From 398894b85672f5197b5fc3eeae3fa2ec32f03908 Mon Sep 17 00:00:00 2001
From: eldritch horrors <pennae@lix.systems>
Date: Sun, 25 Aug 2024 13:41:56 +0200
Subject: [PATCH] libstore: make Goal::ex a shared_ptr

this makes WorkResult copyable, and just all around easier to deal with.
in the future we'll need this to let Goal::work() return a promise for a
WorkResult (or even just a Finished) that can be awaited by other goals.

Change-Id: Ic5a1ce04c5a0f8e683bd00a2ed2b77a2e28989c1
---
 src/libstore/build/derivation-goal.cc | 2 +-
 src/libstore/build/entry-points.cc    | 4 ++--
 src/libstore/build/goal.hh            | 4 ++--
 src/libstore/build/worker.cc          | 2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index 2638d7395..f2c8ccc5f 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -1545,7 +1545,7 @@ Goal::Finished DerivationGoal::done(
 
     return Finished{
         .result = buildResult.success() ? ecSuccess : ecFailed,
-        .ex = ex ? std::make_unique<Error>(std::move(*ex)) : nullptr,
+        .ex = ex ? std::make_shared<Error>(std::move(*ex)) : nullptr,
         .permanentFailure = buildResult.status == BuildResult::PermanentFailure,
         .timedOut = buildResult.status == BuildResult::TimedOut,
         .hashMismatch = anyHashMismatchSeen,
diff --git a/src/libstore/build/entry-points.cc b/src/libstore/build/entry-points.cc
index c6955600e..f52f2876f 100644
--- a/src/libstore/build/entry-points.cc
+++ b/src/libstore/build/entry-points.cc
@@ -16,13 +16,13 @@ void Store::buildPaths(const std::vector<DerivedPath> & reqs, BuildMode buildMod
     worker.run(goals);
 
     StringSet failed;
-    std::optional<Error> ex;
+    std::shared_ptr<Error> ex;
     for (auto & i : goals) {
         if (i->ex) {
             if (ex)
                 logError(i->ex->info());
             else
-                ex = std::move(*i->ex);
+                ex = i->ex;
         }
         if (i->exitCode != Goal::ecSuccess) {
             if (auto i2 = dynamic_cast<DerivationGoal *>(i.get()))
diff --git a/src/libstore/build/goal.hh b/src/libstore/build/goal.hh
index 4ff4a14f8..1bfea8231 100644
--- a/src/libstore/build/goal.hh
+++ b/src/libstore/build/goal.hh
@@ -118,7 +118,7 @@ public:
     };
     struct [[nodiscard]] Finished {
         ExitCode result;
-        std::unique_ptr<Error> ex;
+        std::shared_ptr<Error> ex;
         bool permanentFailure = false;
         bool timedOut = false;
         bool hashMismatch = false;
@@ -141,7 +141,7 @@ public:
     /**
      * Exception containing an error message, if any.
      */
-    std::unique_ptr<Error> ex;
+    std::shared_ptr<Error> ex;
 
     explicit Goal(Worker & worker)
         : worker(worker)
diff --git a/src/libstore/build/worker.cc b/src/libstore/build/worker.cc
index 4a70b272a..1b4633e64 100644
--- a/src/libstore/build/worker.cc
+++ b/src/libstore/build/worker.cc
@@ -150,7 +150,7 @@ void Worker::goalFinished(GoalPtr goal, Goal::Finished & f)
         if (!goal->waiters.empty())
             logError(f.ex->info());
         else
-            goal->ex = std::move(f.ex);
+            goal->ex = f.ex;
     }
 
     for (auto & i : goal->waiters) {