Object: improve on fix for Object.to_mesh() crash T86871

While fa7ddd0f43 fixed the reported issue,
the possibility of reusing runtime data during curve-to-mesh conversion
remained. Instead of treating the bounding-box as a special case,
clear all run-time data for temporary objects.

Ref D11026

Reviewed By: sergey

source/blender/blenkernel/BKE_object.h

@@ -374,6 +374,7 @@ struct MovieClip *BKE_object_movieclip_get(struct Scene *scene,
 
 void BKE_object_runtime_reset(struct Object *object);
 void BKE_object_runtime_reset_on_copy(struct Object *object, const int flag);
+void BKE_object_runtime_free(struct Object *object);
 
 void BKE_object_batch_cache_dirty_tag(struct Object *ob);
 

source/blender/blenkernel/intern/mesh_convert.c

@@ -1027,11 +1027,15 @@ static Object *object_for_curve_to_mesh_create(Object *object)
    *
    * Note that there are extra fields in there like bevel and path, but those are not needed during
    * conversion, so they are not copied to save unnecessary allocations. */
-  if (object->runtime.curve_cache != NULL) {
+  if (temp_object->runtime.curve_cache == NULL) {
     temp_object->runtime.curve_cache = MEM_callocN(sizeof(CurveCache),
                                                    "CurveCache for curve types");
+  }
+
+  if (object->runtime.curve_cache != NULL) {
     BKE_displist_copy(&temp_object->runtime.curve_cache->disp, &object->runtime.curve_cache->disp);
   }
+
   /* Constructive modifiers will use mesh to store result. */
   if (object->runtime.data_eval != NULL) {
     BKE_id_copy_ex(
@@ -1059,15 +1063,17 @@ static Object *object_for_curve_to_mesh_create(Object *object)
 
 static void curve_to_mesh_eval_ensure(Object *object)
 {
-  if (object->runtime.curve_cache == NULL) {
-    object->runtime.curve_cache = MEM_callocN(sizeof(CurveCache), "CurveCache for Curve");
-  }
   Curve *curve = (Curve *)object->data;
   Curve remapped_curve = *curve;
   Object remapped_object = *object;
-  remapped_object.runtime.bb = NULL;
+  BKE_object_runtime_reset(&remapped_object);
+
   remapped_object.data = &remapped_curve;
 
+  if (remapped_object.runtime.curve_cache == NULL) {
+    remapped_object.runtime.curve_cache = MEM_callocN(sizeof(CurveCache), "CurveCache for Curve");
+  }
+
   /* Clear all modifiers for the bevel object.
    *
    * This is because they can not be reliably evaluated for an original object (at least because
@@ -1078,8 +1084,8 @@ static void curve_to_mesh_eval_ensure(Object *object)
   Object bevel_object = {{NULL}};
   if (remapped_curve.bevobj != NULL) {
     bevel_object = *remapped_curve.bevobj;
-    bevel_object.runtime.bb = NULL;
     BLI_listbase_clear(&bevel_object.modifiers);
+    BKE_object_runtime_reset(&bevel_object);
     remapped_curve.bevobj = &bevel_object;
   }
 
@@ -1087,8 +1093,8 @@ static void curve_to_mesh_eval_ensure(Object *object)
   Object taper_object = {{NULL}};
   if (remapped_curve.taperobj != NULL) {
     taper_object = *remapped_curve.taperobj;
-    taper_object.runtime.bb = NULL;
     BLI_listbase_clear(&taper_object.modifiers);
+    BKE_object_runtime_reset(&taper_object);
     remapped_curve.taperobj = &taper_object;
   }
 
@@ -1110,12 +1116,9 @@ static void curve_to_mesh_eval_ensure(Object *object)
     BKE_object_eval_assign_data(&remapped_object, &mesh_eval->id, true);
   }
 
-  MEM_SAFE_FREE(remapped_object.runtime.bb);
-  MEM_SAFE_FREE(taper_object.runtime.bb);
-  MEM_SAFE_FREE(bevel_object.runtime.bb);
-
-  BKE_object_free_curve_cache(&bevel_object);
-  BKE_object_free_curve_cache(&taper_object);
+  BKE_object_runtime_free(&remapped_object);
+  BKE_object_runtime_free(&taper_object);
+  BKE_object_runtime_free(&taper_object);
 }
 
 static Mesh *mesh_new_from_curve_type_object(Object *object)

source/blender/blenkernel/intern/object.c

@@ -5113,6 +5113,17 @@ void BKE_object_runtime_reset_on_copy(Object *object, const int UNUSED(flag))
   runtime->geometry_set_eval = NULL;
 }
 
+/**
+ * The function frees memory used by the runtime data, but not the runtime field itself.
+ *
+ * The caller is expected to run #BKE_object_runtime_reset if the struct will be used again.
+ */
+void BKE_object_runtime_free(Object *object)
+{
+  /* Currently this is all that's needed. */
+  BKE_object_free_derived_caches(object);
+}
+
 /**
  * Find an associated armature object.
  */