Discarding the entire undo stack, to prevent nano from making mistakes

when trying to undo edits after an indentation change.
This works around Savannah bug #46591.


git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@5474 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

ChangeLog

@@ -4,6 +4,9 @@
 	* src/text.c (do_justify): Discard the entire undo stack, to prevent
 	nano from dying (or making mistakes) when trying to undo edits after
 	a justification.  This works around Savannah bug #45531.
+	* src/text.c (do_indent): Also here discard the entire undo stack, to
+	prevent nano from making mistakes when trying to undo edits after an
+	indentation change.  This works around Savannah bug #46591.
 
 2015-12-02  Benno Schulenberg  <bensberg@justemail.net>
 	* doc/syntax/python.nanorc: Don't colour triple quotes by themselves.

src/text.c

@@ -394,6 +394,11 @@ void do_indent(ssize_t cols)
 	free(line_indent);
 
     if (indent_changed) {
+	/* Throw away the undo stack, to prevent making mistakes when
+	 * the user tries to undo something in the reindented text. */
+	discard_until(NULL);
+	openfile->current_undo = NULL;
+
 	/* Mark the file as modified. */
 	set_modified();