1 files changed, 53 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/lib_id.c b/source/blender/blenkernel/intern/lib_id.c
index 3778e308db6..5a394a05d86 100644
--- a/source/blender/blenkernel/intern/lib_id.c
+++ b/source/blender/blenkernel/intern/lib_id.c
@@ -59,6 +59,7 @@
 
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_build.h"
+#include "DEG_depsgraph_query.h"
 
 #include "RNA_access.h"
 
@@ -708,6 +709,58 @@ ID *BKE_id_copy_for_duplicate(Main *bmain,
   return id->newid;
 }
 
+static int foreach_assign_id_to_orig_callback(LibraryIDLinkCallbackData *cb_data)
+{
+  ID **id_p = cb_data->id_pointer;
+
+  if (*id_p) {
+    ID *id = *id_p;
+    *id_p = DEG_get_original_id(id);
+
+    /* If the ID changes increase the user count.
+     *
+     * This means that the reference to evaluated ID has been changed with a reference to the
+     * original ID which implies that the user count of the original ID is increased.
+     *
+     * The evaluated IDs do not maintain their user counter, so do not change it to avoid issues
+     * with the user counter going negative. */
+    if (*id_p != id) {
+      if ((cb_data->cb_flag & IDWALK_CB_USER) != 0) {
+        id_us_plus(*id_p);
+      }
+    }
+  }
+
+  return IDWALK_RET_NOP;
+}
+
+ID *BKE_id_copy_for_use_in_bmain(Main *bmain, const ID *id)
+{
+  ID *newid = BKE_id_copy(bmain, id);
+
+  if (newid == NULL) {
+    return newid;
+  }
+
+  /* Assign ID references directly used by the given ID to their original complementary parts.
+   *
+   * For example, when is called on an evaluated object will assign object->data to its original
+   * pointer, the evaluated object->data will be kept unchanged. */
+  BKE_library_foreach_ID_link(NULL, newid, foreach_assign_id_to_orig_callback, NULL, IDWALK_NOP);
+
+  /* Shape keys reference on evaluated ID is preserved to keep driver paths available, but the key
+   * data is likely to be invalid now due to modifiers, so clear the shape key reference avoiding
+   * any possible shape corruption. */
+  if (DEG_is_evaluated_id(id)) {
+    Key **key_p = BKE_key_from_id_p(newid);
+    if (key_p) {
+      *key_p = NULL;
+    }
+  }
+
+  return newid;
+}
+
 /**
  * Does a mere memory swap over the whole IDs data (including type-specific memory).
  * \note Most internal ID data itself is not swapped (only IDProperties are).