Checkdoc would bug out on empty files

* lisp/emacs-lisp/checkdoc.el (checkdoc--next-docstring): Don't
bug out on malformed Emacs Lisp (bug#34760).
(checkdoc-file-comments-engine): Don't bug out on empty buffers.

1 files changed, 8 insertions, 2 deletions

diff --git a/lisp/emacs-lisp/checkdoc.el b/lisp/emacs-lisp/checkdoc.el
index 3e3246352a2..830743f5f89 100644
--- a/lisp/emacs-lisp/checkdoc.el
+++ b/lisp/emacs-lisp/checkdoc.el
@@ -929,7 +929,10 @@ don't move point."
   (pcase (save-excursion (condition-case nil
                              (read (current-buffer))
                            ;; Conservatively skip syntax errors.
-                           (invalid-read-syntax)))
+                           (invalid-read-syntax)
+                           ;; Don't bug out if the file is empty (or a
+                           ;; definition ends prematurely.
+                           (end-of-file)))
     (`(,(or 'defun 'defvar 'defcustom 'defmacro 'defconst 'defsubst 'defadvice)
        ,(pred symbolp)
        ;; Require an initializer, i.e. ignore single-argument `defvar'
@@ -2250,7 +2253,10 @@ Code:, and others referenced in the style guide."
                     (re-search-forward "^(require" nil t)
                     (re-search-forward "^(" nil t))
                 (beginning-of-line))
-               (t (re-search-forward ";;; .* --- .*\n")))
+               ((not (re-search-forward ";;; .* --- .*\n" nil t))
+                (checkdoc-create-error
+                 "You should have a summary line (\";;; .* --- .*\")"
+                 nil nil t)))
               (if (checkdoc-y-or-n-p
                    "You should have a \";;; Commentary:\", add one? ")
                   (insert "\n;;; Commentary:\n;; \n\n")