Merge pull request #9157 from obsidiansystems/protocol-versions

Add protocol versions to `{Worker,Serve}Proto::*Conn`

(cherry picked from commit 4d17c59d8d059a5b39f1d1da2b58f2ec8da44861)
Change-Id: I497af39deb792e50c157a1305d8c9e722798740b

7 files changed, 58 insertions, 27 deletions

diff --git a/src/libstore/daemon.cc b/src/libstore/daemon.cc
index 8cbf6f044..d61e97a64 100644
--- a/src/libstore/daemon.cc
+++ b/src/libstore/daemon.cc
@@ -45,9 +45,9 @@ struct TunnelLogger : public Logger
 
     Sync<State> state_;
 
-    unsigned int clientVersion;
+    WorkerProto::Version clientVersion;
 
-    TunnelLogger(FdSink & to, unsigned int clientVersion)
+    TunnelLogger(FdSink & to, WorkerProto::Version clientVersion)
         : to(to), clientVersion(clientVersion) { }
 
     void enqueueMsg(const std::string & s)
@@ -261,7 +261,7 @@ struct ClientSettings
     }
 };
 
-static std::vector<DerivedPath> readDerivedPaths(Store & store, unsigned int clientVersion, WorkerProto::ReadConn conn)
+static std::vector<DerivedPath> readDerivedPaths(Store & store, WorkerProto::Version clientVersion, WorkerProto::ReadConn conn)
 {
     std::vector<DerivedPath> reqs;
     if (GET_PROTOCOL_MINOR(clientVersion) >= 30) {
@@ -274,11 +274,17 @@ static std::vector<DerivedPath> readDerivedPaths(Store & store, unsigned int cli
 }
 
 static void performOp(TunnelLogger * logger, ref<Store> store,
-    TrustedFlag trusted, RecursiveFlag recursive, unsigned int clientVersion,
+    TrustedFlag trusted, RecursiveFlag recursive, WorkerProto::Version clientVersion,
     Source & from, BufferedSink & to, WorkerProto::Op op)
 {
-    WorkerProto::ReadConn rconn { .from = from };
-    WorkerProto::WriteConn wconn { .to = to };
+    WorkerProto::ReadConn rconn {
+        .from = from,
+        .version = clientVersion,
+    };
+    WorkerProto::WriteConn wconn {
+        .to = to,
+        .version = clientVersion,
+    };
 
     switch (op) {
 
@@ -1017,7 +1023,7 @@ void processConnection(
     if (magic != WORKER_MAGIC_1) throw Error("protocol mismatch");
     to << WORKER_MAGIC_2 << PROTOCOL_VERSION;
     to.flush();
-    unsigned int clientVersion = readInt(from);
+    WorkerProto::Version clientVersion = readInt(from);
 
     if (clientVersion < 0x10a)
         throw Error("the Nix client version is too old");
@@ -1052,7 +1058,10 @@ void processConnection(
         auto temp = trusted
             ? store->isTrustedClient()
             : std::optional { NotTrusted };
-        WorkerProto::WriteConn wconn { .to = to };
+        WorkerProto::WriteConn wconn {
+            .to = to,
+            .version = clientVersion,
+        };
         WorkerProto::write(*store, wconn, temp);
     }
 
diff --git a/src/libstore/legacy-ssh-store.cc b/src/libstore/legacy-ssh-store.cc
index 703ded0b2..9143be72e 100644
--- a/src/libstore/legacy-ssh-store.cc
+++ b/src/libstore/legacy-ssh-store.cc
@@ -45,7 +45,7 @@ struct LegacySSHStore : public virtual LegacySSHStoreConfig, public virtual Stor
         std::unique_ptr<SSHMaster::Connection> sshConn;
         FdSink to;
         FdSource from;
-        int remoteVersion;
+        ServeProto::Version remoteVersion;
         bool good = true;
 
         /**
@@ -60,6 +60,7 @@ struct LegacySSHStore : public virtual LegacySSHStoreConfig, public virtual Stor
         {
             return ServeProto::ReadConn {
                 .from = from,
+                .version = remoteVersion,
             };
         }
 
@@ -75,6 +76,7 @@ struct LegacySSHStore : public virtual LegacySSHStoreConfig, public virtual Stor
         {
             return ServeProto::WriteConn {
                 .to = to,
+                .version = remoteVersion,
             };
         }
     };
diff --git a/src/libstore/path-info.cc b/src/libstore/path-info.cc
index ccb57104f..a9231ce8d 100644
--- a/src/libstore/path-info.cc
+++ b/src/libstore/path-info.cc
@@ -141,7 +141,10 @@ ValidPathInfo ValidPathInfo::read(Source & source, const Store & store, unsigned
     ValidPathInfo info(path, narHash);
     if (deriver != "") info.deriver = store.parseStorePath(deriver);
     info.references = WorkerProto::Serialise<StorePathSet>::read(store,
-        WorkerProto::ReadConn { .from = source });
+        WorkerProto::ReadConn {
+            .from = source,
+            .version = format,
+        });
     source >> info.registrationTime >> info.narSize;
     if (format >= 16) {
         source >> info.ultimate;
@@ -163,7 +166,10 @@ void ValidPathInfo::write(
     sink << (deriver ? store.printStorePath(*deriver) : "")
          << narHash.to_string(Base16, false);
     WorkerProto::write(store,
-        WorkerProto::WriteConn { .to = sink },
+        WorkerProto::WriteConn {
+            .to = sink,
+            .version = format,
+        },
         references);
     sink << registrationTime << narSize;
     if (format >= 16) {
diff --git a/src/libstore/remote-store-connection.hh b/src/libstore/remote-store-connection.hh
index ce4740a9c..e4a9cacb9 100644
--- a/src/libstore/remote-store-connection.hh
+++ b/src/libstore/remote-store-connection.hh
@@ -30,7 +30,7 @@ struct RemoteStore::Connection
      * sides support. (If the maximum doesn't exist, we would fail to
      * establish a connection and produce a value of this type.)
      */
-    unsigned int daemonVersion;
+    WorkerProto::Version daemonVersion;
 
     /**
      * Whether the remote side trusts us or not.
@@ -70,6 +70,7 @@ struct RemoteStore::Connection
     {
         return WorkerProto::ReadConn {
             .from = from,
+            .version = daemonVersion,
         };
     }
 
@@ -85,6 +86,7 @@ struct RemoteStore::Connection
     {
         return WorkerProto::WriteConn {
             .to = to,
+            .version = daemonVersion,
         };
     }
 
diff --git a/src/libstore/serve-protocol.hh b/src/libstore/serve-protocol.hh
index e2345d450..a627c6ad6 100644
--- a/src/libstore/serve-protocol.hh
+++ b/src/libstore/serve-protocol.hh
@@ -31,25 +31,28 @@ struct ServeProto
     enum struct Command : uint64_t;
 
     /**
+     * Version type for the protocol.
+     *
+     * @todo Convert to struct with separate major vs minor fields.
+     */
+    using Version = unsigned int;
+
+    /**
      * A unidirectional read connection, to be used by the read half of the
      * canonical serializers below.
-     *
-     * This currently is just a `Source &`, but more fields will be added
-     * later.
      */
     struct ReadConn {
         Source & from;
+        Version version;
     };
 
     /**
      * A unidirectional write connection, to be used by the write half of the
      * canonical serializers below.
-     *
-     * This currently is just a `Sink &`, but more fields will be added
-     * later.
      */
     struct WriteConn {
         Sink & to;
+        Version version;
     };
 
     /**
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index c84060103..2d55d926a 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -48,25 +48,28 @@ struct WorkerProto
     enum struct Op : uint64_t;
 
     /**
+     * Version type for the protocol.
+     *
+     * @todo Convert to struct with separate major vs minor fields.
+     */
+    using Version = unsigned int;
+
+    /**
      * A unidirectional read connection, to be used by the read half of the
      * canonical serializers below.
-     *
-     * This currently is just a `Source &`, but more fields will be added
-     * later.
      */
     struct ReadConn {
         Source & from;
+        Version version;
     };
 
     /**
      * A unidirectional write connection, to be used by the write half of the
      * canonical serializers below.
-     *
-     * This currently is just a `Sink &`, but more fields will be added
-     * later.
      */
     struct WriteConn {
         Sink & to;
+        Version version;
     };
 
     /**
diff --git a/src/nix-store/nix-store.cc b/src/nix-store/nix-store.cc
index 9b6c80a75..11d2e86e3 100644
--- a/src/nix-store/nix-store.cc
+++ b/src/nix-store/nix-store.cc
@@ -818,10 +818,16 @@ static void opServe(Strings opFlags, Strings opArgs)
     if (magic != SERVE_MAGIC_1) throw Error("protocol mismatch");
     out << SERVE_MAGIC_2 << SERVE_PROTOCOL_VERSION;
     out.flush();
-    unsigned int clientVersion = readInt(in);
+    ServeProto::Version clientVersion = readInt(in);
 
-    ServeProto::ReadConn rconn { .from = in };
-    ServeProto::WriteConn wconn { .to = out };
+    ServeProto::ReadConn rconn {
+        .from = in,
+        .version = clientVersion,
+    };
+    ServeProto::WriteConn wconn {
+        .to = out,
+        .version = clientVersion,
+    };
 
     auto getBuildSettings = [&]() {
         // FIXME: changing options here doesn't work if we're