[PATCH] PR libstdc++/80316 make promise::set_value throw no_state error

[Jonathan Wakely]

On 11/07/17 12:53 +0100, Jonathan Wakely wrote:
>On 21/04/17 15:54 +0100, Jonathan Wakely wrote:
>>On 4 April 2017 at 20:44, Jonathan Wakely wrote:
>>>We got a bug report from a customer pointing out that calling
>>>promise::set_value on a moved-from promise crashes instead of throwing
>>>an exception with error code future_errc::no_state.
>>>
>>>This fixes it, by moving the _S_check calls to *before* we deference
>>>the pointer that the calls check!
>>>
>>>This passes all tests, including the more comprehensive ones I've
>>>added as part of this commit, but I think it can wait for stage 1
>>>anyway. We've been shipping this bug for a couple of releases already.
>>>
>>>        PR libstdc++/80316
>>>        * include/std/future (_State_baseV2::_Setter::operator()): Remove
>>>        _S_check calls that are done after the pointer to the shared state
>>>is
>>>        already dereferenced.
>>>        (_State_baseV2::_Setter<_Res, void>): Define specialization for void
>>>        as partial specialization so it can be defined within the definition
>>>        of _State_baseV2.
>>>        (_State_baseV2::__setter): Call _S_check.
>>>        (_State_baseV2::__setter(promise<void>*)): Add overload for use by
>>>        promise<void>::set_value and
>>>promise<void>::set_value_at_thread_exit.
>>>        (promise<T>, promise<T&>, promise<void>): Make _State a friend.
>>>        (_State_baseV2::_Setter<void, void>): Remove explicit
>>>specialization.
>>>        (promise<void>::set_value, promise<void>::set_value_at_thread_exit):
>>>        Use new __setter overload.
>>>        * testsuite/30_threads/promise/members/at_thread_exit2.cc: New test.
>>>        * testsuite/30_threads/promise/members/set_exception.cc: Test
>>>        promise<T&> and promise<void> specializations.
>>>        * testsuite/30_threads/promise/members/set_exception2.cc: Likewise.
>>>        Test for no_state error condition.
>>>        * testsuite/30_threads/promise/members/set_value2.cc: Likewise.
>>
>>
>>This is now committed to trunk.
>
>And now also to gcc-7-branch.

And gcc-6-branch.