buildPaths(): Add an evalStore argument

With this, we don't have to copy the entire .drv closure to the
destination store ahead of time (or at all). Instead, buildPaths()
reads .drv files from the eval store and copies inputSrcs to the
destination store if it needs to build a derivation.

Issue #5025.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/libstore/build/worker.hh b/src/libstore/build/worker.hh
index 918de35f6..6a3b99c02 100644
--- a/src/libstore/build/worker.hh
+++ b/src/libstore/build/worker.hh
@@ -110,6 +110,7 @@ public:
     bool checkMismatch;
 
     Store & store;
+    Store & evalStore;
 
     std::unique_ptr<HookInstance> hook;
 
@@ -131,7 +132,7 @@ public:
        it answers with "decline-permanently", we don't try again. */
     bool tryBuildHook = true;
 
-    Worker(Store & store);
+    Worker(Store & store, Store & evalStore);
     ~Worker();
 
     /* Make a goal (with caching). */