Asset Catalogs: treat first-loaded catalog as main catalog

When there are multiple catalogs with the same path (so different UUIDs
all mapped to the same catalog path), treat the first-loaded one as the
main catalog for that path, and the rest as aliases.

This ensures that the UUID of a catalog (as chosen in the tree UI and thus
interacted with by users) is stable, regardless of whether by some coincidence
later another catalog with the same UUID is created.

1 files changed, 12 insertions, 3 deletions

diff --git a/source/blender/blenkernel/BKE_asset_catalog.hh b/source/blender/blenkernel/BKE_asset_catalog.hh
index ca4517707e3..5de74efe2cf 100644
--- a/source/blender/blenkernel/BKE_asset_catalog.hh
+++ b/source/blender/blenkernel/BKE_asset_catalog.hh
@@ -108,8 +108,12 @@ class AssetCatalogService {
   /** Return catalog with the given ID. Return nullptr if not found. */
   AssetCatalog *find_catalog(CatalogID catalog_id) const;
 
-  /** Return first catalog with the given path. Return nullptr if not found. This is not an
-   * efficient call as it's just a linear search over the catalogs. */
+  /**
+   * Return first catalog with the given path. Return nullptr if not found. This is not an
+   * efficient call as it's just a linear search over the catalogs.
+   *
+   * If there are multiple catalogs with the same path, return the first-loaded one. If there is
+   * none marked as "first loaded", return the one with the lowest UUID. */
   AssetCatalog *find_catalog_by_path(const AssetCatalogPath &path) const;
 
   /**
@@ -416,7 +420,7 @@ class AssetCatalog {
   static std::string sensible_simple_name_for_path(const AssetCatalogPath &path);
 };
 
-/** Comparator for asset catalogs, ordering by (path, UUID). */
+/** Comparator for asset catalogs, ordering by (path, first_seen, UUID). */
 struct AssetCatalogLessThan {
   bool operator()(const AssetCatalog *lhs, const AssetCatalog *rhs) const
   {
@@ -424,6 +428,10 @@ struct AssetCatalogLessThan {
       return lhs->path < rhs->path;
     }
 
+    if (lhs->flags.is_first_loaded != rhs->flags.is_first_loaded) {
+      return lhs->flags.is_first_loaded;
+    }
+
     return lhs->catalog_id < rhs->catalog_id;
   }
 };
@@ -432,6 +440,7 @@ struct AssetCatalogLessThan {
  * Set that stores catalogs ordered by (path, UUID).
  * Being a set, duplicates are removed. The catalog's simple name is ignored in this. */
 using AssetCatalogOrderedSet = std::set<const AssetCatalog *, AssetCatalogLessThan>;
+using MutableAssetCatalogOrderedSet = std::set<AssetCatalog *, AssetCatalogLessThan>;
 
 /**
  * Filter that can determine whether an asset should be visible or not, based on its catalog ID.