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, 15 insertions, 1 deletions

diff --git a/source/blender/modifiers/intern/MOD_mask.c b/source/blender/modifiers/intern/MOD_mask.c
index f2f2b13b0df..bc218114432 100644
--- a/source/blender/modifiers/intern/MOD_mask.c
+++ b/source/blender/modifiers/intern/MOD_mask.c
@@ -344,6 +344,20 @@ static Mesh *applyModifier(ModifierData *md, const ModifierEvalContext *ctx, Mes
   return result;
 }
 
+static bool isDisabled(const struct Scene *UNUSED(scene),
+                       ModifierData *md,
+                       bool UNUSED(useRenderParams))
+{
+  MaskModifierData *mmd = (MaskModifierData *)md;
+
+  /* The object type check is only needed here in case we have a placeholder
+   * object assigned (because the library containing the armature is missing).
+   *
+   * In other cases it should be impossible to have a type missmatch.
+   */
+  return mmd->ob_arm && mmd->ob_arm->type != OB_ARMATURE;
+}
+
 ModifierTypeInfo modifierType_Mask = {
     /* name */ "Mask",
     /* structName */ "MaskModifierData",
@@ -363,7 +377,7 @@ ModifierTypeInfo modifierType_Mask = {
     /* initData */ NULL,
     /* requiredDataMask */ requiredDataMask,
     /* freeData */ NULL,
-    /* isDisabled */ NULL,
+    /* isDisabled */ isDisabled,
     /* updateDepsgraph */ updateDepsgraph,
     /* dependsOnTime */ NULL,
     /* dependsOnNormals */ NULL,