libstore: remove flushing from processStderr

it's part of sending the command and should be treated as such.

Change-Id: I7406ead5cd08c79efe50f3b0fcb522a18d9d7bcf

lix/libstore/remote-store-connection.hh

@@ -97,7 +97,7 @@ struct RemoteStore::Connection
 
     virtual ~Connection();
 
-    std::exception_ptr processStderr(bool flush = true);
+    std::exception_ptr processStderr();
 };
 
 /**
@@ -134,7 +134,7 @@ struct RemoteStore::ConnectionHandle
     RemoteStore::Connection & operator * () { return *handle; }
     RemoteStore::Connection * operator -> () { return &*handle; }
 
-    void processStderr(bool flush = true);
+    void processStderr();
 
     kj::Promise<Result<void>>
     withFramedSinkAsync(std::function<kj::Promise<Result<void>>(Sink & sink)> fun);
@@ -153,6 +153,7 @@ struct RemoteStore::ConnectionHandle
         // the subframing layer (which is then responsible for any error handling)
         if constexpr (requires { handle->to << std::declval<LastArgT>(); }) {
             ((handle->to << std::forward<Args>(args)), ...);
+            handle->to.flush();
             processStderr();
         } else {
             using ImmediateArgsIdxs = std::make_index_sequence<sizeof...(Args) - 1>;
@@ -160,6 +161,7 @@ struct RemoteStore::ConnectionHandle
 
             [&]<size_t... Ids>(std::integer_sequence<size_t, Ids...>) {
                 ((handle->to << std::get<Ids>(std::forward<AllArgsT>(allArgs))), ...);
+                handle->to.flush();
             }(ImmediateArgsIdxs{});
 
             LIX_TRY_AWAIT(withFramedSinkAsync(std::get<LastArgIdx>(allArgs)));

lix/libstore/remote-store.cc

@@ -154,6 +154,7 @@ void RemoteStore::setOptions(Connection & conn)
         command << i.first << i.second.value;
 
     StringSource{command.s}.drainInto(conn.to);
+    conn.to.flush();
     auto ex = conn.processStderr();
     if (ex) std::rethrow_exception(ex);
 }
@@ -167,9 +168,9 @@ RemoteStore::ConnectionHandle::~ConnectionHandle()
     }
 }
 
-void RemoteStore::ConnectionHandle::processStderr(bool flush)
+void RemoteStore::ConnectionHandle::processStderr()
 {
-    auto ex = handle->processStderr(flush);
+    auto ex = handle->processStderr();
     if (ex) {
         daemonException = true;
         std::rethrow_exception(ex);
@@ -742,11 +743,8 @@ static Logger::Fields readFields(Source & from)
 }
 
 
-std::exception_ptr RemoteStore::Connection::processStderr(bool flush)
+std::exception_ptr RemoteStore::Connection::processStderr()
 {
-    if (flush)
-        to.flush();
-
     while (true) {
 
         auto msg = readNum<uint64_t>(from);
@@ -795,13 +793,12 @@ RemoteStore::ConnectionHandle::FramedSinkHandler::FramedSinkHandler(
 )
     : stderrHandler([&]() {
         try {
-            conn.processStderr(false);
+            conn.processStderr();
         } catch (...) {
             ex = std::current_exception();
         }
     })
 {
-    conn.handle->to.flush();
     handlerThreads.enqueue([&] { stderrHandler(); });
 }