1 files changed, 15 insertions, 0 deletions
diff --git a/src/libstore/realisation.hh b/src/libstore/realisation.hh
index 9070a6ee2..48d0283de 100644
--- a/src/libstore/realisation.hh
+++ b/src/libstore/realisation.hh
@@ -1,5 +1,8 @@
 #pragma once
 
+#include <variant>
+
+#include "hash.hh"
 #include "path.hh"
 #include <nlohmann/json_fwd.hpp>
 #include "comparator.hh"
@@ -7,6 +10,8 @@
 
 namespace nix {
 
+class Store;
+
 struct DrvOutput {
     // The hash modulo of the derivation
     Hash drvHash;
@@ -93,4 +98,14 @@ struct RealisedPath {
     GENERATE_CMP(RealisedPath, me->raw);
 };
 
+class MissingRealisation : public Error
+{
+public:
+    MissingRealisation(DrvOutput & outputId)
+        : Error( "cannot operate on an output of the "
+                "unbuilt derivation '%s'",
+                outputId.to_string())
+    {}
+};
+
 }