Merge branch 'nd/worktree-various-heads'

The experimental "multiple worktree" feature gains more safety to
forbid operations on a branch that is checked out or being actively
worked on elsewhere, by noticing that e.g. it is being rebased.

* nd/worktree-various-heads:
  branch: do not rename a branch under bisect or rebase
  worktree.c: check whether branch is bisected in another worktree
  wt-status.c: split bisect detection out of wt_status_get_state()
  worktree.c: check whether branch is rebased in another worktree
  worktree.c: avoid referencing to worktrees[i] multiple times
  wt-status.c: make wt_status_check_rebase() work on any worktree
  wt-status.c: split rebase detection out of wt_status_get_state()
  path.c: refactor and add worktree_git_path()
  worktree.c: mark current worktree
  worktree.c: make find_shared_symref() return struct worktree *
  worktree.c: store "id" instead of "git_dir"
  path.c: add git_common_path() and strbuf_git_common_path()
  dir.c: rename str(n)cmp_icase to fspath(n)cmp

4 files changed, 36 insertions, 11 deletions

diff --git a/builtin/branch.c b/builtin/branch.c
index eacec57593..2ecde53bf8 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -220,12 +220,12 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 		name = mkpathdup(fmt, bname.buf);
 
 		if (kinds == FILTER_REFS_BRANCHES) {
-			char *worktree = find_shared_symref("HEAD", name);
-			if (worktree) {
+			const struct worktree *wt =
+				find_shared_symref("HEAD", name);
+			if (wt) {
 				error(_("Cannot delete branch '%s' "
 					"checked out at '%s'"),
-				      bname.buf, worktree);
-				free(worktree);
+				      bname.buf, wt->path);
 				ret = 1;
 				continue;
 			}
@@ -526,6 +526,29 @@ static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sortin
 	ref_array_clear(&array);
 }
 
+static void reject_rebase_or_bisect_branch(const char *target)
+{
+	struct worktree **worktrees = get_worktrees();
+	int i;
+
+	for (i = 0; worktrees[i]; i++) {
+		struct worktree *wt = worktrees[i];
+
+		if (!wt->is_detached)
+			continue;
+
+		if (is_worktree_being_rebased(wt, target))
+			die(_("Branch %s is being rebased at %s"),
+			    target, wt->path);
+
+		if (is_worktree_being_bisected(wt, target))
+			die(_("Branch %s is being bisected at %s"),
+			    target, wt->path);
+	}
+
+	free_worktrees(worktrees);
+}
+
 static void rename_branch(const char *oldname, const char *newname, int force)
 {
 	struct strbuf oldref = STRBUF_INIT, newref = STRBUF_INIT, logmsg = STRBUF_INIT;
@@ -555,6 +578,8 @@ static void rename_branch(const char *oldname, const char *newname, int force)
 
 	validate_new_branchname(newname, &newref, force, clobber_head_ok);
 
+	reject_rebase_or_bisect_branch(oldref.buf);
+
 	strbuf_addf(&logmsg, "Branch: renamed %s to %s",
 		 oldref.buf, newref.buf);
 
diff --git a/builtin/checkout.c b/builtin/checkout.c
index ea2fe1cf3f..3398c61e9a 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1110,7 +1110,7 @@ static int checkout_branch(struct checkout_opts *opts,
 		char *head_ref = resolve_refdup("HEAD", 0, sha1, &flag);
 		if (head_ref &&
 		    (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
-			die_if_checked_out(new->path);
+			die_if_checked_out(new->path, 1);
 		free(head_ref);
 	}
 
diff --git a/builtin/notes.c b/builtin/notes.c
index 6fd058de92..c65b59ad9a 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -847,15 +847,15 @@ static int merge(int argc, const char **argv, const char *prefix)
 		update_ref(msg.buf, default_notes_ref(), result_sha1, NULL,
 			   0, UPDATE_REFS_DIE_ON_ERR);
 	else { /* Merge has unresolved conflicts */
-		char *existing;
+		const struct worktree *wt;
 		/* Update .git/NOTES_MERGE_PARTIAL with partial merge result */
 		update_ref(msg.buf, "NOTES_MERGE_PARTIAL", result_sha1, NULL,
 			   0, UPDATE_REFS_DIE_ON_ERR);
 		/* Store ref-to-be-updated into .git/NOTES_MERGE_REF */
-		existing = find_shared_symref("NOTES_MERGE_REF", default_notes_ref());
-		if (existing)
+		wt = find_shared_symref("NOTES_MERGE_REF", default_notes_ref());
+		if (wt)
 			die(_("A notes merge into %s is already in-progress at %s"),
-			    default_notes_ref(), existing);
+			    default_notes_ref(), wt->path);
 		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/worktree.c b/builtin/worktree.c
index 331ecf6761..96a2834a18 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -205,7 +205,7 @@ static int add_worktree(const char *path, const char *refname,
 	if (!opts->detach && !strbuf_check_branch_ref(&symref, refname) &&
 		 ref_exists(symref.buf)) { /* it's a branch */
 		if (!opts->force)
-			die_if_checked_out(symref.buf);
+			die_if_checked_out(symref.buf, 0);
 	} else { /* must be a commit */
 		commit = lookup_commit_reference_by_name(refname);
 		if (!commit)
@@ -349,7 +349,7 @@ static int add(int ac, const char **av, const char *prefix)
 		if (!opts.force &&
 		    !strbuf_check_branch_ref(&symref, opts.new_branch) &&
 		    ref_exists(symref.buf))
-			die_if_checked_out(symref.buf);
+			die_if_checked_out(symref.buf, 0);
 		strbuf_release(&symref);
 	}