Re: Request for 1.73 patch release

From: Richard Hodges (hodges.r_at_[hidden])
Date: 2020-05-02 21:49:49

On Sat, 2 May 2020 at 23:09, Richard Hodges <hodges.r_at_[hidden]> wrote:

> Thank you all for your help and attention.
>
> I have been spending the day investigating the root cause of compilation
> problems and extensively testing our fix.
>
> In summary, I am inclined to de-escalate for now as I have discovered that
> neither
>
> * clang-10 -std=c++20, nor
> * gcc-10 -std=c++20
>
> will compile any asio program which involves a call to asio::co_spawn,
> which is fundamental requirement in a coroutine-enabled asio program.
>
> What seems to be happening is that when concepts are enabled (which they
> are in the above compilers) asio is checking the result_of the supplied
> coroutine.
>
> In clang-9 with -fcoroutines-ts, concepts are not enabled, so the check is
> not made.
>
> I thinik I have been told previously by Lewis that it's not possible to
> take the result_of a coroutine. It's entirely possible that I have
> misunderstood as coroutine implementation is not yet my domain of expertise.
>
> In summary, one of either (Asio && MSVC) || (clang && gcc) are in the
> wrong.
>
> I am not qualified to say which at this stage.
>
> I suspect there's a workaround in clang & gcc which will involve using
> macro definitions to convince asio that concepts are not available when
> compiled in c++20.
>

Confirmed: adding -DBOOST_ASIO_DISABLE_CONCEPTS  to the command line
options of clang-10 allows compilation.

>
> It's late for me now but I'll check this train of thought in the morning.
>
> R
>
>
> On Sat, 2 May 2020 at 22:11, Robert Ramey via Boost <boost_at_[hidden]>
> wrote:
>
>> On 5/2/20 10:44 AM, Vinnie Falco via Boost wrote:
>> > On Sat, May 2, 2020 at 9:34 AM Glen Fernandes <glen.fernandes_at_[hidden]>
>> wrote:
>> >> A new release is costly
>> >
>> > Understood. The problem is that the Boost 1.73 release as it is
>> > currently shipped, has a Beast that does not work with C++20
>> > coroutines. Thus one or more other individuals besides me and Richard
>> > should decide if this is important enough to justify the cost of a new
>> > release. I can go either way on it. The fixes are stable and well
>> > tested.
>> >
>>
>> We'll have another release in 2-4 months.  I very much doubt that there
>> are many users who are currently using Beast with C++20.  And I don't
>> see a huge hardship if those users need to wait a couple of months.  I
>> just don't see that a patch is worth all the extra work, including
>> distribution, publicity, and confusion it might cause. Onward !!! don't
>> waste time looking back.
>>
>> better to spend a little more time to tweak the testing/release process
>> so that such a thing can't recurre.
>>
>> Robert Ramey
>>
>> > Thanks
>> >
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>>
>>
>>
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>
>
> --
> Richard Hodges
> hodges.r_at_[hidden]
> office: [phone]
> home: [phone]
> mobile: [phone]
>
>

-- 
Richard Hodges
hodges.r_at_[hidden]
office: [phone]
home: [phone]
mobile: [phone]