[gnome-builder] sourceview: dont allow final line off screen

[Christian Hergert <chergert src gnome org>]

commit 349be234bca2e5733a06217c6d5a492f99eece75
Author: Christian Hergert <chergert redhat com>
Date:   Mon Mar 25 18:54:08 2019 -0700

    sourceview: dont allow final line off screen
    
    This ensures that the final line cannot scroll off the screen
    by clamping the max overscroll to height-line_hieght.
    
    Related #643

 src/libide/sourceview/ide-source-view.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/libide/sourceview/ide-source-view.c b/src/libide/sourceview/ide-source-view.c
index fcd0d0e89..bbb6c4b2e 100644
--- a/src/libide/sourceview/ide-source-view.c
+++ b/src/libide/sourceview/ide-source-view.c
@@ -3810,7 +3810,7 @@ ide_source_view_set_overscroll_num_lines (IdeSourceView *self,
   if (new_margin < 0)
     new_margin = height + new_margin;
 
-  new_margin = CLAMP (new_margin, 0, height);
+  new_margin = CLAMP (new_margin, 0, height - priv->cached_char_height);
 
   g_object_set (self, "bottom-margin", new_margin, NULL);
 }