FlakeIds are now properly looked up in registries

src/libexpr/primops/flakeref.hh

@@ -160,5 +160,23 @@ struct FlakeRef
     bool isImmutable() const;
 
     FlakeRef baseRef() const;
+
+    void setRef(std::optional<std::string> ref) {
+        if (auto refData = std::get_if<IsGit>(&data))
+            refData->ref = ref;
+        else if (auto refData = std::get_if<IsGitHub>(&data))
+            refData->ref = ref;
+        else if (auto refData = std::get_if<IsFlakeId>(&data))
+            refData->ref = ref;
+    }
+
+    void setRev(std::optional<Hash> rev) {
+        if (auto refData = std::get_if<IsGit>(&data))
+            refData->rev = rev;
+        else if (auto refData = std::get_if<IsGitHub>(&data))
+            refData->rev = rev;
+        else if (auto refData = std::get_if<IsFlakeId>(&data))
+            refData->rev = rev;
+    }
 };
 }