1 files changed, 31 insertions, 1 deletions
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index 5bcc7f012..7466c7d41 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -745,7 +745,7 @@ static void rewriteDerivation(Store & store, BasicDerivation & drv, const String
 
 }
 
-std::optional<BasicDerivation> Derivation::tryResolve(Store & store) {
+std::optional<BasicDerivation> Derivation::tryResolveUncached(Store & store) {
     BasicDerivation resolved { *this };
 
     // Input paths that we'll want to rewrite in the derivation
@@ -771,4 +771,34 @@ std::optional<BasicDerivation> Derivation::tryResolve(Store & store) {
     return resolved;
 }
 
+std::optional<BasicDerivation> Derivation::tryResolve(Store& store)
+{
+    auto drvPath = writeDerivation(store, *this, NoRepair, false);
+    return Derivation::tryResolve(store, drvPath);
+}
+
+std::optional<BasicDerivation> Derivation::tryResolve(Store& store, const StorePath& drvPath)
+{
+    // This is quite dirty and leaky, but will disappear once #4340 is merged
+    static Sync<std::map<StorePath, std::optional<Derivation>>> resolutionsCache;
+
+    {
+        auto resolutions = resolutionsCache.lock();
+        auto resolvedDrvIter = resolutions->find(drvPath);
+        if (resolvedDrvIter != resolutions->end()) {
+            auto & [_, resolvedDrv] = *resolvedDrvIter;
+                return *resolvedDrv;
+        }
+    }
+
+    /* Try resolve drv and use that path instead. */
+    auto drv = store.readDerivation(drvPath);
+    auto attempt = drv.tryResolveUncached(store);
+    if (!attempt)
+        return std::nullopt;
+    /* Store in memo table. */
+    resolutionsCache.lock()->insert_or_assign(drvPath, *attempt);
+    return *attempt;
+}
+
 }