[Emacs-diffs] master 1f02cbe: Fix bug#21766 and add test

[Juanma Barranquero]

branch: master
commit 1f02cbea8b489ed7676110431aa36ad5abc47d9b
Author: Juanma Barranquero <address@hidden>
Commit: Juanma Barranquero <address@hidden>

    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.
---
 lisp/simple.el                |    3 ++-
 test/automated/simple-test.el |   22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletions(-)

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 @@ buffer if the variable `delete-trailing-lines' is non-nil."
             (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 @@
           (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