Merge branch 'es/worktree-add-cleanup'

The "new-worktree-mode" hack in "checkout" that was added in
nd/multiple-work-trees topic has been removed by updating the
implementation of new "worktree add".

* es/worktree-add-cleanup: (25 commits)
  Documentation/git-worktree: fix duplicated 'from'
  Documentation/config: mention "now" and "never" for 'expire' settings
  Documentation/git-worktree: fix broken 'linkgit' invocation
  checkout: drop intimate knowledge of newly created worktree
  worktree: populate via "git reset --hard" rather than "git checkout"
  worktree: avoid resolving HEAD unnecessarily
  worktree: make setup of new HEAD distinct from worktree population
  worktree: detect branch-name/detached and error conditions locally
  worktree: add_worktree: construct worktree-population command locally
  worktree: elucidate environment variables intended for child processes
  worktree: make branch creation distinct from worktree population
  worktree: add: suppress auto-vivication with --detach and no <branch>
  worktree: make --detach mutually exclusive with -b/-B
  worktree: introduce options container
  worktree: simplify new branch (-b/-B) option checking
  worktree: improve worktree setup message
  branch: publish die_if_checked_out()
  checkout: teach check_linked_checkout() about symbolic link HEAD
  checkout: check_linked_checkout: simplify symref parsing
  checkout: check_linked_checkout: improve "already checked out" aesthetic
  ...

1 files changed, 67 insertions, 0 deletions

diff --git a/branch.c b/branch.c
index b0024353f4..c85be0785b 100644
--- a/branch.c
+++ b/branch.c
@@ -310,3 +310,70 @@ void remove_branch_state(void)
 	unlink(git_path("MERGE_MODE"));
 	unlink(git_path("SQUASH_MSG"));
 }
+
+static void check_linked_checkout(const char *branch, const char *id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	struct strbuf path = STRBUF_INIT;
+	struct strbuf gitdir = STRBUF_INIT;
+
+	/*
+	 * $GIT_COMMON_DIR/HEAD is practically outside
+	 * $GIT_DIR so resolve_ref_unsafe() won't work (it
+	 * uses git_path). Parse the ref ourselves.
+	 */
+	if (id)
+		strbuf_addf(&path, "%s/worktrees/%s/HEAD", get_git_common_dir(), id);
+	else
+		strbuf_addf(&path, "%s/HEAD", get_git_common_dir());
+
+	if (!strbuf_readlink(&sb, path.buf, 0)) {
+		if (!starts_with(sb.buf, "refs/") ||
+		    check_refname_format(sb.buf, 0))
+			goto done;
+	} else if (strbuf_read_file(&sb, path.buf, 0) >= 0 &&
+	    starts_with(sb.buf, "ref:")) {
+		strbuf_remove(&sb, 0, strlen("ref:"));
+		strbuf_trim(&sb);
+	} else
+		goto done;
+	if (strcmp(sb.buf, branch))
+		goto done;
+	if (id) {
+		strbuf_reset(&path);
+		strbuf_addf(&path, "%s/worktrees/%s/gitdir", get_git_common_dir(), id);
+		if (strbuf_read_file(&gitdir, path.buf, 0) <= 0)
+			goto done;
+		strbuf_rtrim(&gitdir);
+	} else
+		strbuf_addstr(&gitdir, get_git_common_dir());
+	skip_prefix(branch, "refs/heads/", &branch);
+	strbuf_strip_suffix(&gitdir, ".git");
+	die(_("'%s' is already checked out at '%s'"), branch, gitdir.buf);
+done:
+	strbuf_release(&path);
+	strbuf_release(&sb);
+	strbuf_release(&gitdir);
+}
+
+void die_if_checked_out(const char *branch)
+{
+	struct strbuf path = STRBUF_INIT;
+	DIR *dir;
+	struct dirent *d;
+
+	check_linked_checkout(branch, NULL);
+
+	strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
+	dir = opendir(path.buf);
+	strbuf_release(&path);
+	if (!dir)
+		return;
+
+	while ((d = readdir(dir)) != NULL) {
+		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+			continue;
+		check_linked_checkout(branch, d->d_name);
+	}
+	closedir(dir);
+}