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

[Jonathan Wakely]

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.