9 files changed, 51 insertions, 34 deletions
diff --git a/src/libstore/binary-cache-store.cc b/src/libstore/binary-cache-store.cc
index 149d414d3..05bf0501d 100644
--- a/src/libstore/binary-cache-store.cc
+++ b/src/libstore/binary-cache-store.cc
@@ -502,22 +502,9 @@ void BinaryCacheStore::addSignatures(const StorePath & storePath, const StringSe
     writeNarInfo(narInfo);
 }
 
-std::optional<std::string> BinaryCacheStore::getBuildLog(const StorePath & path)
+std::optional<std::string> BinaryCacheStore::getBuildLogExact(const StorePath & path)
 {
-    auto drvPath = path;
-
-    if (!path.isDerivation()) {
-        try {
-            auto info = queryPathInfo(path);
-            // FIXME: add a "Log" field to .narinfo
-            if (!info->deriver) return std::nullopt;
-            drvPath = *info->deriver;
-        } catch (InvalidPath &) {
-            return std::nullopt;
-        }
-    }
-
-    auto logPath = "log/" + std::string(baseNameOf(printStorePath(drvPath)));
+    auto logPath = "log/" + std::string(baseNameOf(printStorePath(path)));
 
     debug("fetching build log from binary cache '%s/%s'", getUri(), logPath);
 
diff --git a/src/libstore/binary-cache-store.hh b/src/libstore/binary-cache-store.hh
index 8c82e2387..abd92a83c 100644
--- a/src/libstore/binary-cache-store.hh
+++ b/src/libstore/binary-cache-store.hh
@@ -129,7 +129,7 @@ public:
 
     void addSignatures(const StorePath & storePath, const StringSet & sigs) override;
 
-    std::optional<std::string> getBuildLog(const StorePath & path) override;
+    std::optional<std::string> getBuildLogExact(const StorePath & path) override;
 
     void addBuildLog(const StorePath & drvPath, std::string_view log) override;
 
diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 488e06d8c..752f9a4f3 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -1459,7 +1459,7 @@ struct RestrictedStore : public virtual RestrictedStoreConfig, public virtual Lo
             unknown, downloadSize, narSize);
     }
 
-    virtual std::optional<std::string> getBuildLog(const StorePath & path) override
+    virtual std::optional<std::string> getBuildLogExact(const StorePath & path) override
     { return std::nullopt; }
 
     virtual void addBuildLog(const StorePath & path, std::string_view log) override
diff --git a/src/libstore/local-fs-store.cc b/src/libstore/local-fs-store.cc
index c5ae7536f..b224fc3e9 100644
--- a/src/libstore/local-fs-store.cc
+++ b/src/libstore/local-fs-store.cc
@@ -87,20 +87,8 @@ void LocalFSStore::narFromPath(const StorePath & path, Sink & sink)
 
 const std::string LocalFSStore::drvsLogDir = "drvs";
 
-std::optional<std::string> LocalFSStore::getBuildLog(const StorePath & path_)
+std::optional<std::string> LocalFSStore::getBuildLogExact(const StorePath & path)
 {
-    auto path = path_;
-
-    if (!path.isDerivation()) {
-        try {
-            auto info = queryPathInfo(path);
-            if (!info->deriver) return std::nullopt;
-            path = *info->deriver;
-        } catch (InvalidPath &) {
-            return std::nullopt;
-        }
-    }
-
     auto baseName = path.to_string();
 
     for (int j = 0; j < 2; j++) {
diff --git a/src/libstore/local-fs-store.hh b/src/libstore/local-fs-store.hh
index e6fb3201a..947707341 100644
--- a/src/libstore/local-fs-store.hh
+++ b/src/libstore/local-fs-store.hh
@@ -50,7 +50,7 @@ public:
         return getRealStoreDir() + "/" + std::string(storePath, storeDir.size() + 1);
     }
 
-    std::optional<std::string> getBuildLog(const StorePath & path) override;
+    std::optional<std::string> getBuildLogExact(const StorePath & path) override;
 
 };
 
diff --git a/src/libstore/log-store.hh b/src/libstore/log-store.hh
index ff1b92e17..b807e3e71 100644
--- a/src/libstore/log-store.hh
+++ b/src/libstore/log-store.hh
@@ -11,7 +11,14 @@ struct LogStore : public virtual Store
 
     /* Return the build log of the specified store path, if available,
        or null otherwise. */
-    virtual std::optional<std::string> getBuildLog(const StorePath & path) = 0;
+    std::optional<std::string> getBuildLog(const StorePath & path) {
+      auto maybePath = getBuildDerivationPath(path);
+      if (!maybePath)
+          return std::nullopt;
+      return getBuildLogExact(maybePath.value());
+    }
+
+    virtual std::optional<std::string> getBuildLogExact(const StorePath & path) = 0;
 
     virtual void addBuildLog(const StorePath & path, std::string_view log) = 0;
 
diff --git a/src/libstore/ssh-store.cc b/src/libstore/ssh-store.cc
index 62daa838c..a1d4daafd 100644
--- a/src/libstore/ssh-store.cc
+++ b/src/libstore/ssh-store.cc
@@ -53,8 +53,8 @@ public:
     { return false; }
 
     // FIXME extend daemon protocol, move implementation to RemoteStore
-    std::optional<std::string> getBuildLog(const StorePath & path) override
-    { unsupported("getBuildLog"); }
+    std::optional<std::string> getBuildLogExact(const StorePath & path) override
+    { unsupported("getBuildLogExact"); }
 
 private:
 
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 426230ca5..f959dfd51 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -1301,6 +1301,34 @@ Derivation readDerivationCommon(Store& store, const StorePath& drvPath, bool req
     }
 }
 
+std::optional<StorePath> Store::getBuildDerivationPath(const StorePath & path)
+{
+
+    if (!path.isDerivation()) {
+        try {
+            auto info = queryPathInfo(path);
+            if (!info->deriver) return std::nullopt;
+            return *info->deriver;
+        } catch (InvalidPath &) {
+            return std::nullopt;
+        }
+    }
+
+    if (!settings.isExperimentalFeatureEnabled(Xp::CaDerivations) || !isValidPath(path))
+        return path;
+
+    auto drv = readDerivation(path);
+    if (!drv.type().hasKnownOutputPaths()) {
+        // The build log is actually attached to the corresponding
+        // resolved derivation, so we need to get it first
+        auto resolvedDrv = drv.tryResolve(*this);
+        if (resolvedDrv)
+            return writeDerivation(*this, *resolvedDrv, NoRepair, true);
+    }
+
+    return path;
+}
+
 Derivation Store::readDerivation(const StorePath & drvPath)
 { return readDerivationCommon(*this, drvPath, true); }
 
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 4a88d7216..a1c499249 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -618,6 +618,13 @@ public:
      */
     StorePathSet exportReferences(const StorePathSet & storePaths, const StorePathSet & inputPaths);
 
+    /**
+     * Given a store path, return the realisation actually used in the realisation of this path:
+     * - If the path is a content-addressed derivation, try to resolve it
+     * - Otherwise, find one of its derivers
+     */
+    std::optional<StorePath> getBuildDerivationPath(const StorePath &);
+
     /* Hack to allow long-running processes like hydra-queue-runner to
        occasionally flush their path info cache. */
     void clearPathInfoCache()