IDType owner ID accessor: Add option to skip relationship sanity checks.

While currently, all cases where `BKE_id_owner_get` is called are
'safe', there are some points in code where the pointers ensureing the
relationship between an embedded ID and its owner are not (fully) valid.

This new option (`false` by default) allows to skip the debug asserts
ensuring the sanity of these 'owner <-> embedded' ID pointers in the
relevant `owner_pointer_get` callbacks.

This change is not expected to have any effect in current codebase.

source/blender/blenkernel/BKE_idtype.hh

@@ -89,7 +89,15 @@ using IDTypeForeachCacheFunction = void (*)(ID *id,
 
 using IDTypeForeachPathFunction = void (*)(ID *id, BPathForeachPathData *bpath_data);
 
-using IDTypeEmbeddedOwnerPointerGetFunction = ID **(*)(ID *id);
+/**
+ * Callback returning the address of the pointer to the owner ID, for embedded (and Shapekey) ones.
+ *
+ * \param debug_relationship_assert: usually the owner <-> embedded relation pointers should be
+ * fully valid, and can be asserted on. But in some cases, they are not (fully) valid, e.g when
+ * copying an ID and all of its embedded data.
+ */
+using IDTypeEmbeddedOwnerPointerGetFunction = ID *
+                                              *(*)(ID * id, const bool debug_relationship_assert);
 
 using IDTypeBlendWriteFunction = void (*)(BlendWriter *writer, ID *id, const void *id_address);
 using IDTypeBlendReadDataFunction = void (*)(BlendDataReader *reader, ID *id);

source/blender/blenkernel/BKE_lib_id.hh

@@ -711,8 +711,12 @@ bool BKE_id_can_be_asset(const ID *id);
  * Return the owner ID of the given `id`, if any.
  *
  * \note This will only return non-NULL for embedded IDs (master collections etc.), and shape-keys.
+ *
+ * \param debug_relationship_assert: True by default, whether to perform debug checks on validity
+ * of the pointers between owner and embedded IDs. In some cases, these relations are not yet
+ * (fully) valid, e.g. during ID copying.
  */
-ID *BKE_id_owner_get(ID *id);
+ID *BKE_id_owner_get(ID *id, const bool debug_relationship_assert = true);
 
 /**
  * Check if that ID can be considered as editable from a high-level (editor) perspective.

source/blender/blenkernel/intern/collection.cc

@@ -249,7 +249,7 @@ static void collection_foreach_id(ID *id, LibraryForeachIDData *data)
   }
 }
 
-static ID **collection_owner_pointer_get(ID *id)
+static ID **collection_owner_pointer_get(ID *id, const bool debug_relationship_assert)
 {
   if ((id->flag & LIB_EMBEDDED_DATA) == 0) {
     return nullptr;
@@ -257,9 +257,11 @@ static ID **collection_owner_pointer_get(ID *id)
 
   Collection *master_collection = (Collection *)id;
   BLI_assert((master_collection->flag & COLLECTION_IS_MASTER) != 0);
+  if (debug_relationship_assert) {
     BLI_assert(master_collection->owner_id != nullptr);
     BLI_assert(GS(master_collection->owner_id->name) == ID_SCE);
     BLI_assert(((Scene *)master_collection->owner_id)->master_collection == master_collection);
+  }
 
   return &master_collection->owner_id;
 }

source/blender/blenkernel/intern/key.cc

@@ -103,12 +103,14 @@ static void shapekey_foreach_id(ID *id, LibraryForeachIDData *data)
   }
 }
 
-static ID **shapekey_owner_pointer_get(ID *id)
+static ID **shapekey_owner_pointer_get(ID *id, const bool debug_relationship_assert)
 {
   Key *key = (Key *)id;
 
+  if (debug_relationship_assert) {
     BLI_assert(key->from != nullptr);
     BLI_assert(BKE_key_from_id(key->from) == key);
+  }
 
   return &key->from;
 }

source/blender/blenkernel/intern/lib_id.cc

@@ -2209,11 +2209,11 @@ bool BKE_id_can_be_asset(const ID *id)
          BKE_idtype_idcode_is_linkable(GS(id->name));
 }
 
-ID *BKE_id_owner_get(ID *id)
+ID *BKE_id_owner_get(ID *id, const bool debug_relationship_assert)
 {
   const IDTypeInfo *idtype = BKE_idtype_get_info_from_id(id);
   if (idtype->owner_pointer_get != nullptr) {
-    ID **owner_id_pointer = idtype->owner_pointer_get(id);
+    ID **owner_id_pointer = idtype->owner_pointer_get(id, debug_relationship_assert);
     if (owner_id_pointer != nullptr) {
       return *owner_id_pointer;
     }

source/blender/blenkernel/intern/node.cc

@@ -456,7 +456,7 @@ static void node_foreach_path(ID *id, BPathForeachPathData *bpath_data)
   }
 }
 
-static ID **node_owner_pointer_get(ID *id)
+static ID **node_owner_pointer_get(ID *id, const bool debug_relationship_assert)
 {
   if ((id->flag & LIB_EMBEDDED_DATA) == 0) {
     return nullptr;
@@ -465,8 +465,10 @@ static ID **node_owner_pointer_get(ID *id)
   // BLI_assert((id->tag & LIB_TAG_NO_MAIN) == 0);
 
   bNodeTree *ntree = reinterpret_cast<bNodeTree *>(id);
+  if (debug_relationship_assert) {
     BLI_assert(ntree->owner_id != nullptr);
     BLI_assert(ntreeFromID(ntree->owner_id) == ntree);
+  }
 
   return &ntree->owner_id;
 }