Subject: Re: bug#21766: 25.0.50; delete-trailing-whitespace sometimes deletes non-whitespace

From: Juanma Barranquero <[email-masked]>
Date: Wed, 28 Oct 2015 10:08:14 +0100

On Wed, Oct 28, 2015 at 2:51 AM, Stephen Leake <
[email-masked]> wrote:

> I suggest instead to save the file without extra whitespace, and add code
> to the test to insert the extra whitespace.

The file is quite short, so in this case is better to get rid of it and
just insert its contents into the buffer.

Thanks,

     Juanma

        Fix bug#21766 and add test.

        * lisp/simple.el (delete-trailing-whitespace): Save match data when
        calling `skip-syntax-backward'.
        * test/automated/simple-test.el (simple-delete-trailing-whitespace):
        New test.

diff --git a/lisp/simple.el b/lisp/simple.el
index 338a060..f6c580f 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -609,7 +609,8 @@ delete-trailing-whitespace
             (start (or start (point-min))))
         (goto-char start)
         (while (re-search-forward "\\s-$" end-marker t)
-          (skip-syntax-backward "-" (line-beginning-position))
+          (save-match-data
+            (skip-syntax-backward "-" (line-beginning-position)))
           ;; Don't delete formfeeds, even if they are considered
whitespace.
           (if (looking-at-p ".*\f")
               (goto-char (match-end 0)))
diff --git a/test/automated/simple-test.el b/test/automated/simple-test.el
index 8da575d..5bfb746 100644
--- a/test/automated/simple-test.el
+++ b/test/automated/simple-test.el
@@ -180,5 +180,27 @@ simple-test--dummy-buffer
           (should (= x 2)))
       (remove-hook 'post-self-insert-hook inc))))

+
+;;; `delete-trailing-whitespace'
+(ert-deftest simple-delete-trailing-whitespace ()
+  "Test bug#21766: delete-whitespace sometimes deletes non-whitespace."
+  (defvar python-indent-guess-indent-offset)  ; to avoid a warning
+  (let ((python (featurep 'python))
+        (python-indent-guess-indent-offset nil)
+        (delete-trailing-lines t))
+    (unwind-protect
+        (with-temp-buffer
+          (python-mode)
+          (insert (concat "query = \"\"\"WITH filtered AS \n"
+                          "WHERE      \n"
+                          "\"\"\".format(fv_)\n"
+                          "\n"
+                          "\n"))
+          (delete-trailing-whitespace)
+          (should (equal (count-lines (point-min) (point-max)) 3)))
+      ;; Let's clean up if running interactive
+      (unless (or noninteractive python)
+        (unload-feature 'python)))))
+
 (provide 'simple-test)
 ;;; simple-test.el ends here
-- 
2.6.2.windows.1