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https://issues.apache.org/jira/browse/MESOS-6484?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15614689#comment-15614689
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Alexander Rojas commented on MESOS-6484:
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So, here is how the leak works: An object {{Future<T>}} is a wrapper for
{{std::shared_ptr<Future<T>::Data> data}}. This part of the code
{{lambda::bind(&internal::expired<T>, f, latch, promise, *this)}} creates a
copy of {{this}}, where {{data}} is pointed to by {{this}} and the new copy of
the future. This copy is stored in the callable object created by
{{lambda::bind()}} to be executed in the future. When we execute the
{{onAny(lambda::bind(&internal::after<T>, latch, promise, timer,
lambda::_1))}}, a callable object with a copy of {{timer}} is stored in the
{{onAnyCallbacks}} which is in itself stored in {{data}}, which ends up being
{{data}} having indirectly a reference counted pointer to itself, therefore it
will never be destroyed.
> Memory leak in `Future<T>::after()`
> -----------------------------------
>
> Key: MESOS-6484
> URL: https://issues.apache.org/jira/browse/MESOS-6484
> Project: Mesos
> Issue Type: Bug
> Components: libprocess
> Affects Versions: 1.1.0
> Reporter: Alexander Rojas
> Labels: libprocess, mesosphere
>
> The problem arises when one tries to associate an {{after()}} call to copied
> futures. The following test case is enough to reproduce the issue:
> {code}
> TEST(FutureTest, After3)
> {
> auto policy = std::make_shared<int>(0);
> {
> auto generator = []() {
> return Future<Nothing>();
> };
> Future<Nothing> future = generator()
> .after(Milliseconds(1),
> [policy](const Future<Nothing>&) {
> return Nothing();
> });
> AWAIT_READY(future);
> }
> EXPECT_EQ(1, policy.use_count());
> }
> {code}
> In the test, one would expect that there is only one active reference to
> {{policy}}, therefore the expectation {{EXPECT_EQ(1, policy.use_count())}}.
> However, if after is triggered more than once, each extra call adds one
> undeleted reference to {{policy}}.
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