1 files changed, 12 insertions, 0 deletions
diff --git a/src/libstore/downstream-placeholder.hh b/src/libstore/downstream-placeholder.hh
index 97f77e6b8..9372dcd58 100644
--- a/src/libstore/downstream-placeholder.hh
+++ b/src/libstore/downstream-placeholder.hh
@@ -3,6 +3,7 @@
 
 #include "hash.hh"
 #include "path.hh"
+#include "derived-path.hh"
 
 namespace nix {
 
@@ -73,6 +74,17 @@ public:
         const DownstreamPlaceholder & drvPlaceholder,
         std::string_view outputName,
         const ExperimentalFeatureSettings & xpSettings = experimentalFeatureSettings);
+
+    /**
+     * Convenience constructor that handles both cases (unknown
+     * content-addressed output and unknown derivation), delegating as
+     * needed to `unknownCaOutput` and `unknownDerivation`.
+     *
+     * Recursively builds up a placeholder from a
+     * `SingleDerivedPath::Built.drvPath` chain.
+     */
+    static DownstreamPlaceholder fromSingleDerivedPathBuilt(
+        const SingleDerivedPath::Built & built);
 };
 
 }