treewide: clang-tidy modernize

Fix some trivial findings throughout the codebase, mostly making
implicit casts explicit.

.clang-tidy

@@ -0,0 +1,12 @@
+UseColor: true
+Checks:
+  - -*
+
+  - bugprone-*
+    # kind of nonsense
+  - -bugprone-easily-swappable-parameters
+    # many warnings due to not recognizing `assert` properly
+  - -bugprone-unchecked-optional-access
+
+  - modernize-*
+  - -modernize-use-trailing-return-type

src/hydra-evaluator/hydra-evaluator.cc

@@ -14,11 +14,12 @@
 #include <sys/wait.h>
 
 #include <boost/format.hpp>
+#include <utility>
 
 using namespace nix;
 using boost::format;
 
-typedef std::pair<std::string, std::string> JobsetName;
+using JobsetName = std::pair<std::string, std::string>;
 
 class JobsetId {
     public:
@@ -28,8 +29,8 @@ class JobsetId {
     int id;
 
 
-    JobsetId(const std::string & project, const std::string & jobset, int id)
+    JobsetId(std::string  project, std::string  jobset, int id)
-        : project{ project }, jobset{ jobset }, id{ id }
+        : project{std::move( project )}, jobset{std::move( jobset )}, id{ id }
     {
     }
 
@@ -41,7 +42,7 @@ class JobsetId {
     friend bool operator== (const JobsetId & lhs, const JobsetName & rhs);
     friend bool operator!= (const JobsetId & lhs, const JobsetName & rhs);
 
-    std::string display() const {
+    [[nodiscard]] std::string display() const {
         return str(format("%1%:%2% (jobset#%3%)") % project % jobset % id);
     }
 };
@@ -88,11 +89,11 @@ struct Evaluator
         JobsetId name;
         std::optional<EvaluationStyle> evaluation_style;
         time_t lastCheckedTime, triggerTime;
-        int checkInterval;
+        time_t checkInterval;
         Pid pid;
     };
 
-    typedef std::map<JobsetId, Jobset> Jobsets;
+    using Jobsets = std::map<JobsetId, Jobset>;
 
     std::optional<JobsetName> evalOne;
 
@@ -138,13 +139,15 @@ struct Evaluator
 
             if (evalOne && name != *evalOne) continue;
 
-            auto res = state->jobsets.try_emplace(name, Jobset{name});
+            auto res = state->jobsets.try_emplace(name, Jobset{.name=name});
 
             auto & jobset = res.first->second;
             jobset.lastCheckedTime = row["lastCheckedTime"].as<time_t>(0);
             jobset.triggerTime = row["triggerTime"].as<time_t>(notTriggered);
             jobset.checkInterval = row["checkInterval"].as<time_t>();
-            switch (row["jobset_enabled"].as<int>(0)) {
+
+            int eval_style = row["jobset_enabled"].as<int>(0);
+            switch (eval_style) {
                 case 1:
                     jobset.evaluation_style = EvaluationStyle::SCHEDULE;
                     break;
@@ -154,6 +157,9 @@ struct Evaluator
                 case 3:
                     jobset.evaluation_style = EvaluationStyle::ONE_AT_A_TIME;
                     break;
+                default:
+                    // Disabled or unknown. Leave as nullopt.
+                    break;
             }
 
             seen.insert(name);
@@ -175,7 +181,7 @@ struct Evaluator
 
     void startEval(State & state, Jobset & jobset)
     {
-        time_t now = time(0);
+        time_t now = time(nullptr);
 
         printInfo("starting evaluation of jobset ‘%s’ (last checked %d s ago)",
             jobset.name.display(),
@@ -228,7 +234,7 @@ struct Evaluator
             return false;
         }
 
-        if (jobset.lastCheckedTime + jobset.checkInterval <= time(0)) {
+        if (jobset.lastCheckedTime + jobset.checkInterval <= time(nullptr)) {
             // Time to schedule a fresh evaluation. If the jobset
             // is a ONE_AT_A_TIME jobset, ensure the previous jobset
             // has no remaining, unfinished work.
@@ -301,7 +307,7 @@ struct Evaluator
 
         /* Put jobsets in order of ascending trigger time, last checked
            time, and name. */
-        std::sort(sorted.begin(), sorted.end(),
+        std::ranges::sort(sorted,
             [](const Jobsets::iterator & a, const Jobsets::iterator & b) {
                 return
                     a->second.triggerTime != b->second.triggerTime
@@ -324,7 +330,7 @@ struct Evaluator
 
         while (true) {
 
-            time_t now = time(0);
+            time_t now = time(nullptr);
 
             std::chrono::seconds sleepTime = std::chrono::seconds::max();
 
@@ -411,7 +417,7 @@ struct Evaluator
                         printInfo("evaluation of jobset ‘%s’ %s",
                             jobset.name.display(), statusToString(status));
 
-                        auto now = time(0);
+                        auto now = time(nullptr);
 
                         jobset.triggerTime = notTriggered;
                         jobset.lastCheckedTime = now;

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

@@ -1,5 +1,6 @@
 #include <algorithm>
 #include <cmath>
+#include <ranges>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -41,6 +42,7 @@ static Strings extraStoreArgs(std::string & machine)
         }
     } catch (BadURL &) {
         // We just try to continue with `machine->sshName` here for backwards compat.
+        printMsg(lvlWarn, "could not parse machine URL '%s', passing through to SSH", machine);
     }
 
     return result;
@@ -133,8 +135,8 @@ static void copyClosureTo(
     auto sorted = destStore.topoSortPaths(closure);
 
     StorePathSet missing;
-    for (auto i = sorted.rbegin(); i != sorted.rend(); ++i)
+    for (auto & i : std::ranges::reverse_view(sorted))
-        if (!present.count(*i)) missing.insert(*i);
+        if (!present.count(i)) missing.insert(i);
 
     printMsg(lvlDebug, "sending %d missing paths", missing.size());
 
@@ -304,12 +306,12 @@ static BuildResult performBuild(
 
     time_t startTime, stopTime;
 
-    startTime = time(0);
+    startTime = time(nullptr);
     {
         MaintainCount<counter> mc(nrStepsBuilding);
         result = ServeProto::Serialise<BuildResult>::read(localStore, conn);
     }
-    stopTime = time(0);
+    stopTime = time(nullptr);
 
     if (!result.startTime) {
         // If the builder gave `startTime = 0`, use our measurements
@@ -338,10 +340,10 @@ static BuildResult performBuild(
             // were known
             assert(outputPath);
             auto outputHash = outputHashes.at(outputName);
-            auto drvOutput = DrvOutput { outputHash, outputName };
+            auto drvOutput = DrvOutput { .drvHash=outputHash, .outputName=outputName };
             result.builtOutputs.insert_or_assign(
                 std::move(outputName),
-                Realisation { drvOutput, *outputPath });
+                Realisation { .id=drvOutput, .outPath=*outputPath });
         }
     }
 
@@ -634,7 +636,7 @@ void State::buildRemote(ref<Store> destStore,
          * copying outputs and we end up building too many things that we
          * haven't been able to allow copy slots for. */
         assert(reservation.unique());
-        reservation = 0;
+        reservation = nullptr;
         wakeDispatcher();
 
         StorePathSet outputs;
@@ -697,7 +699,7 @@ void State::buildRemote(ref<Store> destStore,
         if (info->consecutiveFailures == 0 || info->lastFailure < now - std::chrono::seconds(30)) {
             info->consecutiveFailures = std::min(info->consecutiveFailures + 1, (unsigned int) 4);
             info->lastFailure = now;
-            int delta = retryInterval * std::pow(retryBackoff, info->consecutiveFailures - 1) + (rand() % 30);
+            int delta = static_cast<int>(retryInterval * std::pow(retryBackoff, info->consecutiveFailures - 1) + (rand() % 30));
             printMsg(lvlInfo, "will disable machine ‘%1%’ for %2%s", machine->sshName, delta);
             info->disabledUntil = now + std::chrono::seconds(delta);
         }

src/hydra-queue-runner/builder.cc

@@ -58,7 +58,7 @@ void State::builder(MachineReservation::ptr reservation)
     /* If the machine hasn't been released yet, release and wake up the dispatcher. */
     if (reservation) {
         assert(reservation.unique());
-        reservation = 0;
+        reservation = nullptr;
         wakeDispatcher();
     }
 
@@ -72,7 +72,7 @@ void State::builder(MachineReservation::ptr reservation)
             step_->tries++;
             nrRetries++;
             if (step_->tries > maxNrRetries) maxNrRetries = step_->tries; // yeah yeah, not atomic
-            int delta = retryInterval * std::pow(retryBackoff, step_->tries - 1) + (rand() % 10);
+            int delta = static_cast<int>(retryInterval * std::pow(retryBackoff, step_->tries - 1) + (rand() % 10));
             printMsg(lvlInfo, "will retry ‘%s’ after %ss", localStore->printStorePath(step->drvPath), delta);
             step_->after = std::chrono::system_clock::now() + std::chrono::seconds(delta);
         }
@@ -190,7 +190,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
         }
     });
 
-    time_t stepStartTime = result.startTime = time(0);
+    time_t stepStartTime = result.startTime = time(nullptr);
 
     /* If any of the outputs have previously failed, then don't bother
        building again. */
@@ -237,7 +237,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
         }
     }
 
-    time_t stepStopTime = time(0);
+    time_t stepStopTime = time(nullptr);
     if (!result.stopTime) result.stopTime = stepStopTime;
 
     /* For standard failures, we don't care about the error
@@ -251,7 +251,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
         auto step_(step->state.lock());
         if (!step_->jobsets.empty()) {
             // FIXME: loss of precision.
-            time_t charge = (result.stopTime - result.startTime) / step_->jobsets.size();
+            time_t charge = (result.stopTime - result.startTime) / static_cast<time_t>(step_->jobsets.size());
             for (auto & jobset : step_->jobsets)
                 jobset->addStep(result.startTime, charge);
         }

src/hydra-queue-runner/dispatcher.cc

@@ -46,7 +46,7 @@ void State::dispatcher()
             auto t_after_work = std::chrono::steady_clock::now();
 
             prom.dispatcher_time_spent_running.Increment(
-                std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count());
+                static_cast<double>(std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count()));
             dispatchTimeMs += std::chrono::duration_cast<std::chrono::milliseconds>(t_after_work - t_before_work).count();
 
             /* Sleep until we're woken up (either because a runnable build
@@ -63,7 +63,7 @@ void State::dispatcher()
 
             auto t_after_sleep = std::chrono::steady_clock::now();
             prom.dispatcher_time_spent_waiting.Increment(
-                std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count());
+                static_cast<double>(std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count()));
 
         } catch (std::exception & e) {
             printError("dispatcher: %s", e.what());
@@ -190,7 +190,7 @@ system_time State::doDispatch()
         }
     }
 
-    sort(runnableSorted.begin(), runnableSorted.end(),
+    std::ranges::sort(runnableSorted,
         [](const StepInfo & a, const StepInfo & b)
         {
             return
@@ -240,11 +240,11 @@ system_time State::doDispatch()
            - Then by speed factor.
 
            - Finally by load. */
-        sort(machinesSorted.begin(), machinesSorted.end(),
+        std::ranges::sort(machinesSorted,
             [](const MachineInfo & a, const MachineInfo & b) -> bool
             {
-                float ta = std::round(a.currentJobs / a.machine->speedFactorFloat);
+                float ta = std::round(static_cast<float>(a.currentJobs) / a.machine->speedFactorFloat);
-                float tb = std::round(b.currentJobs / b.machine->speedFactorFloat);
+                float tb = std::round(static_cast<float>(b.currentJobs) / b.machine->speedFactorFloat);
                 return
                     ta != tb ? ta < tb :
                     a.machine->speedFactorFloat != b.machine->speedFactorFloat ? a.machine->speedFactorFloat > b.machine->speedFactorFloat :
@@ -345,7 +345,7 @@ void State::abortUnsupported()
     auto machines2 = *machines.lock();
 
     system_time now = std::chrono::system_clock::now();
-    auto now2 = time(0);
+    auto now2 = time(nullptr);
 
     std::unordered_set<Step::ptr> aborted;
 
@@ -436,7 +436,7 @@ void Jobset::addStep(time_t startTime, time_t duration)
 
 void Jobset::pruneSteps()
 {
-    time_t now = time(0);
+    time_t now = time(nullptr);
     auto steps_(steps.lock());
     while (!steps_->empty()) {
         auto i = steps_->begin();
@@ -464,7 +464,7 @@ State::MachineReservation::~MachineReservation()
     auto prev = machine->state->currentJobs--;
     assert(prev);
     if (prev == 1)
-        machine->state->idleSince = time(0);
+        machine->state->idleSince = time(nullptr);
 
     {
         auto machineTypes_(state.machineTypes.lock());

src/hydra-queue-runner/hydra-build-result.hh

@@ -14,7 +14,7 @@ struct BuildProduct
     bool isRegular = false;
     std::optional<nix::Hash> sha256hash;
     std::optional<off_t> fileSize;
-    BuildProduct() { }
+    BuildProduct() = default;
 };
 
 struct BuildMetric

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

@@ -105,7 +105,7 @@ State::State(std::optional<std::string> metricsAddrOpt)
     : config(std::make_unique<HydraConfig>())
     , maxUnsupportedTime(config->getIntOption("max_unsupported_time", 0))
     , dbPool(config->getIntOption("max_db_connections", 128))
-    , localWorkThrottler(config->getIntOption("max_local_worker_threads", std::min(maxSupportedLocalWorkers, std::max(4u, std::thread::hardware_concurrency()) - 2)))
+    , localWorkThrottler(static_cast<ptrdiff_t>(config->getIntOption("max_local_worker_threads", std::min(maxSupportedLocalWorkers, std::max(4u, std::thread::hardware_concurrency()) - 2))))
     , maxOutputSize(config->getIntOption("max_output_size", 2ULL << 30))
     , maxLogSize(config->getIntOption("max_log_size", 64ULL << 20))
     , uploadLogsToBinaryCache(config->getBoolOption("upload_logs_to_binary_cache", false))
@@ -138,7 +138,7 @@ nix::MaintainCount<counter> State::startDbUpdate()
 {
     if (nrActiveDbUpdates > 6)
         printError("warning: %d concurrent database updates; PostgreSQL may be stalled", nrActiveDbUpdates.load());
-    return MaintainCount<counter>(nrActiveDbUpdates);
+    return {nrActiveDbUpdates};
 }
 
 
@@ -171,7 +171,7 @@ void State::parseMachines(const std::string & contents)
         for (auto & f : mandatoryFeatures)
             supportedFeatures.insert(f);
 
-        using MaxJobs = std::remove_const<decltype(nix::Machine::maxJobs)>::type;
+        using MaxJobs = std::remove_const_t<decltype(nix::Machine::maxJobs)>;
 
         auto machine = std::make_shared<::Machine>(::Machine {{
             // `storeUri`, not yet used
@@ -198,7 +198,7 @@ void State::parseMachines(const std::string & contents)
 
         machine->sshName = tokens[0];
         machine->systemTypesSet = tokenizeString<StringSet>(tokens[1], ",");
-        machine->speedFactorFloat = atof(tokens[4].c_str());
+        machine->speedFactorFloat = static_cast<float>(atof(tokens[4].c_str()));
 
         /* Re-use the State object of the previous machine with the
            same name. */
@@ -412,7 +412,7 @@ void State::finishBuildStep(pqxx::work & txn, const RemoteResult & result,
 }
 
 
-int State::createSubstitutionStep(pqxx::work & txn, time_t startTime, time_t stopTime,
+unsigned int State::createSubstitutionStep(pqxx::work & txn, time_t startTime, time_t stopTime,
     Build::ptr build, const StorePath & drvPath, const nix::Derivation drv, const std::string & outputName, const StorePath & storePath)
 {
  restart:
@@ -594,7 +594,7 @@ std::shared_ptr<PathLocks> State::acquireGlobalLock()
     createDirs(dirOf(lockPath));
 
     auto lock = std::make_shared<PathLocks>();
-    if (!lock->lockPaths(PathSet({lockPath}), "", false)) return 0;
+    if (!lock->lockPaths(PathSet({lockPath}), "", false)) return nullptr;
 
     return lock;
 }
@@ -602,10 +602,10 @@ std::shared_ptr<PathLocks> State::acquireGlobalLock()
 
 void State::dumpStatus(Connection & conn)
 {
-    time_t now = time(0);
+    time_t now = time(nullptr);
     json statusJson = {
         {"status", "up"},
-        {"time", time(0)},
+        {"time", time(nullptr)},
         {"uptime", now - startedAt},
         {"pid", getpid()},
 
@@ -620,7 +620,7 @@ void State::dumpStatus(Connection & conn)
         {"bytesReceived", bytesReceived.load()},
         {"nrBuildsRead", nrBuildsRead.load()},
         {"buildReadTimeMs", buildReadTimeMs.load()},
-        {"buildReadTimeAvgMs", nrBuildsRead == 0 ? 0.0 : (float) buildReadTimeMs / nrBuildsRead},
+        {"buildReadTimeAvgMs", nrBuildsRead == 0 ? 0.0 : (float) buildReadTimeMs / (float) nrBuildsRead},
         {"nrBuildsDone", nrBuildsDone.load()},
         {"nrStepsStarted", nrStepsStarted.load()},
         {"nrStepsDone", nrStepsDone.load()},
@@ -629,7 +629,7 @@ void State::dumpStatus(Connection & conn)
         {"nrQueueWakeups", nrQueueWakeups.load()},
         {"nrDispatcherWakeups", nrDispatcherWakeups.load()},
         {"dispatchTimeMs", dispatchTimeMs.load()},
-        {"dispatchTimeAvgMs", nrDispatcherWakeups == 0 ? 0.0 : (float) dispatchTimeMs / nrDispatcherWakeups},
+        {"dispatchTimeAvgMs", nrDispatcherWakeups == 0 ? 0.0 : (float) dispatchTimeMs / (float) nrDispatcherWakeups},
         {"nrDbConnections", dbPool.count()},
         {"nrActiveDbUpdates", nrActiveDbUpdates.load()},
     };
@@ -649,8 +649,8 @@ void State::dumpStatus(Connection & conn)
         if (nrStepsDone) {
             statusJson["totalStepTime"] = totalStepTime.load();
             statusJson["totalStepBuildTime"] = totalStepBuildTime.load();
-            statusJson["avgStepTime"] = (float) totalStepTime / nrStepsDone;
+            statusJson["avgStepTime"] = (float) totalStepTime / (float) nrStepsDone;
-            statusJson["avgStepBuildTime"] = (float) totalStepBuildTime / nrStepsDone;
+            statusJson["avgStepBuildTime"] = (float) totalStepBuildTime / (float) nrStepsDone;
         }
 
         {
@@ -677,8 +677,8 @@ void State::dumpStatus(Connection & conn)
                 if (m->state->nrStepsDone) {
                     machine["totalStepTime"] = s->totalStepTime.load();
                     machine["totalStepBuildTime"] = s->totalStepBuildTime.load();
-                    machine["avgStepTime"] = (float) s->totalStepTime / s->nrStepsDone;
+                    machine["avgStepTime"] = (float) s->totalStepTime / (float) s->nrStepsDone;
-                    machine["avgStepBuildTime"] = (float) s->totalStepBuildTime / s->nrStepsDone;
+                    machine["avgStepBuildTime"] = (float) s->totalStepBuildTime / (float) s->nrStepsDone;
                 }
                 statusJson["machines"][m->sshName] = machine;
             }
@@ -706,7 +706,7 @@ void State::dumpStatus(Connection & conn)
                 };
                 if (i.second.runnable > 0)
                     machineTypeJson["waitTime"] = i.second.waitTime.count() +
-                        i.second.runnable * (time(0) - lastDispatcherCheck);
+                        i.second.runnable * (time(nullptr) - lastDispatcherCheck);
                 if (i.second.running == 0)
                     machineTypeJson["lastActive"] = std::chrono::system_clock::to_time_t(i.second.lastActive);
             }
@@ -732,11 +732,11 @@ void State::dumpStatus(Connection & conn)
             {"narWriteCompressionTimeMs", stats.narWriteCompressionTimeMs.load()},
             {"narCompressionSavings",
              stats.narWriteBytes
-             ? 1.0 - (double) stats.narWriteCompressedBytes / stats.narWriteBytes
+             ? 1.0 - (double) stats.narWriteCompressedBytes / (double) stats.narWriteBytes
              : 0.0},
             {"narCompressionSpeed", // MiB/s
             stats.narWriteCompressionTimeMs
-            ? (double) stats.narWriteBytes / stats.narWriteCompressionTimeMs * 1000.0 / (1024.0 * 1024.0)
+            ? (double) stats.narWriteBytes / (double) stats.narWriteCompressionTimeMs * 1000.0 / (1024.0 * 1024.0)
             : 0.0},
         };
 
@@ -749,20 +749,20 @@ void State::dumpStatus(Connection & conn)
                 {"putTimeMs", s3Stats.putTimeMs.load()},
                 {"putSpeed",
                  s3Stats.putTimeMs
-                 ? (double) s3Stats.putBytes / s3Stats.putTimeMs * 1000.0 / (1024.0 * 1024.0)
+                 ? (double) s3Stats.putBytes / (double) s3Stats.putTimeMs * 1000.0 / (1024.0 * 1024.0)
                  : 0.0},
                 {"get", s3Stats.get.load()},
                 {"getBytes", s3Stats.getBytes.load()},
                 {"getTimeMs", s3Stats.getTimeMs.load()},
                 {"getSpeed",
                  s3Stats.getTimeMs
-                 ? (double) s3Stats.getBytes / s3Stats.getTimeMs * 1000.0 / (1024.0 * 1024.0)
+                 ? (double) s3Stats.getBytes / (double) s3Stats.getTimeMs * 1000.0 / (1024.0 * 1024.0)
                  : 0.0},
                 {"head", s3Stats.head.load()},
                 {"costDollarApprox",
-                        (s3Stats.get + s3Stats.head) / 10000.0 * 0.004
+                        (double) (s3Stats.get + s3Stats.head) / 10000.0 * 0.004
-                        + s3Stats.put / 1000.0 * 0.005 +
+                        + (double) s3Stats.put / 1000.0 * 0.005 +
-                        + s3Stats.getBytes / (1024.0 * 1024.0 * 1024.0) * 0.09},
+                        + (double) s3Stats.getBytes / (1024.0 * 1024.0 * 1024.0) * 0.09},
             };
         }
     }
@@ -848,7 +848,7 @@ void State::run(BuildID buildOne)
     /* Can't be bothered to shut down cleanly. Goodbye! */
     auto callback = createInterruptCallback([&]() { std::_Exit(0); });
 
-    startedAt = time(0);
+    startedAt = time(nullptr);
     this->buildOne = buildOne;
 
     auto lock = acquireGlobalLock();

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

@@ -3,6 +3,7 @@
 #include "archive.hh"
 
 #include <unordered_set>
+#include <utility>
 
 using namespace nix;
 
@@ -18,8 +19,8 @@ struct Extractor : ParseSink
     NarMemberData * curMember = nullptr;
     Path prefix;
 
-    Extractor(NarMemberDatas & members, const Path & prefix)
+    Extractor(NarMemberDatas & members, Path  prefix)
-        : members(members), prefix(prefix)
+        : members(members), prefix(std::move(prefix))
     { }
 
     void createDirectory(const Path & path) override

src/hydra-queue-runner/nar-extractor.hh

@@ -13,7 +13,7 @@ struct NarMemberData
     std::optional<nix::Hash> sha256;
 };
 
-typedef std::map<nix::Path, NarMemberData> NarMemberDatas;
+using NarMemberDatas = std::map<nix::Path, NarMemberData>;
 
 /* Read a NAR from a source and get to some info about every file
    inside the NAR. */

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

@@ -4,7 +4,8 @@
 #include "thread-pool.hh"
 
 #include <cstring>
-#include <signal.h>
+#include <utility>
+#include <csignal>
 
 using namespace nix;
 
@@ -52,7 +53,7 @@ void State::queueMonitorLoop(Connection & conn)
         auto t_after_work = std::chrono::steady_clock::now();
 
         prom.queue_monitor_time_spent_running.Increment(
-            std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count());
+            static_cast<double>(std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count()));
 
         /* Sleep until we get notification from the database about an
            event. */
@@ -79,7 +80,7 @@ void State::queueMonitorLoop(Connection & conn)
 
         auto t_after_sleep = std::chrono::steady_clock::now();
         prom.queue_monitor_time_spent_waiting.Increment(
-            std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count());
+            static_cast<double>(std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count()));
     }
 
     exit(0);
@@ -88,7 +89,7 @@ void State::queueMonitorLoop(Connection & conn)
 
 struct PreviousFailure : public std::exception {
     Step::ptr step;
-    PreviousFailure(Step::ptr step) : step(step) { }
+    PreviousFailure(Step::ptr step) : step(std::move(step)) { }
 };
 
 
@@ -117,7 +118,7 @@ bool State::getQueuedBuilds(Connection & conn,
 
         for (auto const & row : res) {
             auto builds_(builds.lock());
-            BuildID id = row["id"].as<BuildID>();
+            auto id = row["id"].as<BuildID>();
             if (buildOne && id != buildOne) continue;
             if (builds_->count(id)) continue;
 
@@ -137,7 +138,7 @@ bool State::getQueuedBuilds(Connection & conn,
 
             newIDs.push_back(id);
             newBuildsByID[id] = build;
-            newBuildsByPath.emplace(std::make_pair(build->drvPath, id));
+            newBuildsByPath.emplace(build->drvPath, id);
         }
     }
 
@@ -162,7 +163,7 @@ bool State::getQueuedBuilds(Connection & conn,
                     ("update Builds set finished = 1, buildStatus = $2, startTime = $3, stopTime = $3 where id = $1 and finished = 0",
                      build->id,
                      (int) bsAborted,
-                     time(0));
+                     time(nullptr));
                 txn.commit();
                 build->finishedInDB = true;
                 nrBuildsDone++;
@@ -176,7 +177,7 @@ bool State::getQueuedBuilds(Connection & conn,
         /* Create steps for this derivation and its dependencies. */
         try {
             step = createStep(destStore, conn, build, build->drvPath,
-                build, 0, finishedDrvs, newSteps, newRunnable);
+                build, nullptr, finishedDrvs, newSteps, newRunnable);
         } catch (PreviousFailure & ex) {
 
             /* Some step previously failed, so mark the build as
@@ -221,7 +222,7 @@ bool State::getQueuedBuilds(Connection & conn,
                      "where id = $1 and finished = 0",
                      build->id,
                      (int) (ex.step->drvPath == build->drvPath ? bsFailed : bsDepFailed),
-                     time(0));
+                     time(nullptr));
                 notifyBuildFinished(txn, build->id, {});
                 txn.commit();
                 build->finishedInDB = true;
@@ -254,7 +255,7 @@ bool State::getQueuedBuilds(Connection & conn,
             {
             auto mc = startDbUpdate();
             pqxx::work txn(conn);
-            time_t now = time(0);
+            time_t now = time(nullptr);
             if (!buildOneDone && build->id == buildOne) buildOneDone = true;
             printMsg(lvlInfo, "marking build %1% as succeeded (cached)", build->id);
             markSucceededBuild(txn, build, res, true, now, now);
@@ -355,7 +356,7 @@ void State::processQueueChange(Connection & conn)
         pqxx::work txn(conn);
         auto res = txn.exec("select id, globalPriority from Builds where finished = 0");
         for (auto const & row : res)
-            currentIds[row["id"].as<BuildID>()] = row["globalPriority"].as<BuildID>();
+            currentIds[row["id"].as<BuildID>()] = row["globalPriority"].as<int>();
     }
 
     {
@@ -438,7 +439,7 @@ Step::ptr State::createStep(ref<Store> destStore,
     Build::ptr referringBuild, Step::ptr referringStep, std::set<StorePath> & finishedDrvs,
     std::set<Step::ptr> & newSteps, std::set<Step::ptr> & newRunnable)
 {
-    if (finishedDrvs.find(drvPath) != finishedDrvs.end()) return 0;
+    if (finishedDrvs.find(drvPath) != finishedDrvs.end()) return nullptr;
 
     /* Check if the requested step already exists. If not, create a
        new step. In any case, make the step reachable from
@@ -516,7 +517,7 @@ Step::ptr State::createStep(ref<Store> destStore,
     std::map<DrvOutput, std::optional<StorePath>> paths;
     for (auto & [outputName, maybeOutputPath] : destStore->queryPartialDerivationOutputMap(drvPath, &*localStore)) {
         auto outputHash = outputHashes.at(outputName);
-        paths.insert({{outputHash, outputName}, maybeOutputPath});
+        paths.insert({{.drvHash=outputHash, .outputName=outputName}, maybeOutputPath});
     }
 
     auto missing = getMissingRemotePaths(destStore, paths);
@@ -560,7 +561,7 @@ Step::ptr State::createStep(ref<Store> destStore,
                 auto & path = *pathOpt;
 
                 try {
-                    time_t startTime = time(0);
+                    time_t startTime = time(nullptr);
 
                     if (localStore->isValidPath(path))
                         printInfo("copying output ‘%1%’ of ‘%2%’ from local store",
@@ -578,7 +579,7 @@ Step::ptr State::createStep(ref<Store> destStore,
                         StorePathSet { path },
                         NoRepair, CheckSigs, NoSubstitute);
 
-                    time_t stopTime = time(0);
+                    time_t stopTime = time(nullptr);
 
                     {
                         auto mc = startDbUpdate();
@@ -602,7 +603,7 @@ Step::ptr State::createStep(ref<Store> destStore,
     // FIXME: check whether all outputs are in the binary cache.
     if (valid) {
         finishedDrvs.insert(drvPath);
-        return 0;
+        return nullptr;
     }
 
     /* No, we need to build. */
@@ -610,7 +611,7 @@ Step::ptr State::createStep(ref<Store> destStore,
 
     /* Create steps for the dependencies. */
     for (auto & i : step->drv->inputDrvs.map) {
-        auto dep = createStep(destStore, conn, build, i.first, 0, step, finishedDrvs, newSteps, newRunnable);
+        auto dep = createStep(destStore, conn, build, i.first, nullptr, step, finishedDrvs, newSteps, newRunnable);
         if (dep) {
             auto step_(step->state.lock());
             step_->deps.insert(dep);
@@ -658,11 +659,11 @@ Jobset::ptr State::createJobset(pqxx::work & txn,
     auto res2 = txn.exec_params
         ("select s.startTime, s.stopTime from BuildSteps s join Builds b on build = id "
          "where s.startTime is not null and s.stopTime > $1 and jobset_id = $2",
-         time(0) - Jobset::schedulingWindow * 10,
+         time(nullptr) - Jobset::schedulingWindow * 10,
          jobsetID);
     for (auto const & row : res2) {
-        time_t startTime = row["startTime"].as<time_t>();
+        auto startTime = row["startTime"].as<time_t>();
-        time_t stopTime = row["stopTime"].as<time_t>();
+        auto stopTime = row["stopTime"].as<time_t>();
         jobset->addStep(startTime, stopTime - startTime);
     }
 
@@ -702,7 +703,7 @@ BuildOutput State::getBuildOutputCached(Connection & conn, nix::ref<nix::Store>
              "where finished = 1 and (buildStatus = 0 or buildStatus = 6) and path = $1",
              localStore->printStorePath(output));
         if (r.empty()) continue;
-        BuildID id = r[0][0].as<BuildID>();
+        auto id = r[0][0].as<BuildID>();
 
         printInfo("reusing build %d", id);
 

src/hydra-queue-runner/state.hh

@@ -8,6 +8,7 @@
 #include <queue>
 #include <regex>
 #include <semaphore>
+#include <utility>
 
 #include <prometheus/counter.h>
 #include <prometheus/gauge.h>
@@ -26,16 +27,16 @@
 #include "machines.hh"
 
 
-typedef unsigned int BuildID;
+using BuildID = unsigned int;
 
-typedef unsigned int JobsetID;
+using JobsetID = unsigned int;
 
-typedef std::chrono::time_point<std::chrono::system_clock> system_time;
+using system_time = std::chrono::time_point<std::chrono::system_clock>;
 
-typedef std::atomic<unsigned long> counter;
+using counter = std::atomic<unsigned long>;
 
 
-typedef enum {
+enum BuildStatus {
     bsSuccess = 0,
     bsFailed = 1,
     bsDepFailed = 2, // builds only
@@ -49,10 +50,10 @@ typedef enum {
     bsNarSizeLimitExceeded = 11,
     bsNotDeterministic = 12,
     bsBusy = 100, // not stored
-} BuildStatus;
+};
 
 
-typedef enum {
+enum StepState {
     ssPreparing = 1,
     ssConnecting = 10,
     ssSendingInputs = 20,
@@ -60,7 +61,7 @@ typedef enum {
     ssWaitingForLocalSlot = 35,
     ssReceivingOutputs = 40,
     ssPostProcessing = 50,
-} StepState;
+};
 
 
 struct RemoteResult
@@ -78,7 +79,7 @@ struct RemoteResult
     unsigned int overhead = 0;
     nix::Path logFile;
 
-    BuildStatus buildStatus() const
+    [[nodiscard]] BuildStatus buildStatus() const
     {
         return stepStatus == bsCachedFailure ? bsFailed : stepStatus;
     }
@@ -95,10 +96,10 @@ class Jobset
 {
 public:
 
-    typedef std::shared_ptr<Jobset> ptr;
+    using ptr = std::shared_ptr<Jobset>;
-    typedef std::weak_ptr<Jobset> wptr;
+    using wptr = std::weak_ptr<Jobset>;
 
-    static const time_t schedulingWindow = 24 * 60 * 60;
+    static const time_t schedulingWindow = static_cast<time_t>(24 * 60 * 60);
 
 private:
 
@@ -115,7 +116,7 @@ public:
         return (double) seconds / shares;
     }
 
-    void setShares(int shares_)
+    void setShares(unsigned int shares_)
     {
         assert(shares_ > 0);
         shares = shares_;
@@ -131,8 +132,8 @@ public:
 
 struct Build
 {
-    typedef std::shared_ptr<Build> ptr;
+    using ptr = std::shared_ptr<Build>;
-    typedef std::weak_ptr<Build> wptr;
+    using wptr = std::weak_ptr<Build>;
 
     BuildID id;
     nix::StorePath drvPath;
@@ -163,8 +164,8 @@ struct Build
 
 struct Step
 {
-    typedef std::shared_ptr<Step> ptr;
+    using ptr = std::shared_ptr<Step>;
-    typedef std::weak_ptr<Step> wptr;
+    using wptr = std::weak_ptr<Step>;
 
     nix::StorePath drvPath;
     std::unique_ptr<nix::Derivation> drv;
@@ -221,13 +222,8 @@ struct Step
 
     nix::Sync<State> state;
 
-    Step(const nix::StorePath & drvPath) : drvPath(drvPath)
+    Step(nix::StorePath  drvPath) : drvPath(std::move(drvPath))
     { }
-
-    ~Step()
-    {
-        //printMsg(lvlError, format("destroying step %1%") % drvPath);
-    }
 };
 
 
@@ -239,7 +235,7 @@ void visitDependencies(std::function<void(Step::ptr)> visitor, Step::ptr step);
 
 struct Machine : nix::Machine
 {
-    typedef std::shared_ptr<Machine> ptr;
+    using ptr = std::shared_ptr<Machine>;
 
     /* TODO Get rid of: `nix::Machine::storeUri` is normalized in a way
        we are not yet used to, but once we are, we don't need this. */
@@ -254,7 +250,7 @@ struct Machine : nix::Machine
     float speedFactorFloat = 1.0;
 
     struct State {
-        typedef std::shared_ptr<State> ptr;
+        using ptr = std::shared_ptr<State>;
         counter currentJobs{0};
         counter nrStepsDone{0};
         counter totalStepTime{0}; // total time for steps, including closure copying
@@ -358,22 +354,22 @@ private:
     bool useSubstitutes = false;
 
     /* The queued builds. */
-    typedef std::map<BuildID, Build::ptr> Builds;
+    using Builds = std::map<BuildID, Build::ptr>;
     nix::Sync<Builds> builds;
 
     /* The jobsets. */
-    typedef std::map<std::pair<std::string, std::string>, Jobset::ptr> Jobsets;
+    using Jobsets = std::map<std::pair<std::string, std::string>, Jobset::ptr>;
     nix::Sync<Jobsets> jobsets;
 
     /* All active or pending build steps (i.e. dependencies of the
        queued builds). Note that these are weak pointers. Steps are
        kept alive by being reachable from Builds or by being in
        progress. */
-    typedef std::map<nix::StorePath, Step::wptr> Steps;
+    using Steps = std::map<nix::StorePath, Step::wptr>;
     nix::Sync<Steps> steps;
 
     /* Build steps that have no unbuilt dependencies. */
-    typedef std::list<Step::wptr> Runnable;
+    using Runnable = std::list<Step::wptr>;
     nix::Sync<Runnable> runnable;
 
     /* CV for waking up the dispatcher. */
@@ -385,7 +381,7 @@ private:
 
     /* The build machines. */
     std::mutex machinesReadyLock;
-    typedef std::map<std::string, Machine::ptr> Machines;
+    using Machines = std::map<std::string, Machine::ptr>;
     nix::Sync<Machines> machines; // FIXME: use atomic_shared_ptr
 
     /* Throttler for CPU-bound local work. */
@@ -431,7 +427,7 @@ private:
 
     struct MachineReservation
     {
-        typedef std::shared_ptr<MachineReservation> ptr;
+        using ptr = std::shared_ptr<MachineReservation>;
         State & state;
         Step::ptr step;
         Machine::ptr machine;
@@ -534,7 +530,7 @@ private:
     void finishBuildStep(pqxx::work & txn, const RemoteResult & result, BuildID buildId, unsigned int stepNr,
         const std::string & machine);
 
-    int createSubstitutionStep(pqxx::work & txn, time_t startTime, time_t stopTime,
+    unsigned int createSubstitutionStep(pqxx::work & txn, time_t startTime, time_t stopTime,
         Build::ptr build, const nix::StorePath & drvPath, const nix::Derivation drv, const std::string & outputName, const nix::StorePath & storePath);
 
     void updateBuild(pqxx::work & txn, Build::ptr build, BuildStatus status);