queue runner: fix nullptr deref on build exception after releasing a machine reservation

(cherry picked from commit f23ec71227911891807706b6b978836e4d80edde)

flake.lock

@@ -1,5 +1,26 @@
 {
   "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "nix-eval-jobs",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1722555600,
+        "narHash": "sha256-XOQkdLafnb/p9ij77byFQjDf5m5QYl9b2REiVClC+x4=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "8471fe90ad337a8074e957b69ca4d0089218391d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
     "libgit2": {
       "flake": false,
       "locked": {
@@ -46,6 +67,30 @@
         "type": "github"
       }
     },
+    "nix-eval-jobs": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nix-github-actions": [],
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "treefmt-nix": "treefmt-nix"
+      },
+      "locked": {
+        "lastModified": 1733814344,
+        "narHash": "sha256-3wwtKpS5tUBdjaGeSia7CotonbiRB6K5Kp0dsUt3nzU=",
+        "owner": "nix-community",
+        "repo": "nix-eval-jobs",
+        "rev": "889ea1406736b53cf165b6c28398aae3969418d1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "ref": "release-2.24",
+        "repo": "nix-eval-jobs",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1726688310,
@@ -66,8 +111,30 @@
       "inputs": {
         "libgit2": "libgit2",
         "nix": "nix",
+        "nix-eval-jobs": "nix-eval-jobs",
         "nixpkgs": "nixpkgs"
       }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nix-eval-jobs",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1723303070,
+        "narHash": "sha256-krGNVA30yptyRonohQ+i9cnK+CfCpedg6z3qzqVJcTs=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "14c092e0326de759e16b37535161b3cb9770cea3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -8,6 +8,9 @@
   inputs.nix.inputs.nixpkgs.follows = "nixpkgs";
   inputs.nix.inputs.libgit2.follows = "libgit2";
 
+  inputs.nix-eval-jobs.url = "github:nix-community/nix-eval-jobs/release-2.24";
+  inputs.nix-eval-jobs.inputs.nixpkgs.follows = "nixpkgs";
+
   # hide nix dev tooling from our lock file
   inputs.nix.inputs.flake-parts.follows = "";
   inputs.nix.inputs.git-hooks-nix.follows = "";
@@ -15,7 +18,10 @@
   inputs.nix.inputs.nixpkgs-23-11.follows = "";
   inputs.nix.inputs.flake-compat.follows = "";
 
-  outputs = { self, nixpkgs, nix, ... }:
+  # hide nix-eval-jobs dev tooling from our lock file
+  inputs.nix-eval-jobs.inputs.nix-github-actions.follows = "";
+
+  outputs = { self, nixpkgs, nix, nix-eval-jobs, ... }:
     let
       systems = [ "x86_64-linux" "aarch64-linux" ];
       forEachSystem = nixpkgs.lib.genAttrs systems;
@@ -26,6 +32,7 @@
       overlays.default = final: prev: {
         hydra = final.callPackage ./package.nix {
           inherit (nixpkgs.lib) fileset;
+          nix-eval-jobs = nix-eval-jobs.packages.${final.system}.default;
           rawSrc = self;
           nix-perl-bindings = final.nixComponents.nix-perl-bindings;
         };
@@ -69,6 +76,7 @@
       packages = forEachSystem (system: {
         hydra = nixpkgs.legacyPackages.${system}.callPackage ./package.nix {
           inherit (nixpkgs.lib) fileset;
+          nix-eval-jobs = nix-eval-jobs.packages.${system}.default;
           rawSrc = self;
           nix = nix.packages.${system}.nix;
           nix-perl-bindings = nix.hydraJobs.perlBindings.${system};

package.nix

@@ -50,6 +50,7 @@
 , xz
 , gnutar
 , gnused
+, nix-eval-jobs
 
 , rpm
 , dpkg
@@ -89,6 +90,7 @@ let
         DateTime
         DBDPg
         DBDSQLite
+        DBIxClassHelpers
         DigestSHA1
         EmailMIME
         EmailSender
@@ -190,6 +192,7 @@ stdenv.mkDerivation (finalAttrs: {
     openldap
     postgresql_13
     pixz
+    nix-eval-jobs
   ];
 
   checkInputs = [
@@ -218,6 +221,7 @@ stdenv.mkDerivation (finalAttrs: {
       darcs
       gnused
       breezy
+      nix-eval-jobs
     ] ++ lib.optionals stdenv.isLinux [ rpm dpkg cdrkit ]
   );
 
@@ -232,7 +236,7 @@ stdenv.mkDerivation (finalAttrs: {
   shellHook = ''
     pushd $(git rev-parse --show-toplevel) >/dev/null
 
-    PATH=$(pwd)/src/hydra-evaluator:$(pwd)/src/script:$(pwd)/src/hydra-eval-jobs:$(pwd)/src/hydra-queue-runner:$PATH
+    PATH=$(pwd)/src/hydra-evaluator:$(pwd)/src/script:$(pwd)/src/hydra-queue-runner:$PATH
     PERL5LIB=$(pwd)/src/lib:$PERL5LIB
     export HYDRA_HOME="$(pwd)/src/"
     mkdir -p .hydra-data
@@ -263,7 +267,8 @@ stdenv.mkDerivation (finalAttrs: {
             --prefix PATH ':' $out/bin:$hydraPath \
             --set HYDRA_RELEASE ${version} \
             --set HYDRA_HOME $out/libexec/hydra \
-            --set NIX_RELEASE ${nix.name or "unknown"}
+            --set NIX_RELEASE ${nix.name or "unknown"} \
+            --set NIX_EVAL_JOBS_RELEASE ${nix-eval-jobs.name or "unknown"}
     done
   '';
 

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

@@ -1,587 +0,0 @@
-#include <iostream>
-#include <thread>
-#include <optional>
-#include <unordered_map>
-
-#include "shared.hh"
-#include "store-api.hh"
-#include "eval.hh"
-#include "eval-gc.hh"
-#include "eval-inline.hh"
-#include "eval-settings.hh"
-#include "signals.hh"
-#include "terminal.hh"
-#include "util.hh"
-#include "get-drvs.hh"
-#include "globals.hh"
-#include "common-eval-args.hh"
-#include "flake/flakeref.hh"
-#include "flake/flake.hh"
-#include "attr-path.hh"
-#include "derivations.hh"
-#include "local-fs-store.hh"
-
-#include "hydra-config.hh"
-
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <sys/resource.h>
-
-#include <nlohmann/json.hpp>
-
-void check_pid_status_nonblocking(pid_t check_pid)
-{
-    // Only check 'initialized' and known PID's
-    if (check_pid <= 0) { return; }
-
-    int wstatus = 0;
-    pid_t pid = waitpid(check_pid, &wstatus, WNOHANG);
-    // -1 = failure, WNOHANG: 0 = no change
-    if (pid <= 0) { return; }
-
-    std::cerr << "child process (" << pid << ") ";
-
-    if (WIFEXITED(wstatus)) {
-        std::cerr << "exited with status=" << WEXITSTATUS(wstatus) << std::endl;
-    } else if (WIFSIGNALED(wstatus)) {
-        std::cerr << "killed by signal=" << WTERMSIG(wstatus) << std::endl;
-    } else if (WIFSTOPPED(wstatus)) {
-        std::cerr << "stopped by signal=" << WSTOPSIG(wstatus) << std::endl;
-    } else if (WIFCONTINUED(wstatus)) {
-        std::cerr << "continued" << std::endl;
-    }
-}
-
-using namespace nix;
-
-static Path gcRootsDir;
-static size_t maxMemorySize;
-
-struct MyArgs : MixEvalArgs, MixCommonArgs, RootArgs
-{
-    Path releaseExpr;
-    bool flake = false;
-    bool dryRun = false;
-
-    MyArgs() : MixCommonArgs("hydra-eval-jobs")
-    {
-        addFlag({
-            .longName = "gc-roots-dir",
-            .description = "garbage collector roots directory",
-            .labels = {"path"},
-            .handler = {&gcRootsDir}
-        });
-
-        addFlag({
-            .longName = "dry-run",
-            .description = "don't create store derivations",
-            .handler = {&dryRun, true}
-        });
-
-        addFlag({
-            .longName = "flake",
-            .description = "build a flake",
-            .handler = {&flake, true}
-        });
-
-        expectArg("expr", &releaseExpr);
-    }
-};
-
-static MyArgs myArgs;
-
-static std::string queryMetaStrings(EvalState & state, PackageInfo & drv, const std::string & name, const std::string & subAttribute)
-{
-    Strings res;
-    std::function<void(Value & v)> rec;
-
-    rec = [&](Value & v) {
-        state.forceValue(v, noPos);
-        if (v.type() == nString)
-            res.emplace_back(v.string_view());
-        else if (v.isList())
-            for (unsigned int n = 0; n < v.listSize(); ++n)
-                rec(*v.listElems()[n]);
-        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, a->pos, "while evaluating meta attributes")));
-        }
-    };
-
-    Value * v = drv.queryMeta(name);
-    if (v) rec(*v);
-
-    return concatStringsSep(", ", res);
-}
-
-static void worker(
-    EvalState & state,
-    Bindings & autoArgs,
-    AutoCloseFD & to,
-    AutoCloseFD & from)
-{
-    Value vTop;
-
-    if (myArgs.flake) {
-        using namespace flake;
-
-        auto [flakeRef, fragment, outputSpec] = parseFlakeRefWithFragmentAndExtendedOutputsSpec(fetchSettings, myArgs.releaseExpr, absPath("."));
-
-        auto vFlake = state.allocValue();
-
-        auto lockedFlake = lockFlake(
-                flakeSettings,
-                state,
-                flakeRef,
-            LockFlags {
-                .updateLockFile = false,
-                .useRegistries = false,
-                .allowUnlocked = false,
-            });
-
-        callFlake(state, lockedFlake, *vFlake);
-
-        auto vOutputs = vFlake->attrs()->get(state.symbols.create("outputs"))->value;
-        state.forceValue(*vOutputs, noPos);
-
-        auto aHydraJobs = vOutputs->attrs()->get(state.symbols.create("hydraJobs"));
-        if (!aHydraJobs)
-            aHydraJobs = vOutputs->attrs()->get(state.symbols.create("checks"));
-        if (!aHydraJobs)
-            throw Error("flake '%s' does not provide any Hydra jobs or checks", flakeRef);
-
-        vTop = *aHydraJobs->value;
-
-    } else {
-        state.evalFile(lookupFileArg(state, myArgs.releaseExpr), vTop);
-    }
-
-    auto vRoot = state.allocValue();
-    state.autoCallFunction(autoArgs, vTop, *vRoot);
-
-    while (true) {
-        /* Wait for the master to send us a job name. */
-        writeLine(to.get(), "next");
-
-        auto s = readLine(from.get());
-        if (s == "exit") break;
-        if (!hasPrefix(s, "do ")) abort();
-        std::string attrPath(s, 3);
-
-        debug("worker process %d at '%s'", getpid(), attrPath);
-
-        /* Evaluate it and send info back to the master. */
-        nlohmann::json reply;
-
-        try {
-            auto vTmp = findAlongAttrPath(state, attrPath, autoArgs, *vRoot).first;
-
-            auto v = state.allocValue();
-            state.autoCallFunction(autoArgs, *vTmp, *v);
-
-            if (auto drv = getDerivation(state, *v, false)) {
-
-                // CA derivations do not have static output paths, so we
-                // have to defensively not query output paths in case we
-                // encounter one.
-                PackageInfo::Outputs outputs = drv->queryOutputs(
-                    !experimentalFeatureSettings.isEnabled(Xp::CaDerivations));
-
-                if (drv->querySystem() == "unknown")
-                    state.error<EvalError>("derivation must have a 'system' attribute").debugThrow();
-
-                auto drvPath = state.store->printStorePath(drv->requireDrvPath());
-
-                nlohmann::json job;
-
-                job["nixName"] = drv->queryName();
-                job["system"] =drv->querySystem();
-                job["drvPath"] = drvPath;
-                job["description"] = drv->queryMetaString("description");
-                job["license"] = queryMetaStrings(state, *drv, "license", "shortName");
-                job["homepage"] = drv->queryMetaString("homepage");
-                job["maintainers"] = queryMetaStrings(state, *drv, "maintainers", "email");
-                job["schedulingPriority"] = drv->queryMetaInt("schedulingPriority", 100);
-                job["timeout"] = drv->queryMetaInt("timeout", 36000);
-                job["maxSilent"] = drv->queryMetaInt("maxSilent", 7200);
-                job["isChannel"] = drv->queryMetaBool("isHydraChannel", false);
-
-                /* 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, "while evaluating the `_hydraAggregate` attribute")) {
-                    auto a = v->attrs()->get(state.symbols.create("constituents"));
-                    if (!a)
-                        state.error<EvalError>("derivation must have a ‘constituents’ attribute").debugThrow();
-
-                    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(b.drvPath->to_string(*state.store));
-                            },
-                            [&](const NixStringContextElem::Opaque & o) {
-                            },
-                            [&](const NixStringContextElem::DrvDeep & d) {
-                            },
-                        }, c.raw);
-
-                    state.forceList(*a->value, a->pos, "while evaluating the `constituents` attribute");
-                    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(v->string_view());
-                    }
-                }
-
-                /* Register the derivation as a GC root.  !!! This
-                   registers roots for jobs that we may have already
-                   done. */
-                auto localStore = state.store.dynamic_pointer_cast<LocalFSStore>();
-                if (gcRootsDir != "" && localStore) {
-                    Path root = gcRootsDir + "/" + std::string(baseNameOf(drvPath));
-                    if (!pathExists(root))
-                        localStore->addPermRoot(localStore->parseStorePath(drvPath), root);
-                }
-
-                nlohmann::json out;
-                for (auto & [outputName, optOutputPath] : outputs) {
-                    if (optOutputPath) {
-                        out[outputName] = state.store->printStorePath(*optOutputPath);
-                    } else {
-                        // See the `queryOutputs` call above; we should
-                        // not encounter missing output paths otherwise.
-                        assert(experimentalFeatureSettings.isEnabled(Xp::CaDerivations));
-                        out[outputName] = nullptr;
-                    }
-                }
-                job["outputs"] = std::move(out);
-                reply["job"] = std::move(job);
-            }
-
-            else if (v->type() == nAttrs) {
-                auto attrs = nlohmann::json::array();
-                StringSet ss;
-                for (auto & i : v->attrs()->lexicographicOrder(state.symbols)) {
-                    std::string name(state.symbols[i->name]);
-                    if (name.find(' ') != std::string::npos) {
-                        printError("skipping job with illegal name '%s'", name);
-                        continue;
-                    }
-                    attrs.push_back(name);
-                }
-                reply["attrs"] = std::move(attrs);
-            }
-
-            else if (v->type() == nNull)
-                ;
-
-            else state.error<TypeError>("attribute '%s' is %s, which is not supported", attrPath, showType(*v)).debugThrow();
-
-        } catch (EvalError & e) {
-            auto msg = e.msg();
-            // Transmits the error we got from the previous evaluation
-            // in the JSON output.
-            reply["error"] = filterANSIEscapes(msg, true);
-            // Don't forget to print it into the STDERR log, this is
-            // what's shown in the Hydra UI.
-            printError(msg);
-        }
-
-        writeLine(to.get(), reply.dump());
-
-        /* If our RSS exceeds the maximum, exit. The master will
-           start a new process. */
-        struct rusage r;
-        getrusage(RUSAGE_SELF, &r);
-        if ((size_t) r.ru_maxrss > maxMemorySize * 1024) break;
-    }
-
-    writeLine(to.get(), "restart");
-}
-
-int main(int argc, char * * argv)
-{
-    /* Prevent undeclared dependencies in the evaluation via
-       $NIX_PATH. */
-    unsetenv("NIX_PATH");
-
-    return handleExceptions(argv[0], [&]() {
-
-        auto config = std::make_unique<HydraConfig>();
-
-        auto nrWorkers = config->getIntOption("evaluator_workers", 1);
-        maxMemorySize = config->getIntOption("evaluator_max_memory_size", 4096);
-
-        initNix();
-        initGC();
-
-        myArgs.parseCmdline(argvToStrings(argc, argv));
-
-        auto pureEval = config->getBoolOption("evaluator_pure_eval", myArgs.flake);
-
-        /* FIXME: The build hook in conjunction with import-from-derivation is causing "unexpected EOF" during eval */
-        settings.builders = "";
-
-        /* Prevent access to paths outside of the Nix search path and
-           to the environment. */
-        evalSettings.restrictEval = true;
-
-        /* When building a flake, use pure evaluation (no access to
-           'getEnv', 'currentSystem' etc. */
-        evalSettings.pureEval = pureEval;
-
-        if (myArgs.dryRun) settings.readOnlyMode = true;
-
-        if (myArgs.releaseExpr == "") throw UsageError("no expression specified");
-
-        if (gcRootsDir == "") printMsg(lvlError, "warning: `--gc-roots-dir' not specified");
-
-        struct State
-        {
-            std::set<std::string> todo{""};
-            std::set<std::string> active;
-            nlohmann::json jobs;
-            std::exception_ptr exc;
-        };
-
-        std::condition_variable wakeup;
-
-        Sync<State> state_;
-
-        /* Start a handler thread per worker process. */
-        auto handler = [&]()
-        {
-            pid_t pid = -1;
-            try {
-                AutoCloseFD from, to;
-
-                while (true) {
-
-                    /* Start a new worker process if necessary. */
-                    if (pid == -1) {
-                        Pipe toPipe, fromPipe;
-                        toPipe.create();
-                        fromPipe.create();
-                        pid = startProcess(
-                            [&,
-                             to{std::make_shared<AutoCloseFD>(std::move(fromPipe.writeSide))},
-                             from{std::make_shared<AutoCloseFD>(std::move(toPipe.readSide))}
-                            ]()
-                            {
-                                try {
-                                    auto evalStore = myArgs.evalStoreUrl
-                                             ? openStore(*myArgs.evalStoreUrl)
-                                             : openStore();
-                                    EvalState state(myArgs.lookupPath,
-                                            evalStore, fetchSettings, evalSettings);
-                                    Bindings & autoArgs = *myArgs.getAutoArgs(state);
-                                    worker(state, autoArgs, *to, *from);
-                                } catch (Error & e) {
-                                    nlohmann::json err;
-                                    auto msg = e.msg();
-                                    err["error"] = filterANSIEscapes(msg, true);
-                                    printError(msg);
-                                    writeLine(to->get(), err.dump());
-                                    // Don't forget to print it into the STDERR log, this is
-                                    // what's shown in the Hydra UI.
-                                    writeLine(to->get(), "restart");
-                                }
-                            },
-                            ProcessOptions { .allowVfork = false });
-                        from = std::move(fromPipe.readSide);
-                        to = std::move(toPipe.writeSide);
-                        debug("created worker process %d", pid);
-                    }
-
-                    /* Check whether the existing worker process is still there. */
-                    auto s = readLine(from.get());
-                    if (s == "restart") {
-                        pid = -1;
-                        continue;
-                    } else if (s != "next") {
-                        auto json = nlohmann::json::parse(s);
-                        throw Error("worker error: %s", (std::string) json["error"]);
-                    }
-
-                    /* Wait for a job name to become available. */
-                    std::string attrPath;
-
-                    while (true) {
-                        checkInterrupt();
-                        auto state(state_.lock());
-                        if ((state->todo.empty() && state->active.empty()) || state->exc) {
-                            writeLine(to.get(), "exit");
-                            return;
-                        }
-                        if (!state->todo.empty()) {
-                            attrPath = *state->todo.begin();
-                            state->todo.erase(state->todo.begin());
-                            state->active.insert(attrPath);
-                            break;
-                        } else
-                            state.wait(wakeup);
-                    }
-
-                    /* Tell the worker to evaluate it. */
-                    writeLine(to.get(), "do " + attrPath);
-
-                    /* Wait for the response. */
-                    auto response = nlohmann::json::parse(readLine(from.get()));
-
-                    /* Handle the response. */
-                    StringSet newAttrs;
-
-                    if (response.find("job") != response.end()) {
-                        auto state(state_.lock());
-                        state->jobs[attrPath] = response["job"];
-                    }
-
-                    if (response.find("attrs") != response.end()) {
-                        for (auto & i : response["attrs"]) {
-                            std::string path = i;
-                            if (path.find(".") != std::string::npos){
-                                path = "\"" + path  + "\"";
-                            }
-                            auto s = (attrPath.empty() ? "" : attrPath + ".") + (std::string) path;
-                            newAttrs.insert(s);
-                        }
-                    }
-
-                    if (response.find("error") != response.end()) {
-                        auto state(state_.lock());
-                        state->jobs[attrPath]["error"] = response["error"];
-                    }
-
-                    /* Add newly discovered job names to the queue. */
-                    {
-                        auto state(state_.lock());
-                        state->active.erase(attrPath);
-                        for (auto & s : newAttrs)
-                            state->todo.insert(s);
-                        wakeup.notify_all();
-                    }
-                }
-            } catch (...) {
-                check_pid_status_nonblocking(pid);
-                auto state(state_.lock());
-                state->exc = std::current_exception();
-                wakeup.notify_all();
-            }
-        };
-
-        std::vector<std::thread> threads;
-        for (size_t i = 0; i < nrWorkers; i++)
-            threads.emplace_back(std::thread(handler));
-
-        for (auto & thread : threads)
-            thread.join();
-
-        auto state(state_.lock());
-
-        if (state->exc)
-            std::rethrow_exception(state->exc);
-
-        /* For aggregate jobs that have named consistuents
-           (i.e. constituents that are a job name rather than a
-           derivation), look up the referenced job and add it to the
-           dependencies of the aggregate derivation. */
-        auto store = openStore();
-
-        for (auto i = state->jobs.begin(); i != state->jobs.end(); ++i) {
-            auto jobName = i.key();
-            auto & job = i.value();
-
-            auto named = job.find("namedConstituents");
-            if (named == job.end()) continue;
-
-            std::unordered_map<std::string, std::string> brokenJobs;
-            auto getNonBrokenJobOrRecordError = [&brokenJobs, &jobName, &state](
-                    const std::string & childJobName) -> std::optional<nlohmann::json> {
-                auto childJob = state->jobs.find(childJobName);
-                if (childJob == state->jobs.end()) {
-                    printError("aggregate job '%s' references non-existent job '%s'", jobName, childJobName);
-                    brokenJobs[childJobName] = "does not exist";
-                    return std::nullopt;
-                }
-                if (childJob->find("error") != childJob->end()) {
-                    std::string error = (*childJob)["error"];
-                    printError("aggregate job '%s' references broken job '%s': %s", jobName, childJobName, error);
-                    brokenJobs[childJobName] = error;
-                    return std::nullopt;
-                }
-                return *childJob;
-            };
-
-            if (myArgs.dryRun) {
-                for (std::string jobName2 : *named) {
-                    auto job2 = getNonBrokenJobOrRecordError(jobName2);
-                    if (!job2) {
-                        continue;
-                    }
-                    std::string drvPath2 = (*job2)["drvPath"];
-                    job["constituents"].push_back(drvPath2);
-                }
-            } else {
-                auto drvPath = store->parseStorePath((std::string) job["drvPath"]);
-                auto drv = store->readDerivation(drvPath);
-
-                for (std::string jobName2 : *named) {
-                    auto job2 = getNonBrokenJobOrRecordError(jobName2);
-                    if (!job2) {
-                        continue;
-                    }
-                    auto drvPath2 = store->parseStorePath((std::string) (*job2)["drvPath"]);
-                    auto drv2 = store->readDerivation(drvPath2);
-                    job["constituents"].push_back(store->printStorePath(drvPath2));
-                    drv.inputDrvs.map[drvPath2].value = {drv2.outputs.begin()->first};
-                }
-
-                if (brokenJobs.empty()) {
-                    std::string drvName(drvPath.name());
-                    assert(hasSuffix(drvName, drvExtension));
-                    drvName.resize(drvName.size() - drvExtension.size());
-
-                    auto hashModulo = hashDerivationModulo(*store, drv, true);
-                    if (hashModulo.kind != DrvHash::Kind::Regular) continue;
-                    auto h = hashModulo.hashes.find("out");
-                    if (h == hashModulo.hashes.end()) continue;
-                    auto outPath = store->makeOutputPath("out", h->second, drvName);
-                    drv.env["out"] = store->printStorePath(outPath);
-                    drv.outputs.insert_or_assign("out", DerivationOutput::InputAddressed { .path = outPath });
-                    auto newDrvPath = store->printStorePath(writeDerivation(*store, drv));
-
-                    debug("rewrote aggregate derivation %s -> %s", store->printStorePath(drvPath), newDrvPath);
-
-                    job["drvPath"] = newDrvPath;
-                    job["outputs"]["out"] = store->printStorePath(outPath);
-                }
-            }
-
-            job.erase("namedConstituents");
-
-            /* Register the derivation as a GC root.  !!! This
-                registers roots for jobs that we may have already
-                done. */
-            auto localStore = store.dynamic_pointer_cast<LocalFSStore>();
-            if (gcRootsDir != "" && localStore) {
-                auto drvPath = job["drvPath"].get<std::string>();
-                Path root = gcRootsDir + "/" + std::string(baseNameOf(drvPath));
-                if (!pathExists(root))
-                    localStore->addPermRoot(localStore->parseStorePath(drvPath), root);
-            }
-
-            if (!brokenJobs.empty()) {
-                std::stringstream ss;
-                for (const auto& [jobName, error] : brokenJobs) {
-                    ss << jobName << ": " << error << "\n";
-                }
-                job["error"] = ss.str();
-            }
-        }
-
-        std::cout << state->jobs.dump(2) << "\n";
-    });
-}

src/hydra-eval-jobs/meson.build

@@ -1,8 +0,0 @@
-hydra_eval_jobs = executable('hydra-eval-jobs',
-  'hydra-eval-jobs.cc',
-  dependencies: [
-    libhydra_dep,
-    nix_dep,
-  ],
-  install: true,
-)

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

@@ -412,8 +412,19 @@ void RemoteResult::updateWithBuildResult(const nix::BuildResult & buildResult)
 
 }
 
+/* Utility guard object to auto-release a semaphore on destruction. */
+template <typename T>
+class SemaphoreReleaser {
+public:
+    SemaphoreReleaser(T* s) : sem(s) {}
+    ~SemaphoreReleaser() { sem->release(); }
+
+private:
+    T* sem;
+};
 
 void State::buildRemote(ref<Store> destStore,
+    MachineReservation::ptr & reservation,
     ::Machine::ptr machine, Step::ptr step,
     const ServeProto::BuildOptions & buildOptions,
     RemoteResult & result, std::shared_ptr<ActiveStep> activeStep,
@@ -551,6 +562,24 @@ void State::buildRemote(ref<Store> destStore,
             result.logFile = "";
         }
 
+        /* Throttle CPU-bound work. Opportunistically skip updating the current
+         * step, since this requires a DB roundtrip. */
+        if (!localWorkThrottler.try_acquire()) {
+            MaintainCount<counter> mc(nrStepsWaitingForDownloadSlot);
+            updateStep(ssWaitingForLocalSlot);
+            localWorkThrottler.acquire();
+        }
+        SemaphoreReleaser releaser(&localWorkThrottler);
+
+        /* Once we've started copying outputs, release the machine reservation
+         * so further builds can happen. We do not release the machine earlier
+         * to avoid situations where the queue runner is bottlenecked on
+         * 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;
+        wakeDispatcher();
+
         StorePathSet outputs;
         for (auto & [_, realisation] : buildResult.builtOutputs)
             outputs.insert(realisation.outPath);

src/hydra-queue-runner/builder.cc

@@ -37,19 +37,22 @@ void State::builder(MachineReservation::ptr reservation)
 
         try {
             auto destStore = getDestStore();
+            // Might release the reservation.
             res = doBuildStep(destStore, reservation, activeStep);
         } catch (std::exception & e) {
             printMsg(lvlError, "uncaught exception building ‘%s’ on ‘%s’: %s",
-                localStore->printStorePath(reservation->step->drvPath),
-                reservation->machine->sshName,
+                localStore->printStorePath(activeStep->step->drvPath),
+                reservation ? reservation->machine->sshName : std::string("(no machine)"),
                 e.what());
         }
     }
 
-    /* Release the machine and wake up the dispatcher. */
-    assert(reservation.unique());
-    reservation = 0;
-    wakeDispatcher();
+    /* If the machine hasn't been released yet, release and wake up the dispatcher. */
+    if (reservation) {
+        assert(reservation.unique());
+        reservation = 0;
+        wakeDispatcher();
+    }
 
     /* If there was a temporary failure, retry the step after an
        exponentially increasing interval. */
@@ -72,11 +75,11 @@ void State::builder(MachineReservation::ptr reservation)
 
 
 State::StepResult State::doBuildStep(nix::ref<Store> destStore,
-    MachineReservation::ptr reservation,
+    MachineReservation::ptr & reservation,
     std::shared_ptr<ActiveStep> activeStep)
 {
-    auto & step(reservation->step);
-    auto & machine(reservation->machine);
+    auto step(reservation->step);
+    auto machine(reservation->machine);
 
     {
         auto step_(step->state.lock());
@@ -211,7 +214,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
 
         try {
             /* FIXME: referring builds may have conflicting timeouts. */
-            buildRemote(destStore, machine, step, buildOptions, result, activeStep, updateStep, narMembers);
+            buildRemote(destStore, reservation, machine, step, buildOptions, result, activeStep, updateStep, narMembers);
         } catch (Error & e) {
             if (activeStep->state_.lock()->cancelled) {
                 printInfo("marking step %d of build %d as cancelled", stepNr, buildId);

src/hydra-queue-runner/dispatcher.cc

@@ -40,13 +40,15 @@ void State::dispatcher()
             printMsg(lvlDebug, "dispatcher woken up");
             nrDispatcherWakeups++;
 
-            auto now1 = std::chrono::steady_clock::now();
+            auto t_before_work = std::chrono::steady_clock::now();
 
             auto sleepUntil = doDispatch();
 
-            auto now2 = std::chrono::steady_clock::now();
+            auto t_after_work = std::chrono::steady_clock::now();
 
-            dispatchTimeMs += std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();
+            prom.dispatcher_time_spent_running.Increment(
+                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
                is added, or because a build finishes). */
@@ -60,6 +62,10 @@ void State::dispatcher()
                 *dispatcherWakeup_ = false;
             }
 
+            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());
+
         } catch (std::exception & e) {
             printError("dispatcher: %s", e.what());
             sleep(1);

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

@@ -70,10 +70,31 @@ State::PromMetrics::PromMetrics()
             .Register(*registry)
             .Add({})
     )
-    , queue_max_id(
-        prometheus::BuildGauge()
-            .Name("hydraqueuerunner_queue_max_build_id_info")
-            .Help("Maximum build record ID in the queue")
+    , dispatcher_time_spent_running(
+        prometheus::BuildCounter()
+            .Name("hydraqueuerunner_dispatcher_time_spent_running")
+            .Help("Time (in micros) spent running the dispatcher")
+            .Register(*registry)
+            .Add({})
+    )
+    , dispatcher_time_spent_waiting(
+        prometheus::BuildCounter()
+            .Name("hydraqueuerunner_dispatcher_time_spent_waiting")
+            .Help("Time (in micros) spent waiting for the dispatcher to obtain work")
+            .Register(*registry)
+            .Add({})
+    )
+    , queue_monitor_time_spent_running(
+        prometheus::BuildCounter()
+            .Name("hydraqueuerunner_queue_monitor_time_spent_running")
+            .Help("Time (in micros) spent running the queue monitor")
+            .Register(*registry)
+            .Add({})
+    )
+    , queue_monitor_time_spent_waiting(
+        prometheus::BuildCounter()
+            .Name("hydraqueuerunner_queue_monitor_time_spent_waiting")
+            .Help("Time (in micros) spent waiting for the queue monitor to obtain work")
             .Register(*registry)
             .Add({})
     )
@@ -85,6 +106,7 @@ 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)))
     , 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))
@@ -590,6 +612,7 @@ void State::dumpStatus(Connection & conn)
         {"nrActiveSteps", activeSteps_.lock()->size()},
         {"nrStepsBuilding", nrStepsBuilding.load()},
         {"nrStepsCopyingTo", nrStepsCopyingTo.load()},
+        {"nrStepsWaitingForDownloadSlot", nrStepsWaitingForDownloadSlot.load()},
         {"nrStepsCopyingFrom", nrStepsCopyingFrom.load()},
         {"nrStepsWaiting", nrStepsWaiting.load()},
         {"nrUnsupportedSteps", nrUnsupportedSteps.load()},

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

@@ -1,6 +1,7 @@
 #include "state.hh"
 #include "hydra-build-result.hh"
 #include "globals.hh"
+#include "thread-pool.hh"
 
 #include <cstring>
 
@@ -37,16 +38,21 @@ void State::queueMonitorLoop(Connection & conn)
 
     auto destStore = getDestStore();
 
-    unsigned int lastBuildId = 0;
-
     bool quit = false;
     while (!quit) {
+        auto t_before_work = std::chrono::steady_clock::now();
+
         localStore->clearPathInfoCache();
 
-        bool done = getQueuedBuilds(conn, destStore, lastBuildId);
+        bool done = getQueuedBuilds(conn, destStore);
 
         if (buildOne && buildOneDone) quit = true;
 
+        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());
+
         /* Sleep until we get notification from the database about an
            event. */
         if (done && !quit) {
@@ -56,12 +62,10 @@ void State::queueMonitorLoop(Connection & conn)
             conn.get_notifs();
 
         if (auto lowestId = buildsAdded.get()) {
-            lastBuildId = std::min(lastBuildId, static_cast<unsigned>(std::stoul(*lowestId) - 1));
             printMsg(lvlTalkative, "got notification: new builds added to the queue");
         }
         if (buildsRestarted.get()) {
             printMsg(lvlTalkative, "got notification: builds restarted");
-            lastBuildId = 0; // check all builds
         }
         if (buildsCancelled.get() || buildsDeleted.get() || buildsBumped.get()) {
             printMsg(lvlTalkative, "got notification: builds cancelled or bumped");
@@ -71,6 +75,10 @@ void State::queueMonitorLoop(Connection & conn)
             printMsg(lvlTalkative, "got notification: jobset shares changed");
             processJobsetSharesChange(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());
     }
 
     exit(0);
@@ -84,20 +92,18 @@ struct PreviousFailure : public std::exception {
 
 
 bool State::getQueuedBuilds(Connection & conn,
-    ref<Store> destStore, unsigned int & lastBuildId)
+    ref<Store> destStore)
 {
     prom.queue_checks_started.Increment();
 
-    printInfo("checking the queue for builds > %d...", lastBuildId);
+    printInfo("checking the queue for builds...");
 
     /* Grab the queued builds from the database, but don't process
        them yet (since we don't want a long-running transaction). */
     std::vector<BuildID> newIDs;
-    std::map<BuildID, Build::ptr> newBuildsByID;
+    std::unordered_map<BuildID, Build::ptr> newBuildsByID;
     std::multimap<StorePath, BuildID> newBuildsByPath;
 
-    unsigned int newLastBuildId = lastBuildId;
-
     {
         pqxx::work txn(conn);
 
@@ -106,17 +112,12 @@ bool State::getQueuedBuilds(Connection & conn,
              "jobsets.name as jobset, job, drvPath, maxsilent, timeout, timestamp, "
              "globalPriority, priority from Builds "
              "inner join jobsets on builds.jobset_id = jobsets.id "
-             "where builds.id > $1 and finished = 0 order by globalPriority desc, builds.id",
-            lastBuildId);
+             "where finished = 0 order by globalPriority desc, random()");
 
         for (auto const & row : res) {
             auto builds_(builds.lock());
             BuildID id = row["id"].as<BuildID>();
             if (buildOne && id != buildOne) continue;
-            if (id > newLastBuildId) {
-                newLastBuildId = id;
-                prom.queue_max_id.Set(id);
-            }
             if (builds_->count(id)) continue;
 
             auto build = std::make_shared<Build>(
@@ -318,15 +319,13 @@ bool State::getQueuedBuilds(Connection & conn,
 
         /* Stop after a certain time to allow priority bumps to be
            processed. */
-        if (std::chrono::system_clock::now() > start + std::chrono::seconds(600)) {
+        if (std::chrono::system_clock::now() > start + std::chrono::seconds(60)) {
             prom.queue_checks_early_exits.Increment();
             break;
         }
     }
 
     prom.queue_checks_finished.Increment();
-
-    lastBuildId = newBuildsByID.empty() ? newLastBuildId : newBuildsByID.begin()->first - 1;
     return newBuildsByID.empty();
 }
 
@@ -405,6 +404,34 @@ void State::processQueueChange(Connection & conn)
 }
 
 
+std::map<DrvOutput, std::optional<StorePath>> State::getMissingRemotePaths(
+    ref<Store> destStore,
+    const std::map<DrvOutput, std::optional<StorePath>> & paths)
+{
+    Sync<std::map<DrvOutput, std::optional<StorePath>>> missing_;
+    ThreadPool tp;
+
+    for (auto & [output, maybeOutputPath] : paths) {
+        if (!maybeOutputPath) {
+            auto missing(missing_.lock());
+            missing->insert({output, maybeOutputPath});
+        } else {
+            tp.enqueue([&] {
+                if (!destStore->isValidPath(*maybeOutputPath)) {
+                    auto missing(missing_.lock());
+                    missing->insert({output, maybeOutputPath});
+                }
+            });
+        }
+    }
+
+    tp.process();
+
+    auto missing(missing_.lock());
+    return *missing;
+}
+
+
 Step::ptr State::createStep(ref<Store> destStore,
     Connection & conn, Build::ptr build, const StorePath & drvPath,
     Build::ptr referringBuild, Step::ptr referringStep, std::set<StorePath> & finishedDrvs,
@@ -485,16 +512,15 @@ Step::ptr State::createStep(ref<Store> destStore,
 
     /* Are all outputs valid? */
     auto outputHashes = staticOutputHashes(*localStore, *(step->drv));
-    bool valid = true;
-    std::map<DrvOutput, std::optional<StorePath>> missing;
+    std::map<DrvOutput, std::optional<StorePath>> paths;
     for (auto & [outputName, maybeOutputPath] : destStore->queryPartialDerivationOutputMap(drvPath, &*localStore)) {
         auto outputHash = outputHashes.at(outputName);
-        if (maybeOutputPath && destStore->isValidPath(*maybeOutputPath))
-            continue;
-        valid = false;
-        missing.insert({{outputHash, outputName}, maybeOutputPath});
+        paths.insert({{outputHash, outputName}, maybeOutputPath});
     }
 
+    auto missing = getMissingRemotePaths(destStore, paths);
+    bool valid = missing.empty();
+
     /* Try to copy the missing paths from the local store or from
        substitutes. */
     if (!missing.empty()) {

src/hydra-queue-runner/state.hh

@@ -7,6 +7,7 @@
 #include <memory>
 #include <queue>
 #include <regex>
+#include <semaphore>
 
 #include <prometheus/counter.h>
 #include <prometheus/gauge.h>
@@ -58,6 +59,7 @@ typedef enum {
     ssConnecting = 10,
     ssSendingInputs = 20,
     ssBuilding = 30,
+    ssWaitingForLocalSlot = 35,
     ssReceivingOutputs = 40,
     ssPostProcessing = 50,
 } StepState;
@@ -361,6 +363,10 @@ private:
     typedef std::map<std::string, Machine::ptr> Machines;
     nix::Sync<Machines> machines; // FIXME: use atomic_shared_ptr
 
+    /* Throttler for CPU-bound local work. */
+    static constexpr unsigned int maxSupportedLocalWorkers = 1024;
+    std::counting_semaphore<maxSupportedLocalWorkers> localWorkThrottler;
+
     /* Various stats. */
     time_t startedAt;
     counter nrBuildsRead{0};
@@ -370,6 +376,7 @@ private:
     counter nrStepsDone{0};
     counter nrStepsBuilding{0};
     counter nrStepsCopyingTo{0};
+    counter nrStepsWaitingForDownloadSlot{0};
     counter nrStepsCopyingFrom{0};
     counter nrStepsWaiting{0};
     counter nrUnsupportedSteps{0};
@@ -458,7 +465,12 @@ private:
         prometheus::Counter& queue_steps_created;
         prometheus::Counter& queue_checks_early_exits;
         prometheus::Counter& queue_checks_finished;
-        prometheus::Gauge& queue_max_id;
+
+        prometheus::Counter& dispatcher_time_spent_running;
+        prometheus::Counter& dispatcher_time_spent_waiting;
+
+        prometheus::Counter& queue_monitor_time_spent_running;
+        prometheus::Counter& queue_monitor_time_spent_waiting;
 
         PromMetrics();
     };
@@ -502,8 +514,7 @@ private:
     void queueMonitorLoop(Connection & conn);
 
     /* Check the queue for new builds. */
-    bool getQueuedBuilds(Connection & conn,
-        nix::ref<nix::Store> destStore, unsigned int & lastBuildId);
+    bool getQueuedBuilds(Connection & conn, nix::ref<nix::Store> destStore);
 
     /* Handle cancellation, deletion and priority bumps. */
     void processQueueChange(Connection & conn);
@@ -511,6 +522,12 @@ private:
     BuildOutput getBuildOutputCached(Connection & conn, nix::ref<nix::Store> destStore,
         const nix::StorePath & drvPath);
 
+    /* Returns paths missing from the remote store. Paths are processed in
+     * parallel to work around the possible latency of remote stores. */
+    std::map<nix::DrvOutput, std::optional<nix::StorePath>> getMissingRemotePaths(
+        nix::ref<nix::Store> destStore,
+        const std::map<nix::DrvOutput, std::optional<nix::StorePath>> & paths);
+
     Step::ptr createStep(nix::ref<nix::Store> store,
         Connection & conn, Build::ptr build, const nix::StorePath & drvPath,
         Build::ptr referringBuild, Step::ptr referringStep, std::set<nix::StorePath> & finishedDrvs,
@@ -546,10 +563,11 @@ private:
        retried. */
     enum StepResult { sDone, sRetry, sMaybeCancelled };
     StepResult doBuildStep(nix::ref<nix::Store> destStore,
-        MachineReservation::ptr reservation,
+        MachineReservation::ptr & reservation,
         std::shared_ptr<ActiveStep> activeStep);
 
     void buildRemote(nix::ref<nix::Store> destStore,
+        MachineReservation::ptr & reservation,
         Machine::ptr machine, Step::ptr step,
         const nix::ServeProto::BuildOptions & buildOptions,
         RemoteResult & result, std::shared_ptr<ActiveStep> activeStep,

src/lib/Hydra/Controller/Build.pm

@@ -238,7 +238,7 @@ sub serveFile {
         # XSS hole.
         $c->response->header('Content-Security-Policy' => 'sandbox allow-scripts');
 
-        $c->stash->{'plain'} = { data => grab(cmd => ["nix", "--experimental-features", "nix-command",
+        $c->stash->{'plain'} = { data => readIntoSocket(cmd => ["nix", "--experimental-features", "nix-command",
                                                       "store", "cat", "--store", getStoreUri(), "$path"]) };
 
         # Detect MIME type.

src/lib/Hydra/Controller/Jobset.pm

@@ -364,6 +364,21 @@ sub evals_GET {
     );
 }
 
+sub errors :Chained('jobsetChain') :PathPart('errors') :Args(0) :ActionClass('REST') { }
+
+sub errors_GET {
+    my ($self, $c) = @_;
+
+    $c->stash->{template} = 'eval-error.tt';
+
+    my $jobsetName = $c->stash->{params}->{name};
+    $c->stash->{jobset} = $c->stash->{project}->jobsets->find(
+        { name => $jobsetName },
+        { '+columns' => { 'errormsg' => 'errormsg' } }
+    );
+
+    $self->status_ok($c, entity => $c->stash->{jobset});
+}
 
 # Redirect to the latest finished evaluation of this jobset.
 sub latest_eval : Chained('jobsetChain') PathPart('latest-eval') {

src/lib/Hydra/Controller/JobsetEval.pm

@@ -86,6 +86,17 @@ sub view_GET {
     );
 }
 
+sub errors :Chained('evalChain') :PathPart('errors') :Args(0) :ActionClass('REST') { }
+
+sub errors_GET {
+    my ($self, $c) = @_;
+
+    $c->stash->{template} = 'eval-error.tt';
+
+    $c->stash->{eval} = $c->model('DB::JobsetEvals')->find($c->stash->{eval}->id, { prefetch => 'evaluationerror' });
+
+    $self->status_ok($c, entity => $c->stash->{eval});
+}
 
 sub create_jobset : Chained('evalChain') PathPart('create-jobset') Args(0) {
     my ($self, $c) = @_;

src/lib/Hydra/Controller/Root.pm

@@ -51,6 +51,7 @@ sub begin :Private {
     $c->stash->{curUri} = $c->request->uri;
     $c->stash->{version} = $ENV{"HYDRA_RELEASE"} || "<devel>";
     $c->stash->{nixVersion} = $ENV{"NIX_RELEASE"} || "<devel>";
+    $c->stash->{nixEvalJobsVersion} = $ENV{"NIX_EVAL_JOBS_RELEASE"} || "<devel>";
     $c->stash->{curTime} = time;
     $c->stash->{logo} = defined $c->config->{hydra_logo} ? "/logo" : "";
     $c->stash->{tracker} = defined $c->config->{tracker} ? $c->config->{tracker} : "";
@@ -161,7 +162,7 @@ sub status_GET {
             { "buildsteps.busy" => { '!=', 0 } },
             { order_by => ["globalpriority DESC", "id"],
               join => "buildsteps",
-              columns => [@buildListColumns]
+              columns => [@buildListColumns, 'buildsteps.drvpath', 'buildsteps.type']
             })]
     );
 }

src/lib/Hydra/Helper/BuildDiff.pm

@@ -37,7 +37,16 @@ sub buildDiff {
 
     my $n = 0;
     foreach my $build (@{$builds}) {
-        my $aborted = $build->finished != 0 && ($build->buildstatus == 3 || $build->buildstatus == 4);
+        my $aborted = $build->finished != 0 && (
+            # aborted
+            $build->buildstatus == 3
+            # cancelled
+            || $build->buildstatus == 4
+            # timeout
+            || $build->buildstatus == 7
+            # log limit exceeded
+            || $build->buildstatus == 10
+        );
         my $d;
         my $found = 0;
         while ($n < scalar(@{$builds2})) {
@@ -79,4 +88,4 @@ sub buildDiff {
     return $ret;
 }
 
-1;
+1;

src/lib/Hydra/Helper/Nix.pm

@@ -36,6 +36,7 @@ our @EXPORT = qw(
     jobsetOverview
     jobsetOverview_
     pathIsInsidePrefix
+    readIntoSocket
     readNixFile
     registerRoot
     restartBuilds
@@ -296,8 +297,7 @@ sub getEvals {
 
     my @evals = $evals_result_set->search(
         { hasnewbuilds => 1 },
-        { order_by => "$me.id DESC", rows => $rows, offset => $offset
-        , prefetch => { evaluationerror => [ ] } });
+        { order_by => "$me.id DESC", rows => $rows, offset => $offset });
     my @res = ();
     my $cache = {};
 
@@ -417,6 +417,16 @@ sub pathIsInsidePrefix {
     return $cur;
 }
 
+sub readIntoSocket{
+    my (%args) = @_;
+    my $sock;
+
+    eval {
+        open($sock, "-|", @{$args{cmd}}) or die q(failed to open socket from command:\n $x);
+    };
+
+    return $sock;
+}
 
 
 

src/lib/Hydra/Schema/Result/EvaluationErrors.pm

@@ -105,4 +105,6 @@ __PACKAGE__->add_column(
     "+id" => { retrieve_on_insert => 1 }
 );
 
+__PACKAGE__->mk_group_accessors('column' => 'has_error');
+
 1;

src/lib/Hydra/Schema/Result/Jobsets.pm

@@ -386,6 +386,8 @@ __PACKAGE__->add_column(
     "+id" => { retrieve_on_insert => 1 }
 );
 
+__PACKAGE__->mk_group_accessors('column' => 'has_error');
+
 sub supportsDynamicRunCommand {
   my ($self) = @_;
 

src/lib/Hydra/Schema/ResultSet/EvaluationErrors.pm

@@ -0,0 +1,30 @@
+package Hydra::Schema::ResultSet::EvaluationErrors;
+
+use strict;
+use utf8;
+use warnings;
+
+use parent 'DBIx::Class::ResultSet';
+
+use Storable qw(dclone);
+
+__PACKAGE__->load_components('Helper::ResultSet::RemoveColumns');
+
+# Exclude expensive error message values unless explicitly requested, and
+# replace them with a summary field describing their presence/absence.
+sub search_rs {
+  my ( $class, $query, $attrs ) = @_;
+
+  if ($attrs) {
+    $attrs = dclone($attrs);
+  }
+
+  unless (exists $attrs->{'select'} || exists $attrs->{'columns'}) {
+    $attrs->{'+columns'}->{'has_error'} = "errormsg != ''";
+  }
+  unless (exists $attrs->{'+columns'}->{'errormsg'}) {
+    push @{ $attrs->{'remove_columns'} }, 'errormsg';
+  }
+
+  return $class->next::method($query, $attrs);
+}

src/lib/Hydra/Schema/ResultSet/Jobsets.pm

@@ -0,0 +1,30 @@
+package Hydra::Schema::ResultSet::Jobsets;
+
+use strict;
+use utf8;
+use warnings;
+
+use parent 'DBIx::Class::ResultSet';
+
+use Storable qw(dclone);
+
+__PACKAGE__->load_components('Helper::ResultSet::RemoveColumns');
+
+# Exclude expensive error message values unless explicitly requested, and
+# replace them with a summary field describing their presence/absence.
+sub search_rs {
+  my ( $class, $query, $attrs ) = @_;
+
+  if ($attrs) {
+    $attrs = dclone($attrs);
+  }
+
+  unless (exists $attrs->{'select'} || exists $attrs->{'columns'}) {
+    $attrs->{'+columns'}->{'has_error'} = "errormsg != ''";
+  }
+  unless (exists $attrs->{'+columns'}->{'errormsg'}) {
+    push @{ $attrs->{'remove_columns'} }, 'errormsg';
+  }
+
+  return $class->next::method($query, $attrs);
+}

src/meson.build

@@ -1,6 +1,5 @@
 # Native code
 subdir('libhydra')
-subdir('hydra-eval-jobs')
 subdir('hydra-evaluator')
 subdir('hydra-queue-runner')
 

src/root/build.tt

@@ -61,21 +61,7 @@ END;
             <td>[% IF step.busy != 0 || ((step.machine || step.starttime) && (step.status == 0 || step.status == 1 || step.status == 3 || step.status == 4 || step.status == 7)); INCLUDE renderMachineName machine=step.machine; ELSE; "<em>n/a</em>"; END %]</td>
             <td class="step-status">
               [% IF step.busy != 0 %]
-                [% IF step.busy == 1 %]
-                  <strong>Preparing</strong>
-                [% ELSIF step.busy == 10 %]
-                  <strong>Connecting</strong>
-                [% ELSIF step.busy == 20 %]
-                  <strong>Sending inputs</strong>
-                [% ELSIF step.busy == 30 %]
-                  <strong>Building</strong>
-                [% ELSIF step.busy == 40 %]
-                  <strong>Receiving outputs</strong>
-                [% ELSIF step.busy == 50 %]
-                  <strong>Post-processing</strong>
-                [% ELSE %]
-                  <strong>Unknown state</strong>
-                [% END %]
+                [% INCLUDE renderBusyStatus %]
               [% ELSIF step.status == 0 %]
                 [% IF step.isnondeterministic %]
                   <span class="warn">Succeeded with non-determistic result</span>

src/root/common.tt

@@ -91,6 +91,17 @@ BLOCK renderDuration;
   duration % 60 %]s[%
 END;
 
+BLOCK renderDrvInfo;
+  drvname = step.drvpath
+    .substr(11) # strip `/nix/store/`
+    .split('-').slice(1).join("-") # strip hash part
+    .substr(0, -4); # strip `.drv`
+  IF drvname != releasename;
+    IF step.type == 0; action = "Build"; ELSE; action = "Substitution"; END;
+    IF drvname; %]<em> ([% action %] of [% drvname %])</em>[% END;
+  END;
+END;
+
 
 BLOCK renderBuildListHeader %]
   <table class="table table-striped table-condensed clickable-rows">
@@ -131,7 +142,12 @@ BLOCK renderBuildListBody;
       [% END %]
       <td><a class="row-link" href="[% link %]">[% build.id %]</a></td>
       [% IF !hideJobName %]
-        <td><a href="[%link%]">[% IF !hideJobsetName %][%build.jobset.get_column("project")%]:[%build.jobset.get_column("name")%]:[% END %][%build.get_column("job")%]</td>
+        <td>
+          <a href="[%link%]">[% IF !hideJobsetName %][%build.jobset.get_column("project")%]:[%build.jobset.get_column("name")%]:[% END %][%build.get_column("job")%]</a>
+          [% IF showStepName %]
+            [% INCLUDE renderDrvInfo step=build.buildsteps releasename=build.nixname %]
+          [% END %]
+        </td>
       [% END %]
       <td class="nowrap">[% t = showSchedulingInfo ? build.timestamp : build.stoptime; IF t; INCLUDE renderRelativeDate timestamp=(showSchedulingInfo ? build.timestamp : build.stoptime); ELSE; "-"; END %]</td>
       <td>[% !showSchedulingInfo and build.get_column('releasename') ? build.get_column('releasename') : build.nixname %]</td>
@@ -245,6 +261,27 @@ BLOCK renderBuildStatusIcon;
 END;
 
 
+BLOCK renderBusyStatus;
+  IF step.busy == 1 %]
+    <strong>Preparing</strong>
+  [% ELSIF step.busy == 10 %]
+    <strong>Connecting</strong>
+  [% ELSIF step.busy == 20 %]
+    <strong>Sending inputs</strong>
+  [% ELSIF step.busy == 30 %]
+    <strong>Building</strong>
+  [% ELSIF step.busy == 35 %]
+    <strong>Waiting to receive outputs</strong>
+  [% ELSIF step.busy == 40 %]
+    <strong>Receiving outputs</strong>
+  [% ELSIF step.busy == 50 %]
+    <strong>Post-processing</strong>
+  [% ELSE %]
+    <strong>Unknown state</strong>
+  [% END;
+END;
+
+
 BLOCK renderStatus;
   IF build.finished;
     buildstatus = build.buildstatus;
@@ -476,7 +513,7 @@ BLOCK renderEvals %]
             ELSE %]
              -
             [% END %]
-            [% IF eval.evaluationerror.errormsg %]
+            [% IF eval.evaluationerror.has_error %]
               <span class="badge badge-warning">Eval Errors</span>
             [% END %]
           </td>
@@ -602,7 +639,7 @@ BLOCK renderJobsetOverview %]
         <td>[% HTML.escape(j.description) %]</td>
         <td>[% IF j.lastcheckedtime;
                  INCLUDE renderDateTime timestamp = j.lastcheckedtime;
-                 IF j.errormsg || j.fetcherrormsg; %]&nbsp;<span class = 'badge badge-warning'>Error</span>[% END;
+                 IF j.has_error || j.fetcherrormsg; %]&nbsp;<span class = 'badge badge-warning'>Error</span>[% END;
                  ELSE; "-";
                END %]</td>
         [% IF j.get_column('nrtotal') > 0 %]

src/root/eval-error.tt

@@ -0,0 +1,26 @@
+[% PROCESS common.tt %]
+<!DOCTYPE html>
+
+<html lang="en">
+
+  <head>
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+    <meta http-equiv="X-UA-Compatible" content="IE=Edge" />
+    [% INCLUDE style.tt %]
+  </head>
+
+  <body>
+
+    <div class="tab-content tab-pane">
+        <div id="tabs-errors" class="">
+          [% IF jobset %]
+              <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(jobset.errortime || jobset.lastcheckedtime) %].</p>
+              <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(jobset.fetcherrormsg || jobset.errormsg) %]</pre></div></div>
+          [% ELSIF eval %]
+              <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(eval.evaluationerror.errortime || eval.timestamp) %].</p>
+              <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(eval.evaluationerror.errormsg) %]</pre></div></div>
+          [% END %]
+        </div>
+    </div>
+  </body>
+</html>

src/root/jobset-eval.tt

@@ -65,7 +65,7 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),
   [% END %]
 
   [% IF aborted.size > 0 %]
-    <li class="nav-item"><a class="nav-link" href="#tabs-aborted" data-toggle="tab"><span class="text-warning">Aborted Jobs ([% aborted.size %])</span></a></li>
+    <li class="nav-item"><a class="nav-link" href="#tabs-aborted" data-toggle="tab"><span class="text-warning">Aborted / Timed out Jobs ([% aborted.size %])</span></a></li>
   [% END %]
   [% IF nowFail.size > 0 %]
     <li class="nav-item"><a class="nav-link" href="#tabs-now-fail" data-toggle="tab"><span class="text-warning">Newly Failing Jobs ([% nowFail.size %])</span></a></li>
@@ -90,7 +90,7 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),
   [% END %]
   <li class="nav-item"><a class="nav-link" href="#tabs-inputs" data-toggle="tab">Inputs</a></li>
 
-  [% IF eval.evaluationerror.errormsg %]
+  [% IF eval.evaluationerror.has_error %]
     <li class="nav-item"><a class="nav-link" href="#tabs-errors" data-toggle="tab"><span class="text-warning">Evaluation Errors</span></a></li>
   [% END %]
 </ul>
@@ -108,13 +108,6 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),
 
 <div class="tab-content">
 
-  [% IF eval.evaluationerror.errormsg %]
-    <div id="tabs-errors" class="tab-pane">
-      <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(eval.evaluationerror.errortime || eval.timestamp) %].</p>
-      <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(eval.evaluationerror.errormsg) %]</pre></div></div>
-    </div>
-  [% END %]
-
   <div id="tabs-aborted" class="tab-pane">
     [% INCLUDE renderSome builds=aborted tabname="#tabs-aborted" %]
   </div>
@@ -172,10 +165,9 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),
     [% END %]
   </div>
 
-  [% IF eval.evaluationerror.errormsg %]
+  [% IF eval.evaluationerror.has_error %]
     <div id="tabs-errors" class="tab-pane">
-      <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(eval.evaluationerror.errortime || eval.timestamp) %].</p>
-      <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(eval.evaluationerror.errormsg) %]</pre></div></div>
+      <iframe src="[% c.uri_for(c.controller('JobsetEval').action_for('errors'), [eval.id], params) %]" loading="lazy" frameBorder="0" width="100%"></iframe>
     </div>
   [% END %]
 </div>

src/root/jobset.tt

@@ -61,7 +61,7 @@
   [% END %]
 
   <li class="nav-item"><a class="nav-link active" href="#tabs-evaluations" data-toggle="tab">Evaluations</a></li>
-  [% IF jobset.errormsg || jobset.fetcherrormsg %]
+  [% IF jobset.has_error || jobset.fetcherrormsg %]
     <li class="nav-item"><a class="nav-link" href="#tabs-errors" data-toggle="tab"><span class="text-warning">Evaluation Errors</span></a></li>
   [% END %]
   <li class="nav-item"><a class="nav-link" href="#tabs-jobs" data-toggle="tab">Jobs</a></li>
@@ -79,7 +79,7 @@
         <th>Last checked:</th>
         <td>
           [% IF jobset.lastcheckedtime %]
-            [% INCLUDE renderDateTime timestamp = jobset.lastcheckedtime %], [% IF jobset.errormsg || jobset.fetcherrormsg %]<em class="text-warning">with errors!</em>[% ELSE %]<em>no errors</em>[% END %]
+            [% INCLUDE renderDateTime timestamp = jobset.lastcheckedtime %], [% IF jobset.has_error || jobset.fetcherrormsg %]<em class="text-warning">with errors!</em>[% ELSE %]<em>no errors</em>[% END %]
           [% ELSE %]
             <em>never</em>
           [% END %]
@@ -117,10 +117,9 @@
 
   </div>
 
-  [% IF jobset.errormsg || jobset.fetcherrormsg %]
+  [% IF jobset.has_error || jobset.fetcherrormsg %]
     <div id="tabs-errors" class="tab-pane">
-      <p>Errors occurred at [% INCLUDE renderDateTime timestamp=(jobset.errortime || jobset.lastcheckedtime) %].</p>
-      <div class="card bg-light"><div class="card-body"><pre>[% HTML.escape(jobset.fetcherrormsg || jobset.errormsg) %]</pre></div></div>
+      <iframe src="[% c.uri_for('/jobset' project.name jobset.name "errors") %]" loading="lazy" frameBorder="0" width="100%"></iframe>
     </div>
   [% END %]
 

src/root/layout.tt

@@ -10,31 +10,7 @@
 
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
     <meta http-equiv="X-UA-Compatible" content="IE=Edge" />
-
-    <script type="text/javascript" src="[% c.uri_for("/static/js/jquery/jquery-3.4.1.min.js") %]"></script>
-    <script type="text/javascript" src="[% c.uri_for("/static/js/jquery/jquery-ui-1.10.4.min.js") %]"></script>
-    <script type="text/javascript" src="[% c.uri_for("/static/js/moment/moment-2.24.0.min.js") %]"></script>
-
-    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-
-    <link href="[% c.uri_for("/static/fontawesome/css/all.css") %]" rel="stylesheet" />
-    <script type="text/javascript" src="[% c.uri_for("/static/js/popper.min.js") %]"></script>
-    <script type="text/javascript" src="[% c.uri_for("/static/bootstrap/js/bootstrap.min.js") %]"></script>
-    <link href="[% c.uri_for("/static/bootstrap/css/bootstrap.min.css") %]" rel="stylesheet" />
-
-    <!-- hydra.css may need to be moved to before boostrap to make the @media rule work. -->
-    <link rel="stylesheet" href="[% c.uri_for("/static/css/hydra.css") %]" type="text/css" />
-    <link rel="stylesheet" href="[% c.uri_for("/static/css/rotated-th.css") %]" type="text/css" />
-
-    <style>
-      .popover { max-width: 40%; }
-    </style>
-
-    <script type="text/javascript" src="[% c.uri_for("/static/js/bootbox.min.js") %]"></script>
-
-    <link rel="stylesheet" href="[% c.uri_for("/static/css/tree.css") %]" type="text/css" />
-
-    <script type="text/javascript" src="[% c.uri_for("/static/js/common.js") %]"></script>
+    [% INCLUDE style.tt %]
 
     [% IF c.config.enable_google_login %]
       <meta name="google-signin-client_id" content="[% c.config.google_client_id %]">
@@ -93,7 +69,7 @@
       <footer class="navbar">
         <hr />
         <small>
-          <em><a href="http://nixos.org/hydra" target="_blank" class="squiggle">Hydra</a> [% HTML.escape(version) %] (using [% HTML.escape(nixVersion) %]).</em>
+          <em><a href="http://nixos.org/hydra" target="_blank" class="squiggle">Hydra</a> [% HTML.escape(version) %] (using [% HTML.escape(nixVersion) %] and [% HTML.escape(nixEvalJobsVersion) %]).</em>
           [% IF c.user_exists %]
           You are signed in as <tt>[% HTML.escape(c.user.username) %]</tt>
             [%- IF c.user.type == 'google' %] via Google[% END %].

src/root/machine-status.tt

@@ -6,10 +6,10 @@
   <thead>
     <tr>
       <th>Job</th>
-      <th>System</th>
       <th>Build</th>
       <th>Step</th>
       <th>What</th>
+      <th>Status</th>
       <th>Since</th>
     </tr>
   </thead>
@@ -40,10 +40,10 @@
           [% idle = 0 %]
           <tr>
             <td><tt>[% INCLUDE renderFullJobName project=step.project jobset=step.jobset job=step.job %]</tt></td>
-            <td><tt>[% step.system %]</tt></td>
             <td><a href="[% c.uri_for('/build' step.build) %]">[% step.build %]</a></td>
             <td>[% IF step.busy >= 30 %]<a class="row-link" href="[% c.uri_for('/build' step.build 'nixlog' step.stepnr 'tail') %]">[% step.stepnr %]</a>[% ELSE; step.stepnr; END %]</td>
             <td><tt>[% step.drvpath.match('-(.*)').0 %]</tt></td>
+            <td>[% INCLUDE renderBusyStatus %]</td>
             <td style="width: 10em">[% INCLUDE renderDuration duration = curTime - step.starttime %] </td>
           </tr>
         [% END %]

src/root/static/js/common.js

@@ -129,6 +129,12 @@ $(document).ready(function() {
             el.addClass("is-local");
         }
     });
+
+    [...document.getElementsByTagName("iframe")].forEach((element) => {
+        element.contentWindow.addEventListener("DOMContentLoaded", (_) => {
+            element.style.height = element.contentWindow.document.body.scrollHeight + 'px';
+        })
+    })
 });
 
 var tabsLoaded = {};

src/root/status.tt

@@ -7,7 +7,7 @@
 
 [% ELSE %]
 
-  [% INCLUDE renderBuildList builds=resource showSchedulingInfo=1 hideResultInfo=1 busy=1 %]
+  [% INCLUDE renderBuildList builds=resource showSchedulingInfo=1 hideResultInfo=1 busy=1 showStepName=1 %]
 
 [% END %]
 

src/root/style.tt

@@ -0,0 +1,24 @@
+<script type="text/javascript" src="[% c.uri_for("/static/js/jquery/jquery-3.4.1.min.js") %]"></script>
+<script type="text/javascript" src="[% c.uri_for("/static/js/jquery/jquery-ui-1.10.4.min.js") %]"></script>
+<script type="text/javascript" src="[% c.uri_for("/static/js/moment/moment-2.24.0.min.js") %]"></script>
+
+<meta name="viewport" content="width=device-width, initial-scale=1.0" />
+
+<link href="[% c.uri_for("/static/fontawesome/css/all.css") %]" rel="stylesheet" />
+<script type="text/javascript" src="[% c.uri_for("/static/js/popper.min.js") %]"></script>
+<script type="text/javascript" src="[% c.uri_for("/static/bootstrap/js/bootstrap.min.js") %]"></script>
+<link href="[% c.uri_for("/static/bootstrap/css/bootstrap.min.css") %]" rel="stylesheet" />
+
+<!-- hydra.css may need to be moved to before boostrap to make the @media rule work. -->
+<link rel="stylesheet" href="[% c.uri_for("/static/css/hydra.css") %]" type="text/css" />
+<link rel="stylesheet" href="[% c.uri_for("/static/css/rotated-th.css") %]" type="text/css" />
+
+<style>
+  .popover { max-width: 40%; }
+</style>
+
+<script type="text/javascript" src="[% c.uri_for("/static/js/bootbox.min.js") %]"></script>
+
+<link rel="stylesheet" href="[% c.uri_for("/static/css/tree.css") %]" type="text/css" />
+
+<script type="text/javascript" src="[% c.uri_for("/static/js/common.js") %]"></script>

src/script/hydra-eval-jobset

@@ -17,6 +17,7 @@ use Hydra::Helper::Nix;
 use Hydra::Model::DB;
 use Hydra::Plugin;
 use Hydra::Schema;
+use IPC::Run;
 use JSON::MaybeXS;
 use Net::Statsd;
 use Nix::Store;
@@ -357,22 +358,32 @@ sub evalJobs {
     my @cmd;
 
     if (defined $flakeRef) {
-        @cmd = ("hydra-eval-jobs",
-                "--flake", $flakeRef,
-                "--gc-roots-dir", getGCRootsDir,
-                "--max-jobs", 1);
+        my $nix_expr =
+            "let " .
+            "flake = builtins.getFlake (toString \"$flakeRef\"); " .
+            "in " .
+            "flake.hydraJobs " .
+            "or flake.checks " .
+            "or (throw \"flake '$flakeRef' does not provide any Hydra jobs or checks\")";
+
+        @cmd = ("nix-eval-jobs", "--expr", $nix_expr);
     } else {
         my $nixExprInput = $inputInfo->{$nixExprInputName}->[0]
             or die "cannot find the input containing the job expression\n";
 
-        @cmd = ("hydra-eval-jobs",
+        @cmd = ("nix-eval-jobs",
                 "<" . $nixExprInputName . "/" . $nixExprPath . ">",
-                "--gc-roots-dir", getGCRootsDir,
-                "--max-jobs", 1,
                 inputsToArgs($inputInfo));
     }
 
-    push @cmd, "--no-allow-import-from-derivation" if $config->{allow_import_from_derivation} // "true" ne "true";
+    push @cmd, ("--gc-roots-dir", getGCRootsDir);
+    push @cmd, ("--max-jobs", 1);
+    push @cmd, "--meta";
+    push @cmd, "--constituents";
+    push @cmd, "--force-recurse";
+    push @cmd, ("--option", "allow-import-from-derivation", "false") if $config->{allow_import_from_derivation} // "true" ne "true";
+    push @cmd, ("--workers", $config->{evaluator_workers} // 1);
+    push @cmd, ("--max-memory-size", $config->{evaluator_max_memory_size} // 4096);
 
     if (defined $ENV{'HYDRA_DEBUG'}) {
         sub escape {
@@ -384,14 +395,40 @@ sub evalJobs {
         print STDERR "evaluator: @escaped\n";
     }
 
-    (my $res, my $jobsJSON, my $stderr) = captureStdoutStderr(21600, @cmd);
-    die "hydra-eval-jobs returned " . ($res & 127 ? "signal $res" : "exit code " . ($res >> 8))
-        . ":\n" . ($stderr ? decode("utf-8", $stderr) : "(no output)\n")
-        if $res;
+    my $evalProc = IPC::Run::start \@cmd,
+            '>', IPC::Run::new_chunker, \my $out,
+            '2>', \my $err;
 
-    print STDERR "$stderr";
+    return sub {
+        while (1) {
+            $evalProc->pump;
+            if (!defined $out && !defined $err) {
+                $evalProc->finish;
+                if ($?) {
+                    die "nix-eval-jobs returned " . ($? & 127 ? "signal $?" : "exit code " . ($? >> 8)) . "\n";
+                }
+                return;
+            }
 
-    return decode_json($jobsJSON);
+            if (defined $err) {
+                print STDERR "$err";
+                undef $err;
+            }
+
+            if (defined $out && $out ne '') {
+                my $job;
+                try {
+                    $job = decode_json($out);
+                } catch {
+                    warn "nix-eval-jobs sent invalid JSON.\n  parse error: $_\n  invalid json: $out\n";
+                };
+                undef $out;
+                if (defined $job) {
+                    return $job;
+                }
+            }
+        }
+    };
 }
 
 
@@ -420,7 +457,7 @@ sub checkBuild {
     my $firstOutputName = $outputNames[0];
     my $firstOutputPath = $buildInfo->{outputs}->{$firstOutputName};
 
-    my $jobName = $buildInfo->{jobName} or die;
+    my $jobName = $buildInfo->{attr} or die;
     my $drvPath = $buildInfo->{drvPath} or die;
 
     my $build;
@@ -474,9 +511,30 @@ sub checkBuild {
 
         my $time = time();
 
-        sub null {
-            my ($s) = @_;
-            return $s eq "" ? undef : $s;
+        sub getMeta {
+            my ($s, $def) = @_;
+            return ($s || "") eq "" ? $def : $s;
+        }
+
+        sub getMetaStrings {
+            my ($v, $k, $acc) = @_;
+            my $t = ref $v;
+
+            if ($t eq 'HASH') {
+                push @$acc, $v->{$k} if exists $v->{$k};
+            } elsif ($t eq 'ARRAY') {
+                getMetaStrings($_, $k, $acc) foreach @$v;
+            } elsif (defined $v) {
+                push @$acc, $v;
+            }
+        }
+
+        sub getMetaConcatStrings {
+            my ($v, $k) = @_;
+
+            my @strings;
+            getMetaStrings($v, $k, \@strings);
+            return join(", ", @strings) || undef;
         }
 
         # Add the build to the database.
@@ -484,19 +542,19 @@ sub checkBuild {
             { timestamp => $time
             , jobset_id => $jobset->id
             , job => $jobName
-            , description => null($buildInfo->{description})
-            , license => null($buildInfo->{license})
-            , homepage => null($buildInfo->{homepage})
-            , maintainers => null($buildInfo->{maintainers})
-            , maxsilent => $buildInfo->{maxSilent}
-            , timeout => $buildInfo->{timeout}
-            , nixname => $buildInfo->{nixName}
+            , description => getMeta($buildInfo->{meta}->{description}, undef)
+            , license => getMetaConcatStrings($buildInfo->{meta}->{license}, "shortName")
+            , homepage => getMeta($buildInfo->{meta}->{homepage}, undef)
+            , maintainers => getMetaConcatStrings($buildInfo->{meta}->{maintainers}, "email")
+            , maxsilent => getMeta($buildInfo->{meta}->{maxSilent}, 7200)
+            , timeout => getMeta($buildInfo->{meta}->{timeout}, 36000)
+            , nixname => $buildInfo->{name}
             , drvpath => $drvPath
             , system => $buildInfo->{system}
-            , priority => $buildInfo->{schedulingPriority}
+            , priority => getMeta($buildInfo->{meta}->{schedulingPriority}, 100)
             , finished => 0
             , iscurrent => 1
-            , ischannel => $buildInfo->{isChannel}
+            , ischannel => getMeta($buildInfo->{meta}->{isChannel}, 0)
             });
 
         $build->buildoutputs->create({ name => $_, path => $buildInfo->{outputs}->{$_} })
@@ -665,7 +723,7 @@ sub checkJobsetWrapped {
         return;
     }
 
-    # Hash the arguments to hydra-eval-jobs and check the
+    # Hash the arguments to nix-eval-jobs and check the
     # JobsetInputHashes to see if the previous evaluation had the same
     # inputs.  If so, bail out.
     my @args = ($jobset->nixexprinput // "", $jobset->nixexprpath // "", inputsToArgs($inputInfo));
@@ -687,19 +745,12 @@ sub checkJobsetWrapped {
 
     # Evaluate the job expression.
     my $evalStart = clock_gettime(CLOCK_MONOTONIC);
-    my $jobs = evalJobs($project->name . ":" . $jobset->name, $inputInfo, $jobset->nixexprinput, $jobset->nixexprpath, $flakeRef);
-    my $evalStop = clock_gettime(CLOCK_MONOTONIC);
-
-    if ($jobsetsJobset) {
-        my @keys = keys %$jobs;
-        die "The .jobsets jobset must only have a single job named 'jobsets'"
-            unless (scalar @keys) == 1 && $keys[0] eq "jobsets";
-    }
-    Net::Statsd::timing("hydra.evaluator.eval_time", int(($evalStop - $evalStart) * 1000));
+    my $evalStop;
+    my $jobsIter = evalJobs($project->name . ":" . $jobset->name, $inputInfo, $jobset->nixexprinput, $jobset->nixexprpath, $flakeRef);
 
     if ($dryRun) {
-        foreach my $name (keys %{$jobs}) {
-            my $job = $jobs->{$name};
+        while (defined(my $job = $jobsIter->())) {
+            my $name = $job->{attr};
             if (defined $job->{drvPath}) {
                 print STDERR "good job $name: $job->{drvPath}\n";
             } else {
@@ -709,36 +760,20 @@ sub checkJobsetWrapped {
         return;
     }
 
-    die "Jobset contains a job with an empty name. Make sure the jobset evaluates to an attrset of jobs.\n"
-        if defined $jobs->{""};
-
-    $jobs->{$_}->{jobName} = $_ for keys %{$jobs};
-
-    my $jobOutPathMap = {};
-    my $jobsetChanged = 0;
-    my $dbStart = clock_gettime(CLOCK_MONOTONIC);
-
-
     # Store the error messages for jobs that failed to evaluate.
     my $evaluationErrorTime = time;
     my $evaluationErrorMsg = "";
-    foreach my $job (values %{$jobs}) {
-        next unless defined $job->{error};
-        $evaluationErrorMsg .=
-            ($job->{jobName} ne "" ? "in job ‘$job->{jobName}’" : "at top-level") .
-            ":\n" . $job->{error} . "\n\n";
-    }
-    setJobsetError($jobset, $evaluationErrorMsg, $evaluationErrorTime);
-
     my $evaluationErrorRecord = $db->resultset('EvaluationErrors')->create(
         { errormsg => $evaluationErrorMsg
         , errortime => $evaluationErrorTime
         }
     );
 
+    my $jobOutPathMap = {};
+    my $jobsetChanged = 0;
     my %buildMap;
-    $db->txn_do(sub {
 
+    $db->txn_do(sub {
         my $prevEval = getPrevJobsetEval($db, $jobset, 1);
 
         # Clear the "current" flag on all builds.  Since we're in a
@@ -751,7 +786,7 @@ sub checkJobsetWrapped {
             , evaluationerror => $evaluationErrorRecord
             , timestamp => time
             , checkouttime => abs(int($checkoutStop - $checkoutStart))
-            , evaltime => abs(int($evalStop - $evalStart))
+            , evaltime => 0
             , hasnewbuilds => 0
             , nrbuilds => 0
             , flake => $flakeRef
@@ -759,11 +794,24 @@ sub checkJobsetWrapped {
             , nixexprpath => $jobset->nixexprpath
             });
 
-        # Schedule each successfully evaluated job.
-        foreach my $job (permute(values %{$jobs})) {
-            next if defined $job->{error};
-            #print STDERR "considering job " . $project->name, ":", $jobset->name, ":", $job->{jobName} . "\n";
-            checkBuild($db, $jobset, $ev, $inputInfo, $job, \%buildMap, $prevEval, $jobOutPathMap, $plugins);
+        my @jobsWithConstituents;
+
+        while (defined(my $job = $jobsIter->())) {
+            if ($jobsetsJobset) {
+                die "The .jobsets jobset must only have a single job named 'jobsets'"
+                    unless $job->{attr} eq "jobsets";
+            }
+
+            $evaluationErrorMsg .=
+                ($job->{attr} ne "" ? "in job ‘$job->{attr}’" : "at top-level") .
+                ":\n" . $job->{error} . "\n\n" if defined $job->{error};
+
+            checkBuild($db, $jobset, $ev, $inputInfo, $job, \%buildMap, $prevEval, $jobOutPathMap, $plugins)
+                unless defined $job->{error};
+
+            if (defined $job->{constituents}) {
+                push @jobsWithConstituents, $job;
+            }
         }
 
         # Have any builds been added or removed since last time?
@@ -801,21 +849,20 @@ sub checkJobsetWrapped {
                 $drvPathToId{$x->{drvPath}} = $x;
             }
 
-            foreach my $job (values %{$jobs}) {
-                next unless $job->{constituents};
-
+            foreach my $job (values @jobsWithConstituents) {
+                next unless defined $job->{constituents};
                 if (defined $job->{error}) {
-                    die "aggregate job ‘$job->{jobName}’ failed with the error: $job->{error}\n";
+                    die "aggregate job ‘$job->{attr}’ failed with the error: $job->{error}\n";
                 }
 
                 my $x = $drvPathToId{$job->{drvPath}} or
-                    die "aggregate job ‘$job->{jobName}’ has no corresponding build record.\n";
+                    die "aggregate job ‘$job->{attr}’ has no corresponding build record.\n";
                 foreach my $drvPath (@{$job->{constituents}}) {
                     my $constituent = $drvPathToId{$drvPath};
                     if (defined $constituent) {
                         $db->resultset('AggregateConstituents')->update_or_create({aggregate => $x->{id}, constituent => $constituent->{id}});
                     } else {
-                        warn "aggregate job ‘$job->{jobName}’ has a constituent ‘$drvPath’ that doesn't correspond to a Hydra build\n";
+                        warn "aggregate job ‘$job->{attr}’ has a constituent ‘$drvPath’ that doesn't correspond to a Hydra build\n";
                     }
                 }
             }
@@ -857,11 +904,15 @@ sub checkJobsetWrapped {
         $jobset->update({ enabled => 0 }) if $jobset->enabled == 2;
 
         $jobset->update({ lastcheckedtime => time, forceeval => undef });
+
+        $evaluationErrorRecord->update({ errormsg => $evaluationErrorMsg });
+        setJobsetError($jobset, $evaluationErrorMsg, $evaluationErrorTime);
+
+        $evalStop = clock_gettime(CLOCK_MONOTONIC);
+        $ev->update({ evaltime => abs(int($evalStop - $evalStart)) });
     });
 
-    my $dbStop = clock_gettime(CLOCK_MONOTONIC);
-
-    Net::Statsd::timing("hydra.evaluator.db_time", int(($dbStop - $dbStart) * 1000));
+    Net::Statsd::timing("hydra.evaluator.eval_time", int(($evalStop - $evalStart) * 1000));
     Net::Statsd::increment("hydra.evaluator.evals");
     Net::Statsd::increment("hydra.evaluator.cached_evals") unless $jobsetChanged;
 }

t/Hydra/Controller/Jobset/evals.t

@@ -32,4 +32,9 @@ subtest "/jobset/PROJECT/JOBSET/evals" => sub {
     ok($jobsetevals->is_success, "The page showing the jobset evals returns 200.");
 };
 
+subtest "/jobset/PROJECT/JOBSET/errors" => sub {
+    my $jobsetevals = request(GET '/jobset/' . $project->name . '/' . $jobset->name . '/errors');
+    ok($jobsetevals->is_success, "The page showing the jobset eval errors returns 200.");
+};
+
 done_testing;

t/Hydra/Controller/JobsetEval/fetch.t

@@ -35,6 +35,10 @@ subtest "Fetching the eval's overview" => sub {
     is($fetch->code, 200, "channel page is 200");
 };
 
+subtest "Fetching the eval's overview" => sub {
+    my $fetch = request(GET '/eval/' . $eval->id, '/errors');
+    is($fetch->code, 200, "errors page is 200");
+};
 
 
 done_testing;

t/evaluator/evaluate-constituents-broken.t

@@ -18,14 +18,14 @@ isnt($res, 0, "hydra-eval-jobset exits non-zero");
 ok(utf8::decode($stderr), "Stderr output is UTF8-clean");
 like(
     $stderr,
-    qr/aggregate job ‘mixed_aggregate’ failed with the error: constituentA: does not exist/,
+    qr/aggregate job ‘mixed_aggregate’ failed with the error: "constituentA": does not exist/,
     "The stderr record includes a relevant error message"
 );
 
-$jobset->discard_changes;  # refresh from DB
+$jobset->discard_changes({ '+columns' => {'errormsg' => 'errormsg'} });  # refresh from DB
 like(
     $jobset->errormsg,
-    qr/aggregate job ‘mixed_aggregate’ failed with the error: constituentA: does not exist/,
+    qr/aggregate job ‘mixed_aggregate’ failed with the error: "constituentA": does not exist/,
     "The jobset records a relevant error message"
 );
 

t/evaluator/evaluate-constituents-gc.t

@@ -5,13 +5,58 @@ use Test2::V0;
 
 my $ctx = test_context();
 
-my $builds = $ctx->makeAndEvaluateJobset(
-    expression => 'constituents.nix',
+my $expression = 'constituents.nix';
+my $jobsetCtx = $ctx->makeJobset(
+    expression => $expression,
+);
+my $builds = $ctx->evaluateJobset(
+    jobset => $jobsetCtx->{"jobset"},
+    expression => $expression,
+    build => 0,
 );
 
 my $constituentA = $builds->{"constituentA"};
 my $directAggregate = $builds->{"direct_aggregate"};
 my $indirectAggregate = $builds->{"indirect_aggregate"};
+my $mixedAggregate = $builds->{"mixed_aggregate"};
+
+# Ensure that we get exactly the aggregates we expect
+my %expected_constituents = (
+    'direct_aggregate' => {
+        'constituentA' => 1,
+    },
+    'indirect_aggregate' => {
+        'constituentA' => 1,
+    },
+    'mixed_aggregate' => {
+        # Note that `constituentA_alias` becomes `constituentA`, because
+        # the shorter name is preferred
+        'constituentA' => 1,
+        'constituentB' => 1,
+    },
+);
+
+my $rs = $ctx->db->resultset('AggregateConstituents')->search(
+    {},
+    {
+        join     => [ 'aggregate', 'constituent' ],  # Use correct relationship names
+        columns  => [],
+        '+select' => [ 'aggregate.job', 'constituent.job' ],
+        '+as'     => [ 'aggregate_job', 'constituent_job' ],
+    }
+);
+
+my %actual_constituents;
+while (my $row = $rs->next) {
+    my $aggregate_job   = $row->get_column('aggregate_job');
+    my $constituent_job = $row->get_column('constituent_job');
+    $actual_constituents{$aggregate_job} //= {};
+    $actual_constituents{$aggregate_job}{$constituent_job} = 1;
+}
+
+is(\%actual_constituents, \%expected_constituents, "Exact aggregate constituents as expected");
+
+# Check that deletion also doesn't work accordingly
 
 is(system('nix-store', '--delete', $constituentA->drvpath), 256, "Deleting a constituent derivation fails");
 is(system('nix-store', '--delete', $directAggregate->drvpath), 256, "Deleting the direct aggregate derivation fails");

t/evaluator/evaluate-flake.t

@@ -0,0 +1,67 @@
+use feature 'unicode_strings';
+use strict;
+use warnings;
+use Setup;
+use Test2::V0;
+use File::Copy qw(cp);
+
+my $ctx = test_context(
+    nix_config => qq|
+    experimental-features = nix-command flakes
+    |,
+    hydra_config => q|
+    <runcommand>
+      evaluator_pure_eval = false
+    </runcommand>
+    |
+);
+
+sub checkFlake {
+    my ($flake) = @_;
+
+    cp($ctx->jobsdir . "/basic.nix", $ctx->jobsdir . "/" . $flake);
+    cp($ctx->jobsdir . "/config.nix", $ctx->jobsdir . "/" . $flake);
+    cp($ctx->jobsdir . "/empty-dir-builder.sh", $ctx->jobsdir . "/" . $flake);
+    cp($ctx->jobsdir . "/fail.sh", $ctx->jobsdir . "/" . $flake);
+    cp($ctx->jobsdir . "/succeed-with-failed.sh", $ctx->jobsdir . "/" . $flake);
+
+    chmod 0755, $ctx->jobsdir . "/" . $flake . "/empty-dir-builder.sh";
+    chmod 0755, $ctx->jobsdir . "/" . $flake . "/fail.sh";
+    chmod 0755, $ctx->jobsdir . "/" . $flake . "/succeed-with-failed.sh";
+
+    my $builds = $ctx->makeAndEvaluateJobset(
+        flake => 'path:' . $ctx->jobsdir . "/" . $flake,
+        build => 1
+    );
+
+    subtest "Build: succeed_with_failed" => sub {
+        my $build = $builds->{"succeed_with_failed"};
+
+        is($build->finished, 1, "Build should be finished.");
+        is($build->buildstatus, 6, "succeeeded-but-failed should have buildstatus 6.");
+    };
+
+    subtest "Build: empty_dir" => sub {
+        my $build = $builds->{"empty_dir"};
+
+        is($build->finished, 1, "Build should be finished.");
+        is($build->buildstatus, 0, "Should have succeeded.");
+    };
+
+    subtest "Build: fails" => sub {
+        my $build = $builds->{"fails"};
+
+        is($build->finished, 1, "Build should be finished.");
+        is($build->buildstatus, 1, "Should have failed.");
+    };
+}
+
+subtest "Flake using `checks`" => sub {
+    checkFlake 'flake-checks'
+};
+
+subtest "Flake using `hydraJobs`" => sub {
+    checkFlake 'flake-hydraJobs'
+};
+
+done_testing;

t/evaluator/evaluate-meta.t

@@ -0,0 +1,22 @@
+use feature 'unicode_strings';
+use strict;
+use warnings;
+use Setup;
+use Test2::V0;
+
+my $ctx = test_context();
+
+my $builds = $ctx->makeAndEvaluateJobset(
+    expression => "meta.nix",
+    build => 1
+);
+
+my $build = $builds->{"full-of-meta"};
+
+is($build->finished, 1, "Build should be finished.");
+is($build->description, "This is the description of the job.", "Wrong description extracted from the build.");
+is($build->license, "MIT, BSD", "Wrong licenses extracted from the build.");
+is($build->homepage, "https://example.com/", "Wrong homepage extracted from the build.");
+is($build->maintainers, 'alice@example.com, bob@not.found', "Wrong maintainers extracted from the build.");
+
+done_testing;

t/jobs/constituents.nix

@@ -5,6 +5,8 @@ rec {
     builder = ./empty-dir-builder.sh;
   };
 
+  constituentA_alias = constituentA;
+
   constituentB = mkDerivation {
     name = "empty-dir-B";
     builder = ./empty-dir-builder.sh;
@@ -32,7 +34,7 @@ rec {
     name = "mixed_aggregate";
     _hydraAggregate = true;
     constituents = [
-      "constituentA"
+      "constituentA_alias"
       constituentB
     ];
     builder = ./empty-dir-builder.sh;

t/jobs/flake-checks/flake.nix

@@ -0,0 +1,6 @@
+{
+  outputs = { ... }: {
+    checks =
+      import ./basic.nix;
+  };
+}

t/jobs/flake-hydraJobs/flake.nix

@@ -0,0 +1,6 @@
+{
+  outputs = { ... }: {
+    hydraJobs =
+      import ./basic.nix;
+  };
+}

t/jobs/meta.nix

@@ -0,0 +1,17 @@
+with import ./config.nix;
+{
+  full-of-meta =
+    mkDerivation {
+      name = "full-of-meta";
+      builder = ./empty-dir-builder.sh;
+
+      meta = {
+        description = "This is the description of the job.";
+        license = [ { shortName = "MIT"; } "BSD" ];
+        homepage = "https://example.com/";
+        maintainers = [ "alice@example.com" { email = "bob@not.found"; } ];
+
+        outPath = "${placeholder "out"}";
+      };
+    };
+}

t/lib/CliRunners.pm

@@ -14,7 +14,7 @@ our @EXPORT = qw(
 sub evalSucceeds {
     my ($jobset) = @_;
     my ($res, $stdout, $stderr) = captureStdoutStderr(60, ("hydra-eval-jobset", $jobset->project->name, $jobset->name));
-    $jobset->discard_changes;  # refresh from DB
+    $jobset->discard_changes({ '+columns' => {'errormsg' => 'errormsg'} });  # refresh from DB
     if ($res) {
         chomp $stdout; chomp $stderr;
         utf8::decode($stdout) or die "Invalid unicode in stdout.";
@@ -29,7 +29,7 @@ sub evalSucceeds {
 sub evalFails {
     my ($jobset) = @_;
     my ($res, $stdout, $stderr) = captureStdoutStderr(60, ("hydra-eval-jobset", $jobset->project->name, $jobset->name));
-    $jobset->discard_changes;  # refresh from DB
+    $jobset->discard_changes({ '+columns' => {'errormsg' => 'errormsg'} });  # refresh from DB
     if (!$res) {
         chomp $stdout; chomp $stderr;
         utf8::decode($stdout) or die "Invalid unicode in stdout.";

t/lib/HydraTestContext.pm

@@ -165,20 +165,46 @@ sub nix_state_dir {
 sub makeAndEvaluateJobset {
     my ($self, %opts) = @_;
 
-    my $expression = $opts{'expression'} || die "Mandatory 'expression' option not passed to makeAndEvaluateJobset.\n";
-    my $jobsdir = $opts{'jobsdir'} // $self->jobsdir;
-    my $should_build = $opts{'build'} // 0;
+    my $expression = $opts{'expression'};
+    my $flake = $opts{'flake'};
+    if (not $expression and not $flake) {
+        die "One of 'expression' or 'flake' must be passed to makeEvaluateJobset.\n";
+    }
 
-    my $jobsetCtx = $self->makeJobset(
-        expression => $expression,
+    my $jobsdir = $opts{'jobsdir'} // $self->jobsdir;
+
+    my %args = (
         jobsdir => $jobsdir,
     );
-    my $jobset = $jobsetCtx->{"jobset"};
+    if ($expression) {
+        $args{expression} = $expression;
+    }
+    if ($flake) {
+        $args{flake} = $flake;
+    }
+    my $jobsetCtx = $self->makeJobset(%args);
+
+    return $self->evaluateJobset(
+        jobset => $jobsetCtx->{"jobset"},
+        expression => $expression,
+        flake => $flake,
+        build => $opts{"build"} // 0,
+    )
+}
+
+sub evaluateJobset {
+    my ($self, %opts) = @_;
+
+    my $jobset = $opts{'jobset'};
+
+    my $expression = $opts{'expression'} // $opts{'flake'};
 
     evalSucceeds($jobset) or die "Evaluating jobs/$expression should exit with return code 0.\n";
 
     my $builds = {};
 
+    my $should_build = $opts{'build'};
+
     for my $build ($jobset->builds) {
         if ($should_build) {
             runBuild($build) or die "Build '".$build->job."' from jobs/$expression should exit with return code 0.\n";
@@ -195,7 +221,7 @@ sub makeAndEvaluateJobset {
 #
 # In return, you get a hash of the user, project, and jobset records.
 #
-# This always uses an `expression` from the `jobsdir` directory.
+# This always uses an `expression` or `flake` from the `jobsdir` directory.
 #
 # Hash Parameters:
 #
@@ -204,7 +230,12 @@ sub makeAndEvaluateJobset {
 sub makeJobset {
     my ($self, %opts) = @_;
 
-    my $expression = $opts{'expression'} || die "Mandatory 'expression' option not passed to makeJobset.\n";
+    my $expression = $opts{'expression'};
+    my $flake = $opts{'flake'};
+    if (not $expression and not $flake) {
+        die "One of 'expression' or 'flake' must be passed to makeJobset.\n";
+    }
+
     my $jobsdir = $opts{'jobsdir'} // $self->jobsdir;
 
     # Create a new user for this test
@@ -222,12 +253,20 @@ sub makeJobset {
     });
 
     # Create a new jobset for this test and set up the inputs
-    my $jobset = $project->jobsets->create({
+    my %args = (
         name => rand_chars(),
-        nixexprinput => "jobs",
-        nixexprpath => $expression,
         emailoverride => ""
-    });
+    );
+    if ($expression) {
+        $args{type} = 0;
+        $args{nixexprinput} = "jobs";
+        $args{nixexprpath} = $expression;
+    }
+    if ($flake) {
+        $args{type} = 1;
+        $args{flake} = $flake;
+    }
+    my $jobset = $project->jobsets->create(\%args);
     my $jobsetinput = $jobset->jobsetinputs->create({name => "jobs", type => "path"});
     $jobsetinput->jobsetinputalts->create({altnr => 0, value => $jobsdir});
 

t/meson.build

@@ -27,7 +27,6 @@ testenv.prepend('PERL5LIB',
   separator: ':'
 )
 testenv.prepend('PATH',
-  fs.parent(hydra_eval_jobs.full_path()),
   fs.parent(hydra_evaluator.full_path()),
   fs.parent(hydra_queue_runner.full_path()),
   meson.project_source_root() / 'src/script',

t/queue-runner/constituents.t

@@ -22,11 +22,11 @@ is(nrQueuedBuildsForJobset($jobset), 0, "Evaluating jobs/broken-constituent.nix
 
 like(
     $jobset->errormsg,
-    qr/^does-not-exist: does not exist$/m,
+    qr/^"does-not-exist": does not exist$/m,
     "Evaluating jobs/broken-constituent.nix should log an error for does-not-exist");
 like(
     $jobset->errormsg,
-    qr/^does-not-evaluate: error: assertion 'false' failed$/m,
+    qr/^"does-not-evaluate": "error: assertion 'false' failed/m,
     "Evaluating jobs/broken-constituent.nix should log an error for does-not-evaluate");
 
 done_testing;

t/queue-runner/direct-indirect-constituents.t

@@ -13,7 +13,7 @@ my $constituentBuildA = $builds->{"constituentA"};
 my $constituentBuildB = $builds->{"constituentB"};
 
 my $eval = $constituentBuildA->jobsetevals->first();
-is($eval->evaluationerror->errormsg, "");
+is($eval->evaluationerror->has_error, 0);
 
 subtest "Verifying the direct aggregate" => sub {
     my $aggBuild = $builds->{"direct_aggregate"};