X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/a985d2b09bb88f31b27b02c3131cb34c5879d767..69b79bdff07bff2174d782dc4c69cf2dadc8225b:/lisp/simple.el

diff --git a/lisp/simple.el b/lisp/simple.el
index a502448b31..6d7f00f52f 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -602,24 +602,23 @@ buffer if the variable `delete-trailing-lines' is non-nil."
                    (list nil nil))))
   (save-match-data
     (save-excursion
-      (let ((end-marker (copy-marker (or end (point-max))))
-            (start (or start (point-min))))
-        (goto-char start)
-        (while (re-search-forward "\\s-$" end-marker t)
-          (skip-syntax-backward "-" (line-beginning-position))
+      (let ((end-marker (and end (copy-marker end))))
+        (goto-char (or start (point-min)))
+        (with-syntax-table (make-syntax-table (syntax-table))
           ;; Don't delete formfeeds, even if they are considered whitespace.
-          (if (looking-at-p ".*\f")
-              (goto-char (match-end 0)))
-          (delete-region (point) (match-end 0)))
-        ;; Delete trailing empty lines.
-        (goto-char end-marker)
-        (when (and (not end)
-		   delete-trailing-lines
-                   ;; Really the end of buffer.
-		   (= (point-max) (1+ (buffer-size)))
-                   (<= (skip-chars-backward "\n") -2))
-          (delete-region (1+ (point)) end-marker))
-        (set-marker end-marker nil))))
+          (modify-syntax-entry ?\f "_")
+          ;; Treating \n as non-whitespace makes things easier.
+          (modify-syntax-entry ?\n "_")
+          (while (re-search-forward "\\s-+$" end-marker t)
+            (delete-region (match-beginning 0) (match-end 0))))
+        (if end
+            (set-marker end-marker nil)
+          ;; Delete trailing empty lines.
+          (and delete-trailing-lines
+               ;; Really the end of buffer.
+               (= (goto-char (point-max)) (1+ (buffer-size)))
+               (<= (skip-chars-backward "\n") -2)
+               (delete-region (1+ (point)) (point-max)))))))
   ;; Return nil for the benefit of `write-file-functions'.
   nil)
 
@@ -2884,6 +2883,10 @@ REASON describes the reason that the boundary is being added; see
   "Check recently changed buffers and add a boundary if necessary.
 REASON describes the reason that the boundary is being added; see
 `undo-last-boundary' for more information."
+  ;; (Bug #23785) All commands should ensure that there is an undo
+  ;; boundary whether they have changed the current buffer or not.
+  (when (eq cause 'command)
+    (add-to-list 'undo-auto--undoably-changed-buffers (current-buffer)))
   (dolist (b undo-auto--undoably-changed-buffers)
           (when (buffer-live-p b)
             (with-current-buffer b
@@ -3232,11 +3235,11 @@ Noninteractive callers can specify coding systems by binding
 
 The optional second argument OUTPUT-BUFFER, if non-nil,
 says to put the output in some other buffer.
-If OUTPUT-BUFFER is a buffer or buffer name, put the output there.
-If OUTPUT-BUFFER is not a buffer and not nil,
-insert output in current buffer.  (This cannot be done asynchronously.)
-In either case, the buffer is first erased, and the output is
-inserted after point (leaving mark after it).
+If OUTPUT-BUFFER is a buffer or buffer name, erase that buffer
+and insert the output there.
+If OUTPUT-BUFFER is not a buffer and not nil, insert the output
+in current buffer after point leaving mark after it.
+This cannot be done asynchronously.
 
 If the command terminates without error, but generates output,
 and you did not specify \"insert it in the current buffer\",
@@ -3501,10 +3504,10 @@ Command Output*' is deleted.
 
 Optional fourth arg OUTPUT-BUFFER specifies where to put the
 command's output.  If the value is a buffer or buffer name,
-put the output there.  If the value is nil, use the buffer
-`*Shell Command Output*'.  Any other value, excluding nil,
-means to insert the output in the current buffer.  In either case,
-the output is inserted after point (leaving mark after it).
+erase that buffer and insert the output there.
+If the value is nil, use the buffer `*Shell Command Output*'.
+Any other non-nil value means to insert the output in the
+current buffer after START.
 
 Optional fifth arg REPLACE, if non-nil, means to insert the
 output in place of text from START to END, putting point and mark
@@ -5219,6 +5222,7 @@ store it in a Lisp variable.  Example:
 (defmacro save-mark-and-excursion (&rest body)
   "Like `save-excursion', but also save and restore the mark state.
 This macro does what `save-excursion' did before Emacs 25.1."
+  (declare (indent 0) (debug t))
   (let ((saved-marker-sym (make-symbol "saved-marker")))
     `(let ((,saved-marker-sym (save-mark-and-excursion--save)))
        (unwind-protect