Preventing the addition of an extra newline when undoing a Backspace or Delete

at the tail of the file while nonewlines is not set.


git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@5250 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

ChangeLog

@@ -1,3 +1,12 @@
+2015-06-17  Benno Schulenberg  <bensberg@justemail.net>
+	* src/text.c (do_undo, add_undo): When undoing a Backspace at the tail
+	of the file and nonewlines is not set, then don't add another newline
+	but just reposition the cursor.  Also, when doing a Delete at the tail
+	of the file, don't add a superfluous undo structure.  This prevents
+	the appearance of an extra newline when undoing the Backspace/Delete.
+	Patch partially by Mark Majeres.  The problem was first reported in
+	https://lists.gnu.org/archive/html/nano-devel/2015-06/msg00003.html.
+
 2015-06-14  Benno Schulenberg  <bensberg@justemail.net>
 	* src/winio.c (edit_draw): Add some debugging code to track which
 	multidata codes (for multiline regexes) get assigned to which lines.

src/text.c

@@ -501,6 +501,10 @@ void do_undo(void)
 #endif /* !DISABLE_WRAPPING */
     case JOIN:
 	undidmsg = _("line join");
+	/* When the join was done by a Backspace at the tail of the file,
+	 * don't actually add another line; just position the cursor. */
+	if (f->next != openfile->filebot || u->xflags != UNdel_backspace ||
+		ISSET(NO_NEWLINES)) {
 	t = make_new_node(f);
 	t->data = mallocstrcpy(NULL, u->strdata);
 	data = mallocstrncpy(NULL, f->data, u->mark_begin_x + 1);
@@ -510,6 +514,7 @@ void do_undo(void)
 	splice_node(f, t, f->next);
 	if (f == openfile->filebot)
 	    openfile->filebot = t;
+	}
 	goto_line_posx(u->lineno, u->begin);
 	break;
     case CUT_EOF:
@@ -880,6 +885,11 @@ void add_undo(undo_type current_action)
 	((current_action == CUT && u->type == CUT && !u->mark_set && keeping_cutbuffer()) ||
 	(current_action == ADD && u->type == ADD && u->mark_begin_x == fs->current_x)))
 	return;
+    /* When trying to delete the final newline, don't add an undo for it. */
+    if (current_action == DEL && openfile->current->next == openfile->filebot &&
+		openfile->current->data[openfile->current_x] == '\0' &&
+		openfile->current_x != 0 && !ISSET(NO_NEWLINES))
+	return;
 
     /* Blow away the old undo stack if we are starting from the middle. */
     while (fs->undotop != NULL && fs->undotop != fs->current_undo) {
@@ -924,6 +934,7 @@ void add_undo(undo_type current_action)
     case ADD:
 	break;
     case BACK:
+	u->xflags = UNdel_backspace;
     case DEL:
 	if (u->begin != strlen(fs->current->data)) {
 	    char *char_buf = charalloc(mb_cur_max() + 1);