libstore: move Goal::amDone to Worker

we still mutate goal state to store the results of any given goal run,
but now we also have that information in Worker and could in theory do
something else with it. we could return a map of goal to goal results,
which would also let us better diagnose failures of subgoals (at all).

Change-Id: I1df956bbd9fa8cc9485fb6df32918d68dda3ff48

src/libstore/build/derivation-goal.cc

@@ -1534,7 +1534,10 @@ Goal::Finished DerivationGoal::done(
         fs << worker.store.printStorePath(drvPath) << "\t" << buildResult.toString() << std::endl;
     }
 
-    return amDone(buildResult.success() ? ecSuccess : ecFailed, std::move(ex));
+    return Finished{
+        .result = buildResult.success() ? ecSuccess : ecFailed,
+        .ex = ex ? std::make_unique<Error>(std::move(*ex)) : nullptr,
+    };
 }
 
 

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

@@ -26,7 +26,7 @@ Goal::WorkResult DrvOutputSubstitutionGoal::init()
 
     /* If the derivation already exists, we’re done */
     if (worker.store.queryRealisation(id)) {
-        return amDone(ecSuccess);
+        return Finished{ecSuccess};
     }
 
     subs = settings.useSubstitutes ? getDefaultSubstituters() : std::list<ref<Store>>();
@@ -60,7 +60,7 @@ Goal::WorkResult DrvOutputSubstitutionGoal::tryNext()
         /* Hack: don't indicate failure if there were no substituters.
            In that case the calling derivation should just do a
            build. */
-        return amDone(substituterFailed ? ecFailed : ecNoSubstituters);
+        return Finished{substituterFailed ? ecFailed : ecNoSubstituters};
     }
 
     sub = subs.front();
@@ -137,7 +137,9 @@ Goal::WorkResult DrvOutputSubstitutionGoal::outPathValid()
 
     if (nrFailed > 0) {
         debug("The output path of the derivation output '%s' could not be substituted", id.to_string());
-        return amDone(nrNoSubstituters > 0 || nrIncompleteClosure > 0 ? ecIncompleteClosure : ecFailed);
+        return Finished{
+            nrNoSubstituters > 0 || nrIncompleteClosure > 0 ? ecIncompleteClosure : ecFailed
+        };
     }
 
     worker.store.registerDrvOutput(*outputInfo);
@@ -147,7 +149,7 @@ Goal::WorkResult DrvOutputSubstitutionGoal::outPathValid()
 Goal::WorkResult DrvOutputSubstitutionGoal::finished()
 {
     trace("finished");
-    return amDone(ecSuccess);
+    return Finished{ecSuccess};
 }
 
 std::string DrvOutputSubstitutionGoal::key()

src/libstore/build/goal.cc

@@ -45,31 +45,6 @@ void Goal::waiteeDone(GoalPtr waitee, ExitCode result)
 }
 
 
-Goal::Finished Goal::amDone(ExitCode result, std::optional<Error> ex)
-{
-    trace("done");
-    assert(!exitCode.has_value());
-    exitCode = result;
-
-    if (ex) {
-        if (!waiters.empty())
-            logError(ex->info());
-        else
-            this->ex = std::make_unique<Error>(std::move(*ex));
-    }
-
-    for (auto & i : waiters) {
-        GoalPtr goal = i.lock();
-        if (goal) goal->waiteeDone(shared_from_this(), result);
-    }
-    waiters.clear();
-    worker.removeGoal(shared_from_this());
-
-    cleanup();
-    return Finished{};
-}
-
-
 void Goal::trace(std::string_view s)
 {
     debug("%1%: %2%", name, s);

src/libstore/build/goal.hh

@@ -105,10 +105,13 @@ struct Goal : public std::enable_shared_from_this<Goal>
 
 public:
 
-    struct StillAlive {};
-    struct Finished {};
+    struct [[nodiscard]] StillAlive {};
+    struct [[nodiscard]] Finished {
+        ExitCode result;
+        std::unique_ptr<Error> ex;
+    };
 
-    struct WorkResult : std::variant<StillAlive, Finished>
+    struct [[nodiscard]] WorkResult : std::variant<StillAlive, Finished>
     {
         WorkResult() = delete;
         using variant::variant;
@@ -159,8 +162,6 @@ public:
 
     virtual std::string key() = 0;
 
-    Finished amDone(ExitCode result, std::optional<Error> ex = {});
-
     virtual void cleanup() { }
 
     /**

src/libstore/build/substitution-goal.cc

@@ -35,7 +35,7 @@ Goal::Finished PathSubstitutionGoal::done(
         debug(*errorMsg);
         buildResult.errorMsg = *errorMsg;
     }
-    return amDone(result);
+    return Finished{result};
 }
 
 

src/libstore/build/worker.cc

@@ -139,6 +139,40 @@ static void removeGoal(std::shared_ptr<G> goal, std::map<K, std::weak_ptr<G>> &
 }
 
 
+void Worker::goalFinished(GoalPtr goal, Goal::Finished & f)
+{
+    goal->trace("done");
+    assert(!goal->exitCode.has_value());
+    goal->exitCode = f.result;
+
+    if (f.ex) {
+        if (!goal->waiters.empty())
+            logError(f.ex->info());
+        else
+            goal->ex = std::move(f.ex);
+    }
+
+    for (auto & i : goal->waiters) {
+        if (GoalPtr waiting = i.lock()) {
+            waiting->waiteeDone(goal, f.result);
+        }
+    }
+    goal->waiters.clear();
+    removeGoal(goal);
+    goal->cleanup();
+}
+
+void Worker::handleWorkResult(GoalPtr goal, Goal::WorkResult how)
+{
+    std::visit(
+        overloaded{
+            [&](Goal::StillAlive) {},
+            [&](Goal::Finished & f) { goalFinished(goal, f); },
+        },
+        how
+    );
+}
+
 void Worker::removeGoal(GoalPtr goal)
 {
     if (auto drvGoal = std::dynamic_pointer_cast<DerivationGoal>(goal))
@@ -299,7 +333,7 @@ void Worker::run(const Goals & _topGoals)
             awake.clear();
             for (auto & goal : awake2) {
                 checkInterrupt();
-                goal->work();
+                handleWorkResult(goal, goal->work());
 
                 actDerivations.progress(
                     doneBuilds, expectedBuilds + doneBuilds, runningBuilds, failedBuilds
@@ -429,9 +463,14 @@ void Worker::waitForInput()
             j->respectTimeouts &&
             after - j->lastOutput >= std::chrono::seconds(settings.maxSilentTime))
         {
+            handleWorkResult(
+                goal,
                 goal->timedOut(Error(
                     "%1% timed out after %2% seconds of silence",
-                    goal->getName(), settings.maxSilentTime));
+                    goal->getName(),
+                    settings.maxSilentTime
+                ))
+            );
             continue;
         }
 
@@ -440,9 +479,12 @@ void Worker::waitForInput()
             j->respectTimeouts &&
             after - j->timeStarted >= std::chrono::seconds(settings.buildTimeout))
         {
-            goal->timedOut(Error(
-                    "%1% timed out after %2% seconds",
-                    goal->getName(), settings.buildTimeout));
+            handleWorkResult(
+                goal,
+                goal->timedOut(
+                    Error("%1% timed out after %2% seconds", goal->getName(), settings.buildTimeout)
+                )
+            );
             continue;
         }
 
@@ -469,7 +511,7 @@ void Worker::waitForInput()
                         goal->getName(), rd);
                     std::string_view data((char *) buffer.data(), rd);
                     j->lastOutput = after;
-                    goal->handleChildOutput(k, data);
+                    handleWorkResult(goal, goal->handleChildOutput(k, data));
                 }
             }
         }

src/libstore/build/worker.hh

@@ -105,6 +105,9 @@ private:
      */
     std::map<StorePath, bool> pathContentsGoodCache;
 
+    void goalFinished(GoalPtr goal, Goal::Finished & f);
+    void handleWorkResult(GoalPtr goal, Goal::WorkResult how);
+
 public:
 
     const Activity act;