Revert the changes to lisp-current-defun-name

* lisp/emacs-lisp/lisp-mode.el (lisp-current-defun-name): Revert
back to the old version before bug#49592.  The new approach just
doesn't work well enough -- we don't really have the data to know
that, say, `make-obsolete-variable' is about the second symbol and
not the first.

1 files changed, 18 insertions, 55 deletions

diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el
index c56a9660e7c..c906ee6e31d 100644
--- a/lisp/emacs-lisp/lisp-mode.el
+++ b/lisp/emacs-lisp/lisp-mode.el
@@ -728,67 +728,30 @@ font-lock keywords will not be case sensitive."
            len))))
 
 (defun lisp-current-defun-name ()
-  "Return the name of the defun at point.
-If there is no defun at point, return the first symbol from the
-top-level form.  If there is no top-level form, return nil.
-
-(\"defun\" here means \"form that defines something\", and is
-decided heuristically.)"
+  "Return the name of the defun at point, or nil."
   (save-excursion
-    (let ((location (point))
-          name)
+    (let ((location (point)))
       ;; If we are now precisely at the beginning of a defun, make sure
       ;; beginning-of-defun finds that one rather than the previous one.
-      (unless (eobp)
-        (forward-char 1))
+      (or (eobp) (forward-char 1))
       (beginning-of-defun)
       ;; Make sure we are really inside the defun found, not after it.
-      (when (and (looking-at "(")
-                 (progn
-                   (end-of-defun)
-                   (< location (point)))
-                 (progn
-                   (forward-sexp -1)
-                   (>= location (point))))
-        (when (looking-at "(")
-          (forward-char 1))
-        ;; Read the defining construct name, typically "defun" or
+      (when (and (looking-at "\\s(")
+                 (progn (end-of-defun)
+                        (< location (point)))
+                 (progn (forward-sexp -1)
+                        (>= location (point))))
+        (if (looking-at "\\s(")
+            (forward-char 1))
+        ;; Skip the defining construct name, typically "defun" or
         ;; "defvar".
-        (let ((symbol (ignore-errors (read (current-buffer)))))
-          (when (and symbol (not (symbolp symbol)))
-            (setq symbol nil))
-          ;; If there's an edebug spec, use that to determine what the
-          ;; name is.
-          (when symbol
-            (let ((spec (or (get symbol 'edebug-form-spec)
-                            (and (eq (get symbol 'lisp-indent-function) 'defun)
-                                 (get 'defun 'edebug-form-spec)))))
-              (save-excursion
-                (when (and (eq (car-safe spec) '&define)
-                           (memq 'name spec))
-                  (pop spec)
-                  (while (and spec (not name))
-                    (let ((candidate (ignore-errors (read (current-buffer)))))
-                      (when (eq (pop spec) 'name)
-                        (when (and (consp candidate)
-                                   (symbolp (car (delete 'quote candidate))))
-                          (setq candidate (car (delete 'quote candidate))))
-                        (setq name candidate
-                              spec nil))))))))
-          ;; We didn't have an edebug spec (or couldn't find the
-          ;; name).  If the symbol starts with \"def\", then it's
-          ;; likely that the next symbol is the name.
-          (when (and (not name)
-                     (string-match-p "\\(\\`\\|-\\)def" (symbol-name symbol)))
-            (when-let ((candidate (ignore-errors (read (current-buffer)))))
-              (cond
-               ((symbolp candidate)
-                (setq name candidate))
-               ((and (consp candidate)
-                     (symbolp (car (delete 'quote candidate))))
-                (setq name (car (delete 'quote candidate)))))))
-          (when-let ((result (or name symbol)))
-            (and (symbolp result) (symbol-name result))))))))
+        (forward-sexp 1)
+        ;; The second element is usually a symbol being defined.  If it
+        ;; is not, use the first symbol in it.
+        (skip-chars-forward " \t\n'(")
+        (buffer-substring-no-properties (point)
+                                        (progn (forward-sexp 1)
+                                               (point)))))))
 
 (defvar-keymap lisp-mode-shared-map
   :doc "Keymap for commands shared by all sorts of Lisp modes."