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

path.c

@@ -5,6 +5,7 @@
 #include "strbuf.h"
 #include "string-list.h"
 #include "dir.h"
+#include "worktree.h"
 
 static int get_st_mode_bits(const char *path, int *mode)
 {
@@ -383,10 +384,11 @@ static void adjust_git_path(struct strbuf *buf, int git_dir_len)
 		update_common_dir(buf, git_dir_len, NULL);
 }
 
-static void do_git_path(struct strbuf *buf, const char *fmt, va_list args)
+static void do_git_path(const struct worktree *wt, struct strbuf *buf,
+			const char *fmt, va_list args)
 {
 	int gitdir_len;
-	strbuf_addstr(buf, get_git_dir());
+	strbuf_addstr(buf, get_worktree_git_dir(wt));
 	if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 		strbuf_addch(buf, '/');
 	gitdir_len = buf->len;
@@ -400,7 +402,7 @@ char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
 	va_list args;
 	strbuf_reset(buf);
 	va_start(args, fmt);
-	do_git_path(buf, fmt, args);
+	do_git_path(NULL, buf, fmt, args);
 	va_end(args);
 	return buf->buf;
 }
@@ -409,7 +411,7 @@ void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 {
 	va_list args;
 	va_start(args, fmt);
-	do_git_path(sb, fmt, args);
+	do_git_path(NULL, sb, fmt, args);
 	va_end(args);
 }
 
@@ -418,7 +420,7 @@ const char *git_path(const char *fmt, ...)
 	struct strbuf *pathname = get_pathname();
 	va_list args;
 	va_start(args, fmt);
-	do_git_path(pathname, fmt, args);
+	do_git_path(NULL, pathname, fmt, args);
 	va_end(args);
 	return pathname->buf;
 }
@@ -428,7 +430,7 @@ char *git_pathdup(const char *fmt, ...)
 	struct strbuf path = STRBUF_INIT;
 	va_list args;
 	va_start(args, fmt);
-	do_git_path(&path, fmt, args);
+	do_git_path(NULL, &path, fmt, args);
 	va_end(args);
 	return strbuf_detach(&path, NULL);
 }
@@ -454,6 +456,16 @@ const char *mkpath(const char *fmt, ...)
 	return cleanup_path(pathname->buf);
 }
 
+const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
+{
+	struct strbuf *pathname = get_pathname();
+	va_list args;
+	va_start(args, fmt);
+	do_git_path(wt, pathname, fmt, args);
+	va_end(args);
+	return pathname->buf;
+}
+
 static void do_submodule_path(struct strbuf *buf, const char *path,
 			      const char *fmt, va_list args)
 {
@@ -503,6 +515,35 @@ void strbuf_git_path_submodule(struct strbuf *buf, const char *path,
 	va_end(args);
 }
 
+static void do_git_common_path(struct strbuf *buf,
+			       const char *fmt,
+			       va_list args)
+{
+	strbuf_addstr(buf, get_git_common_dir());
+	if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
+		strbuf_addch(buf, '/');
+	strbuf_vaddf(buf, fmt, args);
+	strbuf_cleanup_path(buf);
+}
+
+const char *git_common_path(const char *fmt, ...)
+{
+	struct strbuf *pathname = get_pathname();
+	va_list args;
+	va_start(args, fmt);
+	do_git_common_path(pathname, fmt, args);
+	va_end(args);
+	return pathname->buf;
+}
+
+void strbuf_git_common_path(struct strbuf *sb, const char *fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	do_git_common_path(sb, fmt, args);
+	va_end(args);
+}
+
 int validate_headref(const char *path)
 {
 	struct stat st;