From 619a3959162729d0cb423bfa2febbc9e9420ce69 Mon Sep 17 00:00:00 2001
From: Sean Whitton <spwhitton@spwhitton.name>
Date: Mon, 7 Sep 2026 14:14:01 +0100
Subject: [PATCH] VC-Dir: Fix error on `n' before "./" has appeared

If you typed `n' before "./" had appeared, Emacs signalled a
wrong-type-argument error.  Now it signals a better one.

* lisp/vc/vc-dir.el (vc-dir--before-dotname-p): Return nil if
the "./" entry hasn't appeared yet.
* test/lisp/vc/vc-tests/vc-test-misc.el
(vc-test-vc-dir-next/previous): Simulate the problem case.

* lisp/emacs-lisp/ewoc.el (ewoc-goto-next): Signal a user-error
instead of a plain error.  This makes sense for all the current
call sites.  (This is secondary to the bug fix above: this code
was never reached, previously.)
---
 lisp/emacs-lisp/ewoc.el               | 2 +-
 lisp/vc/vc-dir.el                     | 6 ++++--
 test/lisp/vc/vc-tests/vc-test-misc.el | 7 +++++++
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/lisp/emacs-lisp/ewoc.el b/lisp/emacs-lisp/ewoc.el
index 118b66eb15f..fcb8ca7d42c 100644
--- a/lisp/emacs-lisp/ewoc.el
+++ b/lisp/emacs-lisp/ewoc.el
@@ -505,7 +505,7 @@ Return the node (or nil if we just passed the last node)."
     ;; (unless (ewoc--filter-hf-nodes ewoc node)
     ;;   (setq node (ewoc--node-nth dll -2)))
     (unless node
-      (error "No next"))
+      (user-error "No next"))
     (ewoc-goto-node ewoc node)))
 
 (defun ewoc-goto-node (ewoc node)
diff --git a/lisp/vc/vc-dir.el b/lisp/vc/vc-dir.el
index b6ba3cb02a9..b3d2dbb677a 100644
--- a/lisp/vc/vc-dir.el
+++ b/lisp/vc/vc-dir.el
@@ -730,8 +730,10 @@ information."
 ;; entry, as determined by the following function.  See bug#81248 for
 ;; further details.
 (defun vc-dir--before-dotname-p ()
-  "Return non-nil if point is before the \"./\" entry."
-  (< (point) (ewoc-location (ewoc-nth vc-ewoc 0))))
+  "Return non-nil if point is before the \"./\" entry.
+If that entry hasn't appeared yet, return nil."
+  (and-let* ((zeroth (ewoc-nth vc-ewoc 0)))
+    (< (point) (ewoc-location zeroth))))
 
 (defun vc-dir-next-line (arg)
   "Go to the next line.
diff --git a/test/lisp/vc/vc-tests/vc-test-misc.el b/test/lisp/vc/vc-tests/vc-test-misc.el
index adbe9c1240b..df680aa9e75 100644
--- a/test/lisp/vc/vc-tests/vc-test-misc.el
+++ b/test/lisp/vc/vc-tests/vc-test-misc.el
@@ -298,6 +298,8 @@ See bug#80803 and bug#80967."
                 (should (equal (vc-dir-fileinfo->state data)
                                'edited))))))))))
 
+;; FIXME: This test only passes once.  Then there is some state left
+;; behind such that it doesn't pass if run again.
 (ert-deftest vc-test-vc-dir-next/previous () ; bug#81248
   "Test navigating with `vc-dir-{next,previous}-{line,directory}'."
   (skip-unless (executable-find vc-git-program))
@@ -356,6 +358,11 @@ See bug#80803 and bug#80967."
           (should (and (looking-at "\\./$") (looking-back "^ +" (pos-bol))))
           (vc-dir-previous-directory)
           (should (and (looking-at "\\./$") (looking-back "^ +" (pos-bol))))
+          ;; Simulate the case in which the status lines haven't come
+          ;; back yet.  This used to give a cryptic non-`user-error'.
+          (goto-char (point-min))
+          (ewoc-filter vc-ewoc #'ignore)
+          (should-error (vc-dir-next-line 1) :type 'user-error)
           (kill-buffer vc-dir-buf))))))
 
 (ert-deftest vc-test-vc-dir-mark/unmark-all-dir-entry () ; bug#81249