libstore: remove Goal::WaitForWorld

have DerivationGoal and its subclasses produce a wrapper promise for
their intermediate results instead, and return this wrapper promise.
Worker already handles promises that do not complete immediately, so
we do not have to duplicate this into an entire result type variant.

Change-Id: Iae8dbf63cfc742afda4d415922a29ac5a3f39348

1 files changed, 14 insertions, 1 deletions

diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index b8c4d278d..037b4fb10 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -787,7 +787,7 @@ try {
                     buildResult.startTime = time(0); // inexact
                     state = &DerivationGoal::buildDone;
                     started();
-                    return {{WaitForWorld{std::move(a.promise)}}};
+                    return continueOrError(std::move(a.promise));
                 },
                 [&](HookReply::Postpone) -> std::optional<kj::Promise<Result<WorkResult>>> {
                     /* Not now; wait until at least one child finishes or
@@ -1756,4 +1756,17 @@ void DerivationGoal::waiteeDone(GoalPtr waitee)
     }
 }
 
+kj::Promise<Result<Goal::WorkResult>>
+DerivationGoal::continueOrError(kj::Promise<Outcome<void, Goal::Finished>> p)
+{
+    return p.then([](auto r) -> Result<WorkResult> {
+        if (r.has_value()) {
+            return ContinueImmediately{};
+        } else if (r.has_error()) {
+            return r.assume_error();
+        } else {
+            return r.assume_exception();
+        }
+    });
+}
 }