Fix compilation against Nix 2.16

configure.ac

@@ -10,8 +10,6 @@ AC_PROG_LN_S
 AC_PROG_LIBTOOL
 AC_PROG_CXX
 
-CXXFLAGS+=" -std=c++17"
-
 AC_PATH_PROG([XSLTPROC], [xsltproc])
 
 AC_ARG_WITH([docbook-xsl],

src/hydra-eval-jobs/hydra-eval-jobs.cc

@@ -25,7 +25,8 @@
 
 #include <nlohmann/json.hpp>
 
-void check_pid_status_nonblocking(pid_t check_pid) {
+void check_pid_status_nonblocking(pid_t check_pid)
+{
     // Only check 'initialized' and known PID's
     if (check_pid <= 0) { return; }
 
@@ -100,7 +101,7 @@ static std::string queryMetaStrings(EvalState & state, DrvInfo & drv, const std:
         else if (v.type() == nAttrs) {
             auto a = v.attrs->find(state.symbols.create(subAttribute));
             if (a != v.attrs->end())
-                res.push_back(std::string(state.forceString(*a->value)));
+                res.push_back(std::string(state.forceString(*a->value, a->pos, "while evaluating meta attributes")));
         }
     };
 
@@ -197,26 +198,30 @@ static void worker(
 
                 /* If this is an aggregate, then get its constituents. */
                 auto a = v->attrs->get(state.symbols.create("_hydraAggregate"));
-                if (a && state.forceBool(*a->value, a->pos)) {
+                if (a && state.forceBool(*a->value, a->pos, "while evaluating the `_hydraAggregate` attribute")) {
                     auto a = v->attrs->get(state.symbols.create("constituents"));
                     if (!a)
                         throw EvalError("derivation must have a ‘constituents’ attribute");
 
+                    NixStringContext context;
+                    state.coerceToString(a->pos, *a->value, context, "while evaluating the `constituents` attribute", true, false);
+                    for (auto & c : context)
+                        std::visit(overloaded {
+                            [&](const NixStringContextElem::Built & b) {
+                                job["constituents"].push_back(state.store->printStorePath(b.drvPath));
+                            },
+                            [&](const NixStringContextElem::Opaque & o) {
+                            },
+                            [&](const NixStringContextElem::DrvDeep & d) {
+                            },
+                        }, c.raw());
 
-                    PathSet context;
+                    state.forceList(*a->value, a->pos, "while evaluating the `constituents` attribute");
-                    state.coerceToString(a->pos, *a->value, context, true, false);
-                    for (auto & i : context)
-                        if (i.at(0) == '!') {
-                            size_t index = i.find("!", 1);
-                            job["constituents"].push_back(std::string(i, index + 1));
-                        }
-
-                    state.forceList(*a->value, a->pos);
                     for (unsigned int n = 0; n < a->value->listSize(); ++n) {
                         auto v = a->value->listElems()[n];
                         state.forceValue(*v, noPos);
                         if (v->type() == nString)
-                            job["namedConstituents"].push_back(state.forceStringNoCtx(*v));
+                            job["namedConstituents"].push_back(v->str());
                     }
                 }
 

src/hydra-queue-runner/build-remote.cc

@@ -116,12 +116,12 @@ static void copyClosureTo(std::timed_mutex & sendMutex, Store & destStore,
        the remote host to substitute missing paths. */
     // FIXME: substitute output pollutes our build log
     to << cmdQueryValidPaths << 1 << useSubstitutes;
-    worker_proto::write(destStore, to, closure);
+    workerProtoWrite(destStore, to, closure);
     to.flush();
 
     /* Get back the set of paths that are already valid on the remote
        host. */
-    auto present = worker_proto::read(destStore, from, Phantom<StorePathSet> {});
+    auto present = WorkerProto<StorePathSet>::read(destStore, from);
 
     if (present.size() == closure.size()) return;
 
@@ -367,7 +367,7 @@ void State::buildRemote(ref<Store> destStore,
             }
         }
         if (GET_PROTOCOL_MINOR(remoteVersion) >= 6) {
-            worker_proto::read(*localStore, from, Phantom<DrvOutputs> {});
+            WorkerProto<DrvOutputs>::read(*localStore, from);
         }
         switch ((BuildResult::Status) res) {
             case BuildResult::Built:
@@ -444,17 +444,17 @@ void State::buildRemote(ref<Store> destStore,
             std::map<StorePath, ValidPathInfo> infos;
             size_t totalNarSize = 0;
             to << cmdQueryPathInfos;
-            worker_proto::write(*localStore, to, outputs);
+            workerProtoWrite(*localStore, to, outputs);
             to.flush();
             while (true) {
                 auto storePathS = readString(from);
                 if (storePathS == "") break;
                 auto deriver = readString(from); // deriver
-                auto references = worker_proto::read(*localStore, from, Phantom<StorePathSet> {});
+                auto references = WorkerProto<StorePathSet>::read(*localStore, from);
                 readLongLong(from); // download size
                 auto narSize = readLongLong(from);
                 auto narHash = Hash::parseAny(readString(from), htSHA256);
-                auto ca = parseContentAddressOpt(readString(from));
+                auto ca = ContentAddress::parseOpt(readString(from));
                 readStrings<StringSet>(from); // sigs
                 ValidPathInfo info(localStore->parseStorePath(storePathS), narHash);
                 assert(outputs.count(info.path));

src/hydra-queue-runner/builder.cc

@@ -323,7 +323,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
                 pqxx::work txn(*conn);
 
                 for (auto & b : direct) {
-                    printMsg(lvlInfo, format("marking build %1% as succeeded") % b->id);
+                    printInfo("marking build %1% as succeeded", b->id);
                     markSucceededBuild(txn, b, res, buildId != b->id || result.isCached,
                         result.startTime, result.stopTime);
                 }
@@ -451,7 +451,7 @@ void State::failStep(
             /* Mark all builds that depend on this derivation as failed. */
             for (auto & build : indirect) {
                 if (build->finishedInDB) continue;
-                printMsg(lvlError, format("marking build %1% as failed") % build->id);
+                printError("marking build %1% as failed", build->id);
                 txn.exec_params0
                     ("update Builds set finished = 1, buildStatus = $2, startTime = $3, stopTime = $4, isCachedBuild = $5, notificationPendingSince = $4 where id = $1 and finished = 0",
                      build->id,

src/hydra-queue-runner/dispatcher.cc

@@ -52,7 +52,7 @@ void State::dispatcher()
             {
                 auto dispatcherWakeup_(dispatcherWakeup.lock());
                 if (!*dispatcherWakeup_) {
-                    printMsg(lvlDebug, format("dispatcher sleeping for %1%s") %
+                    debug("dispatcher sleeping for %1%s",
                         std::chrono::duration_cast<std::chrono::seconds>(sleepUntil - std::chrono::system_clock::now()).count());
                     dispatcherWakeup_.wait_until(dispatcherWakeupCV, sleepUntil);
                 }
@@ -60,7 +60,7 @@ void State::dispatcher()
             }
 
         } catch (std::exception & e) {
-            printMsg(lvlError, format("dispatcher: %1%") % e.what());
+            printError("dispatcher: %s", e.what());
             sleep(1);
         }
 
@@ -80,8 +80,8 @@ system_time State::doDispatch()
             jobset.second->pruneSteps();
             auto s2 = jobset.second->shareUsed();
             if (s1 != s2)
-                printMsg(lvlDebug, format("pruned scheduling window of ‘%1%:%2%’ from %3% to %4%")
+                debug("pruned scheduling window of ‘%1%:%2%’ from %3% to %4%",
-                    % jobset.first.first % jobset.first.second % s1 % s2);
+                    jobset.first.first, jobset.first.second, s1, s2);
         }
     }
 

src/hydra-queue-runner/hydra-queue-runner.cc

@@ -161,9 +161,9 @@ void State::parseMachines(const std::string & contents)
            same name. */
         auto i = oldMachines.find(machine->sshName);
         if (i == oldMachines.end())
-            printMsg(lvlChatty, format("adding new machine ‘%1%’") % machine->sshName);
+            printMsg(lvlChatty, "adding new machine ‘%1%’", machine->sshName);
         else
-            printMsg(lvlChatty, format("updating machine ‘%1%’") % machine->sshName);
+            printMsg(lvlChatty, "updating machine ‘%1%’", machine->sshName);
         machine->state = i == oldMachines.end()
             ? std::make_shared<Machine::State>()
             : i->second->state;
@@ -173,7 +173,7 @@ void State::parseMachines(const std::string & contents)
     for (auto & m : oldMachines)
         if (newMachines.find(m.first) == newMachines.end()) {
             if (m.second->enabled)
-                printMsg(lvlInfo, format("removing machine ‘%1%’") % m.first);
+                printInfo("removing machine ‘%1%’", m.first);
             /* Add a disabled Machine object to make sure stats are
                maintained. */
             auto machine = std::make_shared<Machine>(*(m.second));
@@ -928,7 +928,6 @@ int main(int argc, char * * argv)
         });
 
         settings.verboseBuild = true;
-        settings.lockCPU = false;
 
         State state{metricsAddrOpt};
         if (status)

src/hydra-queue-runner/queue-monitor.cc

@@ -13,7 +13,7 @@ void State::queueMonitor()
         try {
             queueMonitorLoop();
         } catch (std::exception & e) {
-            printMsg(lvlError, format("queue monitor: %1%") % e.what());
+            printError("queue monitor: %s", e.what());
             sleep(10); // probably a DB problem, so don't retry right away
         }
     }
@@ -142,13 +142,13 @@ bool State::getQueuedBuilds(Connection & conn,
 
     createBuild = [&](Build::ptr build) {
         prom.queue_build_loads.Increment();
-        printMsg(lvlTalkative, format("loading build %1% (%2%)") % build->id % build->fullJobName());
+        printMsg(lvlTalkative, "loading build %1% (%2%)", build->id, build->fullJobName());
         nrAdded++;
         newBuildsByID.erase(build->id);
 
         if (!localStore->isValidPath(build->drvPath)) {
             /* Derivation has been GC'ed prematurely. */
-            printMsg(lvlError, format("aborting GC'ed build %1%") % build->id);
+            printError("aborting GC'ed build %1%", build->id);
             if (!build->finishedInDB) {
                 auto mc = startDbUpdate();
                 pqxx::work txn(conn);
@@ -302,7 +302,7 @@ bool State::getQueuedBuilds(Connection & conn,
 
         /* Add the new runnable build steps to ‘runnable’ and wake up
            the builder threads. */
-        printMsg(lvlChatty, format("got %1% new runnable steps from %2% new builds") % newRunnable.size() % nrAdded);
+        printMsg(lvlChatty, "got %1% new runnable steps from %2% new builds", newRunnable.size(), nrAdded);
         for (auto & r : newRunnable)
             makeRunnable(r);
 
@@ -358,13 +358,13 @@ void State::processQueueChange(Connection & conn)
         for (auto i = builds_->begin(); i != builds_->end(); ) {
             auto b = currentIds.find(i->first);
             if (b == currentIds.end()) {
-                printMsg(lvlInfo, format("discarding cancelled build %1%") % i->first);
+                printInfo("discarding cancelled build %1%", i->first);
                 i = builds_->erase(i);
                 // FIXME: ideally we would interrupt active build steps here.
                 continue;
             }
             if (i->second->globalPriority < b->second) {
-                printMsg(lvlInfo, format("priority of build %1% increased") % i->first);
+                printInfo("priority of build %1% increased", i->first);
                 i->second->globalPriority = b->second;
                 i->second->propagatePriorities();
             }
@@ -654,7 +654,7 @@ BuildOutput State::getBuildOutputCached(Connection & conn, nix::ref<nix::Store>
         if (r.empty()) continue;
         BuildID id = r[0][0].as<BuildID>();
 
-        printMsg(lvlInfo, format("reusing build %d") % id);
+        printInfo("reusing build %d", id);
 
         BuildOutput res;
         res.failed = r[0][1].as<int>() == bsFailedWithOutput;