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

source/blender/editors/object/object_constraint.c

@@ -493,8 +493,12 @@ static void test_constraint(
                CONSTRAINT_TYPE_CLAMPTO,
                CONSTRAINT_TYPE_SPLINEIK)) {
         if (ct->tar) {
+          /* The object type check is only needed here in case we have a placeholder
+           * object assigned (because the library containing the curve is missing).
+           *
+           * In other cases it should be impossible to have a type missmatch.
+           */
           if (ct->tar->type != OB_CURVE) {
-            ct->tar = NULL;
             con->flag |= CONSTRAINT_DISABLE;
           }
           else {
@@ -507,8 +511,12 @@ static void test_constraint(
       }
       else if (con->type == CONSTRAINT_TYPE_ARMATURE) {
         if (ct->tar) {
+          /* 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.
+           */
           if (ct->tar->type != OB_ARMATURE) {
-            ct->tar = NULL;
             con->flag |= CONSTRAINT_DISABLE;
           }
           else if (!BKE_armature_find_bone_name(BKE_armature_from_object(ct->tar),

source/blender/gpencil_modifiers/intern/MOD_gpencilarmature.c

@@ -155,7 +155,12 @@ static bool isDisabled(GpencilModifierData *md, int UNUSED(userRenderParams))
 {
   ArmatureGpencilModifierData *mmd = (ArmatureGpencilModifierData *)md;
 
-  return !mmd->object;
+  /* 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->object || mmd->object->type != OB_ARMATURE;
 }
 
 static void updateDepsgraph(GpencilModifierData *md, const ModifierUpdateDepsgraphContext *ctx)

source/blender/gpencil_modifiers/intern/MOD_gpencillattice.c

@@ -169,7 +169,12 @@ static bool isDisabled(GpencilModifierData *md, int UNUSED(userRenderParams))
 {
   LatticeGpencilModifierData *mmd = (LatticeGpencilModifierData *)md;
 
-  return !mmd->object;
+  /* The object type check is only needed here in case we have a placeholder
+   * object assigned (because the library containing the lattice is missing).
+   *
+   * In other cases it should be impossible to have a type missmatch.
+   */
+  return !mmd->object || mmd->object->type != OB_LATTICE;
 }
 
 static void updateDepsgraph(GpencilModifierData *md, const ModifierUpdateDepsgraphContext *ctx)

source/blender/modifiers/intern/MOD_armature.c

@@ -82,7 +82,7 @@ static bool isDisabled(const struct Scene *UNUSED(scene),
   /* 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.
+   * In other cases it should be impossible to have a type missmatch.
    */
   return !amd->object || amd->object->type != OB_ARMATURE;
 }

source/blender/modifiers/intern/MOD_array.c

@@ -395,7 +395,7 @@ static Mesh *arrayModifier_doArray(ArrayModifierData *amd,
   count = amd->count;
 
   Object *start_cap_ob = amd->start_cap;
-  if (start_cap_ob && start_cap_ob != ctx->object && start_cap_ob->type == OB_MESH) {
+  if (start_cap_ob && start_cap_ob != ctx->object) {
     vgroup_start_cap_remap = BKE_object_defgroup_index_map_create(
         start_cap_ob, ctx->object, &vgroup_start_cap_remap_len);
 
@@ -408,7 +408,7 @@ static Mesh *arrayModifier_doArray(ArrayModifierData *amd,
     }
   }
   Object *end_cap_ob = amd->end_cap;
-  if (end_cap_ob && end_cap_ob != ctx->object && end_cap_ob->type == OB_MESH) {
+  if (end_cap_ob && end_cap_ob != ctx->object) {
     vgroup_end_cap_remap = BKE_object_defgroup_index_map_create(
         end_cap_ob, ctx->object, &vgroup_end_cap_remap_len);
 
@@ -465,13 +465,10 @@ static Mesh *arrayModifier_doArray(ArrayModifierData *amd,
 
   if (amd->fit_type == MOD_ARR_FITCURVE && amd->curve_ob != NULL) {
     Object *curve_ob = amd->curve_ob;
-    Curve *cu = curve_ob->data;
-    if (cu) {
-      CurveCache *curve_cache = curve_ob->runtime.curve_cache;
-      if (curve_cache != NULL && curve_cache->path != NULL) {
-        float scale_fac = mat4_to_scale(curve_ob->obmat);
-        length = scale_fac * curve_cache->path->totdist;
-      }
+    CurveCache *curve_cache = curve_ob->runtime.curve_cache;
+    if (curve_cache != NULL && curve_cache->path != NULL) {
+      float scale_fac = mat4_to_scale(curve_ob->obmat);
+      length = scale_fac * curve_cache->path->totdist;
     }
   }
 
@@ -769,6 +766,31 @@ static Mesh *applyModifier(ModifierData *md, const ModifierEvalContext *ctx, Mes
   return arrayModifier_doArray(amd, ctx, mesh);
 }
 
+static bool isDisabled(const struct Scene *UNUSED(scene),
+                       ModifierData *md,
+                       bool UNUSED(useRenderParams))
+{
+  ArrayModifierData *amd = (ArrayModifierData *)md;
+
+  /* The object type check is only needed here in case we have a placeholder
+   * object assigned (because the library containing the curve/mesh is missing).
+   *
+   * In other cases it should be impossible to have a type missmatch.
+   */
+
+  if (amd->curve_ob && amd->curve_ob->type != OB_CURVE) {
+    return true;
+  }
+  else if (amd->start_cap && amd->start_cap->type != OB_MESH) {
+    return true;
+  }
+  else if (amd->end_cap && amd->end_cap->type != OB_MESH) {
+    return true;
+  }
+
+  return false;
+}
+
 ModifierTypeInfo modifierType_Array = {
     /* name */ "Array",
     /* structName */ "ArrayModifierData",
@@ -789,7 +811,7 @@ ModifierTypeInfo modifierType_Array = {
     /* initData */ initData,
     /* requiredDataMask */ NULL,
     /* freeData */ NULL,
-    /* isDisabled */ NULL,
+    /* isDisabled */ isDisabled,
     /* updateDepsgraph */ updateDepsgraph,
     /* dependsOnTime */ NULL,
     /* dependsOnNormals */ NULL,

source/blender/modifiers/intern/MOD_boolean.c

@@ -71,7 +71,12 @@ static bool isDisabled(const struct Scene *UNUSED(scene),
 {
   BooleanModifierData *bmd = (BooleanModifierData *)md;
 
-  return !bmd->object;
+  /* 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.
+   */
+  return !bmd->object || bmd->object->type != OB_MESH;
 }
 
 static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)

source/blender/modifiers/intern/MOD_curve.c

@@ -66,7 +66,12 @@ static bool isDisabled(const Scene *UNUSED(scene), ModifierData *md, bool UNUSED
 {
   CurveModifierData *cmd = (CurveModifierData *)md;
 
-  return !cmd->object;
+  /* The object type check is only needed here in case we have a placeholder
+   * object assigned (because the library containing the curve is missing).
+   *
+   * In other cases it should be impossible to have a type missmatch.
+   */
+  return !cmd->object || cmd->object->type != OB_CURVE;
 }
 
 static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)

source/blender/modifiers/intern/MOD_datatransfer.c

@@ -141,9 +141,14 @@ static bool isDisabled(const struct Scene *UNUSED(scene),
                        ModifierData *md,
                        bool UNUSED(useRenderParams))
 {
-  DataTransferModifierData *dtmd = (DataTransferModifierData *)md;
   /* If no source object, bypass. */
-  return (dtmd->ob_source == NULL);
+  DataTransferModifierData *dtmd = (DataTransferModifierData *)md;
+  /* 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.
+   */
+  return !dtmd->ob_source || dtmd->ob_source->type != OB_MESH;
 }
 
 #define HIGH_POLY_WARNING 10000

source/blender/modifiers/intern/MOD_lattice.c

@@ -64,7 +64,12 @@ static bool isDisabled(const struct Scene *UNUSED(scene),
 {
   LatticeModifierData *lmd = (LatticeModifierData *)md;
 
-  return !lmd->object;
+  /* The object type check is only needed here in case we have a placeholder
+   * object assigned (because the library containing the lattice is missing).
+   *
+   * In other cases it should be impossible to have a type missmatch.
+   */
+  return !lmd->object || lmd->object->type != OB_LATTICE;
 }
 
 static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)

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,

source/blender/modifiers/intern/MOD_meshdeform.c

@@ -139,7 +139,12 @@ static bool isDisabled(const struct Scene *UNUSED(scene),
 {
   MeshDeformModifierData *mmd = (MeshDeformModifierData *)md;
 
-  return !mmd->object;
+  /* 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.
+   */
+  return !mmd->object || mmd->object->type != OB_MESH;
 }
 
 static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)

source/blender/modifiers/intern/MOD_particleinstance.c

@@ -80,7 +80,12 @@ static bool isDisabled(const struct Scene *scene, ModifierData *md, bool useRend
   ParticleSystem *psys;
   ModifierData *ob_md;
 
-  if (!pimd->ob) {
+  /* 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 (!pimd->ob || pimd->ob->type != OB_MESH) {
     return true;
   }
 

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)

source/blender/modifiers/intern/MOD_surfacedeform.c

@@ -1279,7 +1279,13 @@ static bool isDisabled(const Scene *UNUSED(scene), ModifierData *md, bool UNUSED
 {
   SurfaceDeformModifierData *smd = (SurfaceDeformModifierData *)md;
 
-  return smd->target == NULL && !(smd->verts != NULL && !(smd->flags & MOD_SDEF_BIND));
+  /* 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.
+   */
+  return (smd->target == NULL || smd->target->type != OB_MESH) &&
+         !(smd->verts != NULL && !(smd->flags & MOD_SDEF_BIND));
 }
 
 ModifierTypeInfo modifierType_SurfaceDeform = {