source/blender/blenkernel/BKE_asset.h

@@ -38,6 +38,13 @@ typedef struct AssetTypeInfo {
 struct AssetMetaData *BKE_asset_metadata_create(void);
 void BKE_asset_metadata_free(struct AssetMetaData **asset_data);
 
+/**
+ * Create a copy of the #AssetMetaData so that it can be assigned to another asset.
+ *
+ * The caller becomes the owner of the returned pointer.
+ */
+struct AssetMetaData *BKE_asset_metadata_copy(const struct AssetMetaData *source);
+
 struct AssetTagEnsureResult {
   struct AssetTag *tag;
   /* Set to false if a tag of this name was already present. */

source/blender/blenkernel/intern/asset.cc

@@ -39,6 +39,38 @@ void BKE_asset_metadata_free(AssetMetaData **asset_data)
   *asset_data = nullptr;
 }
 
+AssetMetaData *BKE_asset_metadata_copy(const AssetMetaData *source)
+{
+  AssetMetaData *copy = BKE_asset_metadata_create();
+
+  copy->local_type_info = source->local_type_info;
+
+  if (source->properties) {
+    copy->properties = IDP_CopyProperty(source->properties);
+  }
+
+  BKE_asset_metadata_catalog_id_set(copy, source->catalog_id, source->catalog_simple_name);
+
+  if (source->author) {
+    copy->author = BLI_strdup(source->author);
+  }
+  if (source->description) {
+    copy->description = BLI_strdup(source->description);
+  }
+  if (source->copyright) {
+    copy->copyright = BLI_strdup(source->copyright);
+  }
+  if (source->license) {
+    copy->license = BLI_strdup(source->license);
+  }
+
+  BLI_duplicatelist(&copy->tags, &source->tags);
+  copy->active_tag = source->active_tag;
+  copy->tot_tags = source->tot_tags;
+
+  return copy;
+}
+
 AssetMetaData::~AssetMetaData()
 {
   if (properties) {

source/blender/editors/asset/ED_asset_mark_clear.h

@@ -12,6 +12,7 @@
 extern "C" {
 #endif
 
+struct AssetMetaData;
 struct ID;
 struct Main;
 struct bContext;
@@ -42,6 +43,18 @@ void ED_asset_generate_preview(const struct bContext *C, struct ID *id);
  */
 bool ED_asset_clear_id(struct ID *id);
 
+/**
+ * Copy the asset metadata to the given destination ID.
+ *
+ * The copy is assigned to \a destination, any pre-existing asset metadata is
+ * freed before that. If \a destination was not yet marked as asset, it will be
+ * after this call.
+ *
+ * \return true when the copy succeeded, false otherwise. The only reason for
+ *  failure is when \a destination is of a type that cannot be an asset.
+ */
+bool ED_asset_copy_to_id(const struct AssetMetaData *asset_data, struct ID *destination);
+
 void ED_assets_pre_save(struct Main *bmain);
 
 bool ED_asset_can_mark_single_from_context(const struct bContext *C);

source/blender/editors/asset/intern/asset_mark_clear.cc

@@ -27,6 +27,9 @@
 #include "ED_asset_mark_clear.h"
 #include "ED_asset_type.h"
 
+#include "WM_api.h"
+#include "WM_types.h"
+
 bool ED_asset_mark_id(ID *id)
 {
   if (id->asset_data) {
@@ -96,3 +99,16 @@ bool ED_asset_can_mark_single_from_context(const bContext *C)
   }
   return ED_asset_type_is_supported(id);
 }
+
+bool ED_asset_copy_to_id(const struct AssetMetaData *asset_data, struct ID *destination)
+{
+  if (!BKE_id_can_be_asset(destination)) {
+    return false;
+  }
+
+  if (destination->asset_data) {
+    BKE_asset_metadata_free(&destination->asset_data);
+  }
+  destination->asset_data = BKE_asset_metadata_copy(asset_data);
+  return true;
+}

source/blender/makesrna/intern/rna_ID.c

@@ -725,6 +725,38 @@ static void rna_ID_asset_clear(ID *id)
   }
 }
 
+static void rna_ID_asset_data_set(PointerRNA *ptr, PointerRNA value, struct ReportList *reports)
+{
+  ID *destination = ptr->data;
+
+  /* Avoid marking as asset by assigning. This should be done wiht .asset_mark(). This is just for
+   * clarity of the API, and to accomodate future changes. */
+  if (destination->asset_data == NULL) {
+    BKE_report(reports,
+               RPT_ERROR,
+               "Asset data can only be assigned to assets. Use asset_mark() to mark as an asset");
+    return;
+  }
+
+  const AssetMetaData *asset_data = value.data;
+  if (asset_data == NULL) {
+    /* Avoid clearing the asset data on assets. Un-marking as asset should be done with
+     * .asset_clear(). This is just for clarity of the API, and to accomodate future changes. */
+    BKE_report(reports, RPT_ERROR, "Asset data cannot be None");
+    return;
+  }
+
+  const bool assigned_ok = ED_asset_copy_to_id(asset_data, destination);
+  if (!assigned_ok) {
+    BKE_reportf(
+        reports, RPT_ERROR, "'%s' is of a type that cannot be an asset", destination->name + 2);
+    return;
+  }
+
+  WM_main_add_notifier(NC_ASSET | NA_EDITED, NULL);
+  WM_main_add_notifier(NC_ID | NA_EDITED, NULL);
+}
+
 static ID *rna_ID_override_create(ID *id, Main *bmain, bool remap_local_usages)
 {
   if (!ID_IS_OVERRIDABLE_LIBRARY(id)) {
@@ -2131,7 +2163,8 @@ static void rna_def_ID(BlenderRNA *brna)
   RNA_def_property_override_flag(prop, PROPOVERRIDE_NO_COMPARISON);
 
   prop = RNA_def_property(srna, "asset_data", PROP_POINTER, PROP_NONE);
-  RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+  RNA_def_property_flag(prop, PROP_EDITABLE);
+  RNA_def_property_pointer_funcs(prop, NULL, "rna_ID_asset_data_set", NULL, NULL);
   RNA_def_property_override_flag(prop, PROPOVERRIDE_NO_COMPARISON);
   RNA_def_property_ui_text(prop, "Asset Data", "Additional data for an asset data-block");