From 49e272f6472360ba952aa4fa62cc8e61a1b4d6b7 Mon Sep 17 00:00:00 2001
From: Falco Peijnenburg <fpeijnenburg@gmail.com>
Date: Sat, 27 Oct 2018 18:12:02 +0200
Subject: [PATCH] copyStorePath: Fix hash errors when copying from older store

This commit partially reverts 48662d151bdf4a38670897beacea9d1bd750376a. When
copying from an older store (in my case a store running Nix 1.11.7), nix would
throw errors about there being no hash. This is fixed by recalculating the hash.
---
 src/libstore/store-api.cc | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 92e2685f7..dc54c735f 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -588,15 +588,19 @@ void copyStorePath(ref<Store> srcStore, ref<Store> dstStore,
 
     uint64_t total = 0;
 
-    // FIXME
-#if 0
     if (!info->narHash) {
+        StringSink sink;
+        srcStore->narFromPath({storePath}, sink);
         auto info2 = make_ref<ValidPathInfo>(*info);
         info2->narHash = hashString(htSHA256, *sink.s);
         if (!info->narSize) info2->narSize = sink.s->size();
+        if (info->ultimate) info2->ultimate = false;
         info = info2;
+
+        StringSource source(*sink.s);
+        dstStore->addToStore(*info, source, repair, checkSigs);
+        return;
     }
-#endif
 
     if (info->ultimate) {
         auto info2 = make_ref<ValidPathInfo>(*info);