[gegl] Revert "eval_visitor: Set output to NULL for 0x0 rects"

[Daniel Sabo <daniels src gnome org>]

commit 623158d03388909a876797d629d359969e0e75f2
Author: Daniel Sabo <DanielSabo gmail com>
Date:   Tue May 21 11:46:02 2013 -0700

    Revert "eval_visitor: Set output to NULL for 0x0 rects"
    
    This reverts commit c8512d2be3defff8eefbed953d3980984f665069.

 gegl/process/gegl-eval-visitor.c |   60 ++++++++++++++++++++-----------------
 1 files changed, 32 insertions(+), 28 deletions(-)
---
diff --git a/gegl/process/gegl-eval-visitor.c b/gegl/process/gegl-eval-visitor.c
index 83e31fd..92920ae 100644
--- a/gegl/process/gegl-eval-visitor.c
+++ b/gegl/process/gegl-eval-visitor.c
@@ -84,7 +84,7 @@ gegl_eval_visitor_visit_pad (GeglVisitor *self,
           if ((context->result_rect.width == 0 || context->result_rect.height == 0))
             {
               /* 0px processing, bail */
-              gegl_operation_context_take_object (context, "output", NULL);
+              gegl_operation_context_take_object (context, "output", G_OBJECT (gegl_buffer_new (NULL, 
NULL)));
             }
           else
             {
@@ -138,36 +138,40 @@ gegl_eval_visitor_visit_pad (GeglVisitor *self,
                                           gegl_pad_get_name (source_pad),
                                           &value);
 
-          if (g_value_get_object (&value))
+          if (!g_value_get_object (&value) &&
+              !g_object_get_data (G_OBJECT (source_node), "graph"))
+            g_warning ("eval-visitor encountered a NULL buffer passed from: %s.%s-[%p]",
+                       gegl_node_get_debug_name (source_node),
+                       gegl_pad_get_name (source_pad),
+                       g_value_get_object (&value));
+
+          gegl_operation_context_set_property (context,
+                                          gegl_pad_get_name (pad),
+                                          &value);
+          /* reference counting for this source dropped to zero, freeing up */
+          if (-- gegl_node_get_context (
+                     gegl_pad_get_node (source_pad), context_id)->refs == 0 &&
+              g_value_get_object (&value))
             {
-              gegl_operation_context_set_property (context,
-                                                   gegl_pad_get_name (pad),
-                                                   &value);
-              /* reference counting for this source dropped to zero, freeing up */
-              if (-- gegl_node_get_context (
-                         gegl_pad_get_node (source_pad), context_id)->refs == 0 &&
-                  g_value_get_object (&value))
-                {
-                  gegl_operation_context_remove_property (
-                     gegl_node_get_context (
-                        gegl_pad_get_node (source_pad), context_id),
-                        gegl_pad_get_name (source_pad));
-                }
+              gegl_operation_context_remove_property (
+                 gegl_node_get_context (
+                    gegl_pad_get_node (source_pad), context_id),
+                    gegl_pad_get_name (source_pad));
+            }
 
-              g_value_unset (&value);
+          g_value_unset (&value);
 
-              /* processing for sink operations that accepts partial consumption
-               * and thus probably are being processed by the processor from the
-               * this very operation.
-               */
-              if (GEGL_IS_OPERATION_SINK (operation) &&
-                  !gegl_operation_sink_needs_full (operation) &&
-                  context->result_rect.width > 0 && context->result_rect.height > 0)
-                {
-                  GEGL_NOTE (GEGL_DEBUG_PROCESS, "Processing pad '%s' on \"%s\"", gegl_pad_get_name (pad), 
gegl_node_get_debug_name (node));
-                  gegl_operation_process (operation, context, "output",
-                    &context->result_rect, context->level);
-                }
+         /* processing for sink operations that accepts partial consumption
+             and thus probably are being processed by the processor from the
+             this very operation.
+           */
+          if (GEGL_IS_OPERATION_SINK (operation) &&
+              !gegl_operation_sink_needs_full (operation) &&
+              context->result_rect.width > 0 && context->result_rect.height > 0)
+            {
+              GEGL_NOTE (GEGL_DEBUG_PROCESS, "Processing pad '%s' on \"%s\"", gegl_pad_get_name (pad), 
gegl_node_get_debug_name (node));
+              gegl_operation_process (operation, context, "output",
+                &context->result_rect, context->level);
             }
         }
     }