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

1 files changed, 104 insertions, 18 deletions

diff --git a/worktree.c b/worktree.c
index 89ebe67a50..199b1ef94b 100644
--- a/worktree.c
+++ b/worktree.c
@@ -2,6 +2,8 @@
 #include "refs.h"
 #include "strbuf.h"
 #include "worktree.h"
+#include "dir.h"
+#include "wt-status.h"
 
 void free_worktrees(struct worktree **worktrees)
 {
@@ -9,7 +11,7 @@ void free_worktrees(struct worktree **worktrees)
 
 	for (i = 0; worktrees[i]; i++) {
 		free(worktrees[i]->path);
-		free(worktrees[i]->git_dir);
+		free(worktrees[i]->id);
 		free(worktrees[i]->head_ref);
 		free(worktrees[i]);
 	}
@@ -74,13 +76,11 @@ static struct worktree *get_main_worktree(void)
 	struct worktree *worktree = NULL;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf worktree_path = STRBUF_INIT;
-	struct strbuf gitdir = STRBUF_INIT;
 	struct strbuf head_ref = STRBUF_INIT;
 	int is_bare = 0;
 	int is_detached = 0;
 
-	strbuf_addf(&gitdir, "%s", absolute_path(get_git_common_dir()));
-	strbuf_addbuf(&worktree_path, &gitdir);
+	strbuf_addstr(&worktree_path, absolute_path(get_git_common_dir()));
 	is_bare = !strbuf_strip_suffix(&worktree_path, "/.git");
 	if (is_bare)
 		strbuf_strip_suffix(&worktree_path, "/.");
@@ -92,15 +92,15 @@ static struct worktree *get_main_worktree(void)
 
 	worktree = xmalloc(sizeof(struct worktree));
 	worktree->path = strbuf_detach(&worktree_path, NULL);
-	worktree->git_dir = strbuf_detach(&gitdir, NULL);
+	worktree->id = NULL;
 	worktree->is_bare = is_bare;
 	worktree->head_ref = NULL;
 	worktree->is_detached = is_detached;
+	worktree->is_current = 0;
 	add_head_info(&head_ref, worktree);
 
 done:
 	strbuf_release(&path);
-	strbuf_release(&gitdir);
 	strbuf_release(&worktree_path);
 	strbuf_release(&head_ref);
 	return worktree;
@@ -111,16 +111,13 @@ static struct worktree *get_linked_worktree(const char *id)
 	struct worktree *worktree = NULL;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf worktree_path = STRBUF_INIT;
-	struct strbuf gitdir = STRBUF_INIT;
 	struct strbuf head_ref = STRBUF_INIT;
 	int is_detached = 0;
 
 	if (!id)
 		die("Missing linked worktree name");
 
-	strbuf_addf(&gitdir, "%s/worktrees/%s",
-			absolute_path(get_git_common_dir()), id);
-	strbuf_addf(&path, "%s/gitdir", gitdir.buf);
+	strbuf_git_common_path(&path, "worktrees/%s/gitdir", id);
 	if (strbuf_read_file(&worktree_path, path.buf, 0) <= 0)
 		/* invalid gitdir file */
 		goto done;
@@ -140,20 +137,39 @@ static struct worktree *get_linked_worktree(const char *id)
 
 	worktree = xmalloc(sizeof(struct worktree));
 	worktree->path = strbuf_detach(&worktree_path, NULL);
-	worktree->git_dir = strbuf_detach(&gitdir, NULL);
+	worktree->id = xstrdup(id);
 	worktree->is_bare = 0;
 	worktree->head_ref = NULL;
 	worktree->is_detached = is_detached;
+	worktree->is_current = 0;
 	add_head_info(&head_ref, worktree);
 
 done:
 	strbuf_release(&path);
-	strbuf_release(&gitdir);
 	strbuf_release(&worktree_path);
 	strbuf_release(&head_ref);
 	return worktree;
 }
 
+static void mark_current_worktree(struct worktree **worktrees)
+{
+	struct strbuf git_dir = STRBUF_INIT;
+	struct strbuf path = STRBUF_INIT;
+	int i;
+
+	strbuf_addstr(&git_dir, absolute_path(get_git_dir()));
+	for (i = 0; worktrees[i]; i++) {
+		struct worktree *wt = worktrees[i];
+		strbuf_addstr(&path, absolute_path(get_worktree_git_dir(wt)));
+		wt->is_current = !fspathcmp(git_dir.buf, path.buf);
+		strbuf_reset(&path);
+		if (wt->is_current)
+			break;
+	}
+	strbuf_release(&git_dir);
+	strbuf_release(&path);
+}
+
 struct worktree **get_worktrees(void)
 {
 	struct worktree **list = NULL;
@@ -185,35 +201,105 @@ struct worktree **get_worktrees(void)
 	}
 	ALLOC_GROW(list, counter + 1, alloc);
 	list[counter] = NULL;
+
+	mark_current_worktree(list);
 	return list;
 }
 
-char *find_shared_symref(const char *symref, const char *target)
+const char *get_worktree_git_dir(const struct worktree *wt)
+{
+	if (!wt)
+		return get_git_dir();
+	else if (!wt->id)
+		return get_git_common_dir();
+	else
+		return git_common_path("worktrees/%s", wt->id);
+}
+
+int is_worktree_being_rebased(const struct worktree *wt,
+			      const char *target)
+{
+	struct wt_status_state state;
+	int found_rebase;
+
+	memset(&state, 0, sizeof(state));
+	found_rebase = wt_status_check_rebase(wt, &state) &&
+		((state.rebase_in_progress ||
+		  state.rebase_interactive_in_progress) &&
+		 state.branch &&
+		 starts_with(target, "refs/heads/") &&
+		 !strcmp(state.branch, target + strlen("refs/heads/")));
+	free(state.branch);
+	free(state.onto);
+	return found_rebase;
+}
+
+int is_worktree_being_bisected(const struct worktree *wt,
+			       const char *target)
 {
-	char *existing = NULL;
+	struct wt_status_state state;
+	int found_rebase;
+
+	memset(&state, 0, sizeof(state));
+	found_rebase = wt_status_check_bisect(wt, &state) &&
+		state.branch &&
+		starts_with(target, "refs/heads/") &&
+		!strcmp(state.branch, target + strlen("refs/heads/"));
+	free(state.branch);
+	return found_rebase;
+}
+
+/*
+ * note: this function should be able to detect shared symref even if
+ * HEAD is temporarily detached (e.g. in the middle of rebase or
+ * bisect). New commands that do similar things should update this
+ * function as well.
+ */
+const struct worktree *find_shared_symref(const char *symref,
+					  const char *target)
+{
+	const struct worktree *existing = NULL;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
-	struct worktree **worktrees = get_worktrees();
+	static struct worktree **worktrees;
 	int i = 0;
 
+	if (worktrees)
+		free_worktrees(worktrees);
+	worktrees = get_worktrees();
+
 	for (i = 0; worktrees[i]; i++) {
+		struct worktree *wt = worktrees[i];
+
+		if (wt->is_detached && !strcmp(symref, "HEAD")) {
+			if (is_worktree_being_rebased(wt, target)) {
+				existing = wt;
+				break;
+			}
+			if (is_worktree_being_bisected(wt, target)) {
+				existing = wt;
+				break;
+			}
+		}
+
 		strbuf_reset(&path);
 		strbuf_reset(&sb);
-		strbuf_addf(&path, "%s/%s", worktrees[i]->git_dir, symref);
+		strbuf_addf(&path, "%s/%s",
+			    get_worktree_git_dir(wt),
+			    symref);
 
 		if (parse_ref(path.buf, &sb, NULL)) {
 			continue;
 		}
 
 		if (!strcmp(sb.buf, target)) {
-			existing = xstrdup(worktrees[i]->path);
+			existing = wt;
 			break;
 		}
 	}
 
 	strbuf_release(&path);
 	strbuf_release(&sb);
-	free_worktrees(worktrees);
 
 	return existing;
 }