!validate_branchname(name, ref))
 		return 0;
 
@@ -400,13 +422,10 @@ int validate_new_branchname(const char *name, struct strbuf *ref, int force)
 		die(_("a branch named '%s' already exists"),
 		    ref->buf + strlen("refs/heads/"));
 
-	worktrees = get_worktrees();
-	wt = find_shared_symref(worktrees, "HEAD", ref->buf);
-	if (wt && !wt->is_bare)
+	if ((path = branch_checked_out(ref->buf)))
 		die(_("cannot force update the branch '%s' "
 		      "checked out at '%s'"),
-		    ref->buf + strlen("refs/heads/"), wt->path);
-	free_worktrees(worktrees);
+		    ref->buf + strlen("refs/heads/"), path);
 
 	return 1;
 }

t/t2407-worktree-heads.sh

@@ -26,4 +26,26 @@ test_expect_success 'refuse to overwrite: checked out in worktree' '
 	done
 '
 
+test_expect_success 'refuse to overwrite: worktree in bisect' '
+	test_when_finished rm -rf .git/worktrees/wt-*/BISECT_* &&
+
+	touch .git/worktrees/wt-4/BISECT_LOG &&
+	echo refs/heads/fake-2 >.git/worktrees/wt-4/BISECT_START &&
+
+	test_must_fail git branch -f fake-2 HEAD 2>err &&
+	grep "cannot force update the branch '\''fake-2'\'' checked out at.*wt-4" err
+'
+
+test_expect_success 'refuse to overwrite: worktree in rebase' '
+	test_when_finished rm -rf .git/worktrees/wt-*/rebase-merge &&
+
+	mkdir -p .git/worktrees/wt-3/rebase-merge &&
+	touch .git/worktrees/wt-3/rebase-merge/interactive &&
+	echo refs/heads/fake-1 >.git/worktrees/wt-3/rebase-merge/head-name &&
+	echo refs/heads/fake-2 >.git/worktrees/wt-3/rebase-merge/onto &&
+
+	test_must_fail git branch -f fake-1 HEAD 2>err &&
+	grep "cannot force update the branch '\''fake-1'\'' checked out at.*wt-3" err
+'
+
 test_done