[gnome-builder] highlight-engine: be resilient against GtkSourceBuffer

[Christian Hergert <chergert src gnome org>]

commit 0ef0202de3c6968398cc2bf163b3c58f49e2234d
Author: Christian Hergert <christian hergert me>
Date:   Thu May 21 01:20:14 2015 -0700

    highlight-engine: be resilient against GtkSourceBuffer

 libide/ide-highlight-engine.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/libide/ide-highlight-engine.c b/libide/ide-highlight-engine.c
index 6230f5a..ccd6a03 100644
--- a/libide/ide-highlight-engine.c
+++ b/libide/ide-highlight-engine.c
@@ -668,10 +668,13 @@ static void
 ide_highlight_engine_set_buffer (IdeHighlightEngine *self,
                                  IdeBuffer          *buffer)
 {
-  g_return_if_fail (IDE_IS_HIGHLIGHT_ENGINE (self));
-  g_return_if_fail (IDE_IS_BUFFER (buffer));
+  g_assert (IDE_IS_HIGHLIGHT_ENGINE (self));
+  g_assert (!buffer || GTK_IS_TEXT_BUFFER (buffer));
 
-  if (self->buffer != buffer)
+  /*
+   * We can get GtkSourceBuffer intermittently here.
+   */
+  if (!buffer || IDE_IS_BUFFER (buffer))
     {
       egg_signal_group_set_target (self->signal_group, buffer);
       g_object_notify_by_pspec (G_OBJECT (self), gParamSpecs [PROP_BUFFER]);