libstore: make non-cache goal pointers strong

without circular references we do not need weak goal pointers except for
caches, which should not prevent goal destructors running. caches though
cannot create circular references even when they keep strong references.
if we removed goals from caches when their work() is fully finished, not
when their destructors are run, we could keep strong pointers in caches.
since we do not gain much from this we keep those pointers weak for now.

Change-Id: I1d4a6850ff5e264443c90eb4531da89f5e97a3a0

1 files changed, 2 insertions, 6 deletions

diff --git a/src/libstore/build/worker.cc b/src/libstore/build/worker.cc
index 1b1bf1d5c..2894620a1 100644
--- a/src/libstore/build/worker.cc
+++ b/src/libstore/build/worker.cc
@@ -44,6 +44,7 @@ Worker::~Worker()
        are in trouble, since goals may call childTerminated() etc. in
        their destructors). */
     topGoals.clear();
+    awake.clear();
     children.clear();
 
     assert(expectedSubstitutions == 0);
@@ -310,12 +311,7 @@ std::vector<GoalPtr> Worker::run(std::function<Targets (GoalFactory &)> req)
         /* Call every wake goal (in the ordering established by
            CompareGoalPtrs). */
         while (!awake.empty() && !topGoals.empty()) {
-            Goals awake2;
-            for (auto & i : awake) {
-                GoalPtr goal = i.lock();
-                if (goal) awake2.insert(goal);
-            }
-            awake.clear();
+            Goals awake2 = std::move(awake);
             for (auto & goal : awake2) {
                 checkInterrupt();
                 auto result = goal->work();