RemoteStore::addToStore(): Pass content-addressability assertion

... and use this in Downloader::downloadCached(). This fixes

  $ nix-build https://nixos.org/channels/nixos-16.09-small/nixexprs.tar.xz -A hello
  error: cannot import path ‘/nix/store/csfbp1s60dkgmk9f8g0zk0mwb7hzgabd-nixexprs.tar.xz’ because it lacks a valid signature

5 files changed, 15 insertions, 3 deletions

diff --git a/src/libstore/download.cc b/src/libstore/download.cc
index 25ccd7d0b526..a56fd6922a5c 100644
--- a/src/libstore/download.cc
+++ b/src/libstore/download.cc
@@ -612,6 +612,7 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
                 Hash hash = hashString(expectedHash ? expectedHash.type : htSHA256, *res.data);
                 info.path = store->makeFixedOutputPath(false, hash, name);
                 info.narHash = hashString(htSHA256, *sink.s);
+                info.ca = makeFixedOutputCA(false, hash);
                 store->addToStore(info, sink.s, false, true);
                 storePath = info.path;
             }
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 4c161cfb341f..9b775e16a387 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -1002,7 +1002,7 @@ Path LocalStore::addToStoreFromDump(const string & dump, const string & name,
             info.narHash = hash.first;
             info.narSize = hash.second;
             info.ultimate = true;
-            info.ca = "fixed:" + (recursive ? (std::string) "r:" : "") + h.to_string();
+            info.ca = makeFixedOutputCA(recursive, h);
             registerValidPath(info);
         }
 
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index 42c09ec7e0b6..7f398685a2c1 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -380,7 +380,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, const ref<std::string>
         conn->to << wopAddToStoreNar
                  << info.path << info.deriver << printHash(info.narHash)
                  << info.references << info.registrationTime << info.narSize
-                 << info.ultimate << info.sigs << *nar << repair << dontCheckSigs;
+                 << info.ultimate << info.sigs << info.ca << *nar << repair << dontCheckSigs;
         // FIXME: don't send nar as a string
         conn->processStderr();
     }
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index b5934a0d1232..401b001b2d8f 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -676,6 +676,12 @@ Strings ValidPathInfo::shortRefs() const
 }
 
 
+std::string makeFixedOutputCA(bool recursive, const Hash & hash)
+{
+    return "fixed:" + (recursive ? (std::string) "r:" : "") + hash.to_string();
+}
+
+
 }
 
 
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index d03e70849f93..c344b9d66ed3 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -128,7 +128,7 @@ struct ValidPathInfo
        of an output path of a derivation were actually produced by
        that derivation. In the intensional model, we have to trust
        that a particular output path was produced by a derivation; the
-       path name then implies the contents.)
+       path then implies the contents.)
 
        Ideally, the content-addressability assertion would just be a
        Boolean, and the store path would be computed from
@@ -687,6 +687,11 @@ ValidPathInfo decodeValidPathInfo(std::istream & str,
     bool hashGiven = false);
 
 
+/* Compute the content-addressability assertion (ValidPathInfo::ca)
+   for paths created by makeFixedOutputPath() / addToStore(). */
+std::string makeFixedOutputCA(bool recursive, const Hash & hash);
+
+
 MakeError(SubstError, Error)
 MakeError(BuildError, Error) /* denotes a permanent build failure */
 MakeError(InvalidPath, Error)