Merge branch 'rj/avoid-switching-to-already-used-branch'

A few subcommands have been taught to stop users from working on a
branch that is being used in another worktree linked to the same
repository.

* rj/avoid-switching-to-already-used-branch:
  switch: reject if the branch is already checked out elsewhere (test)
  rebase: refuse to switch to a branch already checked out elsewhere (test)
  branch: fix die_if_checked_out() when ignore_current_worktree
  worktree: introduce is_shared_symref()

1 files changed, 9 insertions, 5 deletions

diff --git a/branch.c b/branch.c
index 5aaf073dce..eacef62b7c 100644
--- a/branch.c
+++ b/branch.c
@@ -821,12 +821,16 @@ 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(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);
+	for (int i = 0; worktrees[i]; i++) {
+		if (worktrees[i]->is_current && ignore_current_worktree)
+			continue;
+
+		if (is_shared_symref(worktrees[i], "HEAD", branch)) {
+			skip_prefix(branch, "refs/heads/", &branch);
+			die(_("'%s' is already checked out at '%s'"),
+				branch, worktrees[i]->path);
+		}
 	}
 
 	free_worktrees(worktrees);