WIP rework goals

src/libstore/build/build-trace-goal.cc

@@ -0,0 +1,208 @@
+#include "nix/store/build/build-trace-goal.hh"
+#include "nix/util/finally.hh"
+#include "nix/store/build/worker.hh"
+#include "nix/store/build/substitution-goal.hh"
+#include "nix/util/callback.hh"
+#include "nix/util/util.hh"
+#include "nix/store/derivations.hh"
+#include "nix/store/store-open.hh"
+#include "nix/store/build/derivation-resolution-goal.hh"
+
+namespace nix {
+
+BuildTraceGoal::BuildTraceGoal(const SingleDerivedPath::Built & id, Worker & worker)
+    : Goal{worker, init()}
+    , id{id}
+{
+    name = fmt("substitution of '%s'", id.to_string(worker.store));
+    trace("created");
+}
+
+Goal::Co BuildTraceGoal::init()
+{
+    trace("init");
+
+    DrvOutput id2{
+        .drvPath = StorePath::dummy,
+        .outputName = id.output,
+    };
+
+    // No `std::visit` with coroutines :(
+    if (const auto * path = std::get_if<SingleDerivedPath::Opaque>(&*id.drvPath)) {
+        // At least we know the drv path statically, can procede
+        id2.drvPath = path->path;
+    } else if (const auto * outputDeriving = std::get_if<SingleDerivedPath::Built>(&*id.drvPath)) {
+        // Dynamic derivation case, need to resolve that first.
+
+        auto g = worker.makeBuildTraceGoal({
+            outputDeriving->drvPath,
+            outputDeriving->output,
+        });
+
+        co_await await(Goals{upcast_goal(g)});
+
+        if (nrFailed > 0) {
+            debug("The output deriving path '%s' could not be resolved", outputDeriving->to_string(worker.store));
+            co_return amDone(nrNoSubstituters > 0 ? ecNoSubstituters : ecFailed);
+        }
+
+        id2.drvPath = g->outputInfo->outPath;
+    }
+
+    /* If the derivation already exists, we’re done */
+    if ((outputInfo = worker.store.queryRealisation(id2))) {
+        co_return amDone(ecSuccess);
+    }
+
+    /**
+     * Firstly, whether we know the status, secondly, what it is
+     */
+    std::optional<bool> drvIsResolved;
+
+    /* If the derivation has statically-known output paths */
+    if (worker.evalStore.isValidPath(id2.drvPath)) {
+        auto drv = worker.evalStore.readDerivation(id2.drvPath);
+        auto os = drv.outputsAndOptPaths(worker.store);
+        /* Mark what we now know */
+        drvIsResolved = {drv.inputDrvs.map.empty()};
+        if (auto * p = get(os, id2.outputName)) {
+            if (auto & outPath = p->second) {
+                outputInfo = std::make_shared<UnkeyedRealisation>(*outPath);
+                co_return amDone(ecSuccess);
+            } else {
+                /* Otherwise, not failure, just looking up build trace below. */
+            }
+        } else {
+            debug(
+                "Derivation '%s' does not have output '%s', impossible to find build trace key-value pair",
+                worker.store.printStorePath(id2.drvPath),
+                id2.outputName);
+            co_return amDone(ecFailed);
+        }
+    }
+
+    auto subs = settings.useSubstitutes ? getDefaultSubstituters() : std::list<ref<Store>>();
+
+    bool substituterFailed = false;
+
+    if (!drvIsResolved || *drvIsResolved) {
+        /* Since derivation might be resolved --- isn't known to be
+           not-resolved, it might have entries. So, let's try querying
+           the substituters. */
+        for (const auto & sub : subs) {
+            trace("trying next substituter");
+
+            /* The callback of the curl download below can outlive `this` (if
+               some other error occurs), so it must not touch `this`. So put
+               the shared state in a separate refcounted object. */
+            auto outPipe = std::make_shared<MuxablePipe>();
+#ifndef _WIN32
+            outPipe->create();
+#else
+            outPipe->createAsyncPipe(worker.ioport.get());
+#endif
+
+            auto promise = std::make_shared<std::promise<std::shared_ptr<const UnkeyedRealisation>>>();
+
+            sub->queryRealisation(
+                id2, {[outPipe(outPipe), promise(promise)](std::future<std::shared_ptr<const UnkeyedRealisation>> res) {
+                    try {
+                        Finally updateStats([&]() { outPipe->writeSide.close(); });
+                        promise->set_value(res.get());
+                    } catch (...) {
+                        promise->set_exception(std::current_exception());
+                    }
+                }});
+
+            worker.childStarted(
+                shared_from_this(),
+                {
+#ifndef _WIN32
+                    outPipe->readSide.get()
+#else
+                    &*outPipe
+#endif
+                },
+                true,
+                false);
+
+            co_await Suspend{};
+
+            worker.childTerminated(this);
+
+            std::shared_ptr<const UnkeyedRealisation> outputInfo;
+            try {
+                outputInfo = promise->get_future().get();
+            } catch (std::exception & e) {
+                printError(e.what());
+                substituterFailed = true;
+            }
+
+            if (!outputInfo)
+                continue;
+
+            worker.store.registerDrvOutput({*outputInfo, id2});
+
+            trace("finished");
+            co_return amDone(ecSuccess);
+        }
+    }
+
+    /* Derivation might not be resolved, let's try doing that */
+    trace("trying resolving derivation in build-trace goal");
+
+    auto g = worker.makeDerivationResolutionGoal(id2.drvPath);
+
+    co_await await(Goals{g});
+
+    if (nrFailed > 0) {
+        /* None left.  Terminate this goal and let someone else deal
+           with it. */
+        debug(
+            "derivation output '%s' is required, but there is no substituter that can provide it",
+            id2.render(worker.store));
+
+        if (substituterFailed) {
+            worker.failedSubstitutions++;
+            worker.updateProgress();
+        }
+
+        /* Hack: don't indicate failure if there were no substituters.
+           In that case the calling derivation should just do a
+           build. */
+        co_return amDone(substituterFailed ? ecFailed : ecNoSubstituters);
+    }
+
+    /* This should be set if the goal succeeded */
+    assert(g->resolvedDrv);
+
+    /* Try everything again, now with a resolved derivation */
+    auto bt2 = worker.makeBuildTraceGoal({
+        makeConstantStorePathRef(g->resolvedDrvPath),
+        id2.outputName,
+    });
+
+    co_await await(Goals{bt2});
+
+    /* Set the build trace value as our own. Note the signure will not
+       match our key since we're the unresolved derivation, but that's
+       fine. We're not writing it to the DB; that's `bt2`' job. */
+    if (bt2->outputInfo)
+        outputInfo = bt2->outputInfo;
+
+    co_return amDone(bt2->exitCode, bt2->ex);
+}
+
+std::string BuildTraceGoal::key()
+{
+    /* "a$" ensures substitution goals happen before derivation
+       goals. */
+    return "a$" + std::string(id.to_string(worker.store));
+}
+
+void BuildTraceGoal::handleEOF(Descriptor fd)
+{
+    worker.wakeUp(shared_from_this());
+}
+
+}

src/libstore/build/derivation-creation-and-realisation-goal.cc

@@ -62,7 +62,7 @@ std::string DerivationCreationAndRealisationGoal::key()
        i.e. a derivation named "aardvark" always comes before "baboon". And
        substitution goals and inner derivation goals always happen before
        derivation goals (due to "b$"). */
-    return "c$" + std::string(pathPartOfReq(*drvReq).name()) + "$" + DerivedPath::Built{
+    return "d$" + std::string(pathPartOfReq(*drvReq).name()) + "$" + DerivedPath::Built{
         .drvPath = drvReq,
         .outputs = wantedOutputs,
     }.to_string(worker.store);

src/libstore/build/derivation-goal.cc

@@ -50,7 +50,7 @@ std::string DerivationGoal::key()
        i.e. a derivation named "aardvark" always comes before
        "baboon". And substitution goals always happen before
        derivation goals (due to "b$"). */
-    return "b$" + std::string(drvPath.name()) + "$" + SingleDerivedPath::Built{
+    return "c$" + std::string(drvPath.name()) + "$" + SingleDerivedPath::Built{
         .drvPath = makeConstantStorePathRef(drvPath),
         .output = wantedOutput,
     }.to_string(worker.store);

src/libstore/build/derivation-resolution-goal.cc

@@ -0,0 +1,82 @@
+#include "nix/store/build/derivation-resolution-goal.hh"
+#include "nix/util/finally.hh"
+#include "nix/store/build/worker.hh"
+#include "nix/store/build/substitution-goal.hh"
+#include "nix/util/callback.hh"
+#include "nix/store/derivations.hh"
+
+namespace nix {
+
+DerivationResolutionGoal::DerivationResolutionGoal(const StorePath & drvPath, Worker & worker)
+    : Goal(worker, init())
+    , drvPath(drvPath)
+{
+    name = fmt("resolution of '%s'", worker.store.printStorePath(drvPath));
+    trace("created");
+}
+
+Goal::Co DerivationResolutionGoal::init()
+{
+    trace("init");
+
+    std::unique_ptr<Derivation> drv;
+
+    if (worker.evalStore.isValidPath(drvPath)) {
+        drv = std::make_unique<Derivation>(worker.evalStore.readDerivation(drvPath));
+    } else if (worker.store.isValidPath(drvPath)) {
+        drv = std::make_unique<Derivation>(worker.store.readDerivation(drvPath));
+    } else {
+        auto goal0 = worker.makePathSubstitutionGoal(drvPath);
+        goal0->preserveException = true;
+        co_await await(Goals{goal0});
+        if (nrFailed > 0)
+            co_return amDone(goal0->exitCode, goal0->ex);
+
+        drv = std::make_unique<Derivation>(worker.store.readDerivation(drvPath));
+    }
+
+    trace("output path substituted");
+
+    std::set<std::shared_ptr<BuildTraceGoal>> goals;
+
+    std::function<void(ref<SingleDerivedPath>, const DerivedPathMap<StringSet>::ChildNode &)> accumInputPaths;
+
+    accumInputPaths = [&](ref<SingleDerivedPath> depDrvPath, const DerivedPathMap<StringSet>::ChildNode & inputNode) {
+        for (auto & outputName : inputNode.value)
+            goals.insert(worker.makeBuildTraceGoal(SingleDerivedPath::Built{depDrvPath, outputName}));
+
+        for (auto & [outputName, childNode] : inputNode.childMap)
+            accumInputPaths(make_ref<SingleDerivedPath>(SingleDerivedPath::Built{depDrvPath, outputName}), childNode);
+    };
+
+    for (auto & [depDrvPath, depNode] : drv->inputDrvs.map)
+        accumInputPaths(makeConstantStorePathRef(depDrvPath), depNode);
+
+    if (nrFailed > 0) {
+        debug("TODO message");
+        co_return amDone(nrNoSubstituters > 0 ? ecNoSubstituters : ecFailed);
+    }
+
+    if (true /*auto d = drv.tryResolve(....)*/) {
+        //resolvedDerivation = d.take();
+
+        trace("finished");
+        co_return amDone(ecSuccess);
+    } else {
+        // fail
+    }
+}
+
+std::string DerivationResolutionGoal::key()
+{
+    /* "a$" ensures substitution goals happen before derivation
+       goals. */
+    return "b$" + worker.store.printStorePath(drvPath);
+}
+
+void DerivationResolutionGoal::handleEOF(Descriptor fd)
+{
+    worker.wakeUp(shared_from_this());
+}
+
+}

src/libstore/build/drv-output-substitution-goal.cc

@@ -3,7 +3,7 @@
 #include "nix/store/build/worker.hh"
 #include "nix/store/build/substitution-goal.hh"
 #include "nix/util/callback.hh"
-#include "nix/store/store-open.hh"
+#include "nix/store/build/build-trace-goal.hh"
 
 namespace nix {
 
@@ -20,101 +20,32 @@ Goal::Co DrvOutputSubstitutionGoal::init()
 {
     trace("init");
 
-    /* If the derivation already exists, we’re done */
-    if (worker.store.queryRealisation(id)) {
-        co_return amDone(ecSuccess);
+    auto goal0 = worker.makeBuildTraceGoal({
+        makeConstantStorePathRef(id.drvPath),
+        id.outputName,
+    });
+    co_await await(Goals{upcast_goal(goal0)});
+
+    trace("output path substituted");
+
+    if (nrFailed > 0) {
+        debug("The output path of the derivation output '%s' could not be substituted", id.render(worker.store));
+        co_return amDone(nrNoSubstituters > 0 ? ecNoSubstituters : ecFailed);
     }
 
-    auto subs = settings.useSubstitutes ? getDefaultSubstituters() : std::list<ref<Store>>();
+    auto goal1 = worker.makePathSubstitutionGoal(goal0->outputInfo->outPath);
+    goal0.reset();
 
-    bool substituterFailed = false;
-
-    for (const auto & sub : subs) {
-        trace("trying next substituter");
-
-        /* The callback of the curl download below can outlive `this` (if
-           some other error occurs), so it must not touch `this`. So put
-           the shared state in a separate refcounted object. */
-        auto outPipe = std::make_shared<MuxablePipe>();
-#ifndef _WIN32
-        outPipe->create();
-#else
-        outPipe->createAsyncPipe(worker.ioport.get());
-#endif
-
-        auto promise = std::make_shared<std::promise<std::shared_ptr<const UnkeyedRealisation>>>();
-
-        sub->queryRealisation(
-            id, {[outPipe(outPipe), promise(promise)](std::future<std::shared_ptr<const UnkeyedRealisation>> res) {
-                try {
-                    Finally updateStats([&]() { outPipe->writeSide.close(); });
-                    promise->set_value(res.get());
-                } catch (...) {
-                    promise->set_exception(std::current_exception());
-                }
-            }});
-
-        worker.childStarted(
-            shared_from_this(),
-            {
-#ifndef _WIN32
-                outPipe->readSide.get()
-#else
-                &*outPipe
-#endif
-            },
-            true,
-            false);
-
-        co_await Suspend{};
-
-        worker.childTerminated(this);
-
-        try {
-            outputInfo = promise->get_future().get();
-        } catch (std::exception & e) {
-            printError(e.what());
-            substituterFailed = true;
-        }
-
-        if (!outputInfo)
-            continue;
-
-        co_await await(Goals{worker.makePathSubstitutionGoal(outputInfo->outPath)});
-
-        trace("output path substituted");
-
-        if (nrFailed > 0) {
-            debug("The output path of the derivation output '%s' could not be substituted", id.render(worker.store));
-            co_return amDone(nrNoSubstituters > 0 ? ecNoSubstituters : ecFailed);
-        }
-
-        worker.store.registerDrvOutput({*outputInfo, id});
-
-        trace("finished");
-        co_return amDone(ecSuccess);
-    }
-
-    /* None left.  Terminate this goal and let someone else deal
-       with it. */
-    debug("derivation output '%s' is required, but there is no substituter that can provide it", id.render(worker.store));
-
-    if (substituterFailed) {
-        worker.failedSubstitutions++;
-        worker.updateProgress();
-    }
-
-    /* Hack: don't indicate failure if there were no substituters.
-       In that case the calling derivation should just do a
-       build. */
-    co_return amDone(substituterFailed ? ecFailed : ecNoSubstituters);
+    goal1->preserveException = true;
+    co_await await(Goals{upcast_goal(goal1)});
+    co_return amDone(goal1->exitCode, goal1->ex);
 }
 
 std::string DrvOutputSubstitutionGoal::key()
 {
     /* "a$" ensures substitution goals happen before derivation
        goals. */
-    return "a$" + std::string(id.render(worker.store));
+    return "b$" + std::string(id.render(worker.store));
 }
 
 void DrvOutputSubstitutionGoal::handleEOF(Descriptor fd)

src/libstore/build/worker.cc

@@ -9,6 +9,8 @@
 #ifndef _WIN32 // TODO Enable building on Windows
 #  include "nix/store/build/hook-instance.hh"
 #endif
+#include "nix/store/build/build-trace-goal.hh"
+#include "nix/store/build/derivation-resolution-goal.hh"
 #include "nix/util/signals.hh"
 
 namespace nix {
@@ -103,6 +105,33 @@ std::shared_ptr<DrvOutputSubstitutionGoal> Worker::makeDrvOutputSubstitutionGoal
 }
 
 
+std::shared_ptr<BuildTraceGoal> Worker::makeBuildTraceGoal(
+    const SingleDerivedPath::Built & req)
+{
+    std::weak_ptr<BuildTraceGoal> & goal_weak = buildTraceGoals.ensureSlot(req).value;
+    std::shared_ptr<BuildTraceGoal> goal = goal_weak.lock();
+    if (!goal) {
+        goal = std::make_shared<BuildTraceGoal>(req, *this);
+        goal_weak = goal;
+        wakeUp(goal);
+    }
+    return goal;
+}
+
+
+std::shared_ptr<DerivationResolutionGoal> Worker::makeDerivationResolutionGoal(const StorePath & drvPath)
+{
+    std::weak_ptr<DerivationResolutionGoal> & goal_weak = derivationResolutionGoals[drvPath];
+    auto goal = goal_weak.lock(); // FIXME
+    if (!goal) {
+        goal = std::make_shared<DerivationResolutionGoal>(drvPath, *this);
+        goal_weak = goal;
+        wakeUp(goal);
+    }
+    return goal;
+}
+
+
 GoalPtr Worker::makeGoal(const DerivedPath & req, BuildMode buildMode)
 {
     return std::visit(overloaded {
@@ -576,4 +605,14 @@ GoalPtr upcast_goal(std::shared_ptr<DerivationGoal> subGoal)
     return subGoal;
 }
 
+GoalPtr upcast_goal(std::shared_ptr<BuildTraceGoal> subGoal)
+{
+    return subGoal;
+}
+
+GoalPtr upcast_goal(std::shared_ptr<DerivationResolutionGoal> subGoal)
+{
+    return subGoal;
+}
+
 }

src/libstore/ca-specific-schema.sql

@@ -8,7 +8,11 @@ create table if not exists Realisations (
     outputName text not null, -- symbolic output id, usually "out"
     outputPath integer not null,
     signatures text, -- space-separated list
-    foreign key (outputPath) references ValidPaths(id) on delete cascade
+
+    -- No such foreign key because we may well want realisations for
+    -- garbage-collected dependencies
+
+    --foreign key (outputPath) references ValidPaths(id) on delete cascade
 );
 
 create index if not exists IndexRealisations on Realisations(drvPath, outputName);

src/libstore/derived-path-map.cc

@@ -52,7 +52,9 @@ typename DerivedPathMap<V>::ChildNode * DerivedPathMap<V>::findSlot(const Single
 
 // instantiations
 
+#include "nix/store/build/build-trace-goal.hh"
 #include "nix/store/build/derivation-creation-and-realisation-goal.hh"
+
 namespace nix {
 
 template<>
@@ -69,7 +71,7 @@ std::strong_ordering DerivedPathMap<StringSet>::ChildNode::operator <=> (
 template struct DerivedPathMap<StringSet>::ChildNode;
 template struct DerivedPathMap<StringSet>;
 
+template struct DerivedPathMap<std::weak_ptr<BuildTraceGoal>>;
 template struct DerivedPathMap<std::map<OutputsSpec, std::weak_ptr<DerivationCreationAndRealisationGoal>>>;
 
-
 };

src/libstore/include/nix/store/build/build-trace-goal.hh

@@ -0,0 +1,54 @@
+#pragma once
+///@file
+
+#include <thread>
+#include <future>
+
+#include "nix/store/store-api.hh"
+#include "nix/store/build/goal.hh"
+#include "nix/store/realisation.hh"
+#include "nix/util/muxable-pipe.hh"
+
+namespace nix {
+
+class Worker;
+
+/**
+ * Try to recursively obtain build trace key-value pairs in order to
+ * resolve the given output deriving path.
+ */
+class BuildTraceGoal : public Goal
+{
+
+    /**
+     * The output derivation path we're trying to reasolve.
+     */
+    SingleDerivedPath::Built id;
+
+public:
+    BuildTraceGoal(const SingleDerivedPath::Built & id, Worker & worker);
+
+    /**
+     * The realisation corresponding to the given output id.
+     * Will be filled once we can get it.
+     */
+    std::shared_ptr<const UnkeyedRealisation> outputInfo;
+
+    Co init();
+
+    void timedOut(Error && ex) override
+    {
+        unreachable();
+    };
+
+    std::string key() override;
+
+    void handleEOF(Descriptor fd) override;
+
+    JobCategory jobCategory() const override
+    {
+        return JobCategory::Substitution;
+    };
+};
+
+}

src/libstore/include/nix/store/build/derivation-resolution-goal.hh

@@ -0,0 +1,60 @@
+#pragma once
+///@file
+
+#include <thread>
+#include <future>
+
+#include "nix/store/store-api.hh"
+#include "nix/store/build/goal.hh"
+#include "nix/store/realisation.hh"
+#include "nix/util/muxable-pipe.hh"
+
+namespace nix {
+
+class Worker;
+
+/**
+ * The purpose of this is to resolve the given derivation, so that it
+ * only has constant deriving paths as inputs.
+ */
+class DerivationResolutionGoal : public Goal
+{
+
+    /**
+     * The derivation we're trying to substitute
+     */
+    StorePath drvPath;
+
+public:
+    DerivationResolutionGoal(const StorePath & storePath, Worker & worker);
+
+    /**
+     * The resolved derivation, if we succeeded.
+     */
+    std::shared_ptr<BasicDerivation> resolvedDrv;
+
+    /**
+     * The path to derivation above, if we succeeded.
+     *
+     * Garbage that should not be read otherwise.
+     */
+    StorePath resolvedDrvPath = StorePath::dummy;
+
+    Co init();
+
+    void timedOut(Error && ex) override
+    {
+        unreachable();
+    };
+
+    std::string key() override;
+
+    void handleEOF(Descriptor fd) override;
+
+    JobCategory jobCategory() const override
+    {
+        return JobCategory::Substitution;
+    };
+};
+
+}

src/libstore/include/nix/store/build/drv-output-substitution-goal.hh

@@ -35,12 +35,6 @@ public:
         RepairFlag repair = NoRepair,
         std::optional<ContentAddress> ca = std::nullopt);
 
-    /**
-     * The realisation corresponding to the given output id.
-     * Will be filled once we can get it.
-     */
-    std::shared_ptr<const UnkeyedRealisation> outputInfo;
-
     Co init();
 
     void timedOut(Error && ex) override

src/libstore/include/nix/store/build/worker.hh

@@ -19,6 +19,8 @@ struct DerivationGoal;
 struct DerivationBuildingGoal;
 struct PathSubstitutionGoal;
 class DrvOutputSubstitutionGoal;
+class BuildTraceGoal;
+class DerivationResolutionGoal;
 
 /**
  * Workaround for not being able to declare a something like
@@ -35,6 +37,8 @@ class DrvOutputSubstitutionGoal;
 GoalPtr upcast_goal(std::shared_ptr<PathSubstitutionGoal> subGoal);
 GoalPtr upcast_goal(std::shared_ptr<DrvOutputSubstitutionGoal> subGoal);
 GoalPtr upcast_goal(std::shared_ptr<DerivationGoal> subGoal);
+GoalPtr upcast_goal(std::shared_ptr<BuildTraceGoal> subGoal);
+GoalPtr upcast_goal(std::shared_ptr<DerivationResolutionGoal> subGoal);
 
 typedef std::chrono::time_point<std::chrono::steady_clock> steady_time_point;
 
@@ -108,12 +112,14 @@ private:
      * same derivation / path.
      */
 
+    DerivedPathMap<std::weak_ptr<BuildTraceGoal>> buildTraceGoals;
     DerivedPathMap<std::map<OutputsSpec, std::weak_ptr<DerivationCreationAndRealisationGoal>>> derivationCreationAndRealisationGoals;
 
     std::map<StorePath, std::map<OutputName, std::weak_ptr<DerivationGoal>>> derivationGoals;
     std::map<StorePath, std::weak_ptr<DerivationBuildingGoal>> derivationBuildingGoals;
     std::map<StorePath, std::weak_ptr<PathSubstitutionGoal>> substitutionGoals;
     std::map<DrvOutput, std::weak_ptr<DrvOutputSubstitutionGoal>> drvOutputSubstitutionGoals;
+    std::map<StorePath, std::weak_ptr<DerivationResolutionGoal>> derivationResolutionGoals;
 
     /**
      * Goals waiting for busy paths to be unlocked.
@@ -230,11 +236,26 @@ public:
         BuildMode buildMode = bmNormal);
 
     /**
-     * @ref PathSubstitutionGoal "substitution goal"
+     * @ref PathSubstitutionGoal "path substitution goal"
      */
     std::shared_ptr<PathSubstitutionGoal> makePathSubstitutionGoal(const StorePath & storePath, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
+
+    /**
+     * @ref DrvOutputSubstitutionGoal "derivation output substitution goal"
+     */
     std::shared_ptr<DrvOutputSubstitutionGoal> makeDrvOutputSubstitutionGoal(const DrvOutput & id, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
 
+    /**
+     * @ref BuildTraceGoal "derivation output substitution goal"
+     */
+    std::shared_ptr<BuildTraceGoal> makeBuildTraceGoal(
+        const SingleDerivedPath::Built & key);
+
+    /**
+     * @ref DerivationResolutionGoal "derivation resolution goal"
+     */
+    std::shared_ptr<DerivationResolutionGoal> makeDerivationResolutionGoal(const StorePath & drvPath);
+
     /**
      * Make a goal corresponding to the `DerivedPath`.
      *

src/libstore/include/nix/store/meson.build

@@ -12,10 +12,12 @@ config_pub_h = configure_file(
 headers = [config_pub_h] + files(
   'binary-cache-store.hh',
   'build-result.hh',
+  'build/build-trace-goal.hh',
   'build/derivation-goal.hh',
   'build/derivation-building-goal.hh',
   'build/derivation-building-misc.hh',
   'build/derivation-creation-and-realisation-goal.hh',
+  'build/derivation-resolution-goal.hh',
   'build/drv-output-substitution-goal.hh',
   'build/goal.hh',
   'build/substitution-goal.hh',

src/libstore/meson.build

@@ -253,9 +253,12 @@ subdir('nix-meson-build-support/common')
 sources = files(
   'binary-cache-store.cc',
   'build-result.cc',
+  'build/build-trace-goal.cc',
   'build/derivation-goal.cc',
   'build/derivation-building-goal.cc',
   'build/derivation-creation-and-realisation-goal.cc',
+  'build/derivation-goal.cc',
+  'build/derivation-resolution-goal.cc',
   'build/drv-output-substitution-goal.cc',
   'build/entry-points.cc',
   'build/goal.cc',