Fix potential issues when loading files with missing libraries

This is a continuation of rB39f005eae8eed8b939579aff8c9a05a4f50e5e38

Now all the fields where we check for object type in RNA (like
rna_Curve_object_poll) will have a safe guard for when this isn't the
case.  For example when loading files that has missing object libraries
and all missing objects are replaced with empties (placeholders).

Reviewed By: Brecht

Differential Revision: http://developer.blender.org/D5425

1 files changed, 13 insertions, 1 deletions

diff --git a/source/blender/modifiers/intern/MOD_shrinkwrap.c b/source/blender/modifiers/intern/MOD_shrinkwrap.c
index 07182d82fdc..408ec06a49c 100644
--- a/source/blender/modifiers/intern/MOD_shrinkwrap.c
+++ b/source/blender/modifiers/intern/MOD_shrinkwrap.c
@@ -75,7 +75,19 @@ static bool isDisabled(const struct Scene *UNUSED(scene),
                        bool UNUSED(useRenderParams))
 {
   ShrinkwrapModifierData *smd = (ShrinkwrapModifierData *)md;
-  return !smd->target;
+
+  /* The object type check is only needed here in case we have a placeholder
+   * object assigned (because the library containing the mesh is missing).
+   *
+   * In other cases it should be impossible to have a type missmatch.
+   */
+  if (!smd->target || smd->target->type != OB_MESH) {
+    return true;
+  }
+  else if (smd->auxTarget && smd->auxTarget->type != OB_MESH) {
+    return true;
+  }
+  return false;
 }
 
 static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)