On Thu, Jul 2, 2020 at 8:45 AM Mathias Gaunard via Boost <boost@lists.boost.org> wrote:

I don't think those changes should be rushed. If Boost.Asio is causing breakage across other Boost libraries, then the best thing to do is to delay the Boost.Asio changes.

For political reasons related to wg21 it is very important that Beast support these changes in THIS release. It will be of great value in helping to ensure that the design of Networking TS is tinkered with only a little bit in LEWG's hands rather than a lot (although anything can happen). The literal future of C++ networking is at stake. Thanks

Copied here as I incorrectly replied direct. On Thu, 2 Jul 2020 at 17:39, Mathias Gaunard <mathias.gaunard@ens-lyon.org> wrote:

On Thu, 2 Jul 2020 at 16:21, Richard Hodges via Boost <boost@lists.boost.org> wrote:

...

At the present time, Chris is working to finalise some significant changes to Asio. These changes have required some refactoring of Boost.Beast at short notice in order to continue to provide a functioning library.

I don't think those changes should be rushed. If Boost.Asio is causing breakage across other Boost libraries, then the best thing to do is to delay the Boost.Asio changes.

Users of existing (1.73) Asio can avoid breakage with asio-only programs by not defining the macro BOOST_ASIO_NO_DEPRECATED

Also if Boost.Beast is broken, there are chances other users outside of Boost will be broken as well, so maybe something to consider?

In Beast we make a point of ensuring that Beast will function when BOOST_ASIO_NO_DEPRECATED is defined so as not to unnecessarily restrict user's code. Furthermore this time around we are faced with a new macro BOOST_BEAST_NO_TS_EXECUTORS, which completely removes the executors that were introduced as recently as Boost 1.70. Again, we feel obligated to ensure that user code compiles and functions correctly if this macro is defined. This is only my second Boost release, but I am given to understand that last-minute rewrites of Asio are not unusual. Chris has been as helpful as the 12-hour time-zone difference has allowed. We have been feeding back test results and receiving updates for the past week. I have no doubt that he will prevail, at least insofar as fixing the one last minor bug that is blocking us in the c++20 build. Once again, thanks for everyone's patience. "I picked the wrong week to stop sniffing glue" *- Airplane!* On Thu, 2 Jul 2020 at 17:39, Mathias Gaunard <mathias.gaunard@ens-lyon.org> wrote:

On Thu, 2 Jul 2020 at 16:21, Richard Hodges via Boost <boost@lists.boost.org> wrote:

...

At the present time, Chris is working to finalise some significant changes to Asio. These changes have required some refactoring of Boost.Beast at short notice in order to continue to provide a functioning library.

I don't think those changes should be rushed. If Boost.Asio is causing breakage across other Boost libraries, then the best thing to do is to delay the Boost.Asio changes.

Also if Boost.Beast is broken, there are chances other users outside of Boost will be broken as well, so maybe something to consider?

-- Richard Hodges hodges.r@gmail.com office: +442032898513 home: +376841522 mobile: +376380212

On Thu, Jul 2, 2020 at 11:28 AM Robert Ramey via Boost <boost@lists.boost.org> wrote:

I agree with this.

That's very nice but worth precisely nothing, because you have no skin in the game at all. A delay means that for the next four months of SG4 Networking meetings we will have no field experience or knowledge to use to negate bad ideas that are brought before the committee. It is worth the risk. Thanks

On Thu, Jul 2, 2020 at 11:50 AM Ville Voutilainen <ville.voutilainen@gmail.com> wrote:

110%

(Note that 112% is the correct number)

"WG21 politics" as you call them do not constitute a reason to release a possibly low-quality boost.

That is certainly true, but since Asio's changes are beyond my control it is important for Beast to be up-to-date with respect to those changes in the same release, not one release later.

You can appeal to existing implementation experience until the cows come home, but that alone doesn't guarantee that LEWG and WG21 end up standardizing an existing API without modifying it.

There is a certain principle of loyalty and professional respect at play here. Christopher Kohlhoff is working hard on his own personal time with no corporate sponsor to bring us sane, robust networking while also working full time to keep the lights on. As my co-workers and I are team players we support Chris 112% by making sure that Beast supports the changes in Asio as soon as possible. Beast has always supported the latest changes in Asio and will continue to do so. Thanks

On 2020-07-03 12:25, Paul A Bristow via Boost wrote:

...

-----Original Message----- From: Boost <boost-bounces@lists.boost.org> On Behalf Of Vinnie Falco via Boost Sent: 2 July 2020 20:25 To: Ville Voutilainen <ville.voutilainen@gmail.com> Cc: Vinnie Falco <vinnie.falco@gmail.com>; boost@lists.boost.org List <boost@lists.boost.org>; Robert Ramey <ramey@rrsd.com> Subject: Re: [boost] Boost.Beast state of play

On Thu, Jul 2, 2020 at 11:50 AM Ville Voutilainen <ville.voutilainen@gmail.com> wrote:

...

110%

(Note that 112% is the correct number)

...

"WG21 politics" as you call them do not constitute a reason to release a possibly low-quality boost.

That is certainly true, but since Asio's changes are beyond my control it is important for Beast to be up- to-date with respect to those changes in the same release, not one release later.

All Boost releases risk causing someone trouble (and one way or another most do).

IMO Vinnie has made a good enough case for *this issue* on *this release*.

Vinnie's case was "because of WG21 politics". This is not a valid reason to compromise Boost quality, I totally agree with Ville on this. I find it somewhat disturbing that maintainers of a popular Boost library find that acceptable. Boost users experience should have a priority over WG21. Richard, however, presented a different case, that is: - Only a single test case is broken in a single configuration. - The test uses modern C++ features, which are expected to be rather unstable at this point. - There is a high chance that Chris will fix the problem before the release. Also, if I'm not mistaken, in the previous Boost release Boost.Beast had a problem in the same area, so basically Boost.Beast is not worse than the previous release. This is a more compelling case. I'd like to ask Richard to let us know if and when this problem gets resolved.

On Fri, 3 Jul 2020 at 20:25, Andrey Semashev via Boost <boost@lists.boost.org> wrote:

On 2020-07-03 12:25, Paul A Bristow via Boost wrote:

...

All Boost releases risk causing someone trouble (and one way or another most do).

IMO Vinnie has made a good enough case for *this issue* on *this release*.

Vinnie's case was "because of WG21 politics". This is not a valid reason to compromise Boost quality, I totally agree with Ville on this. I find it somewhat disturbing that maintainers of a popular Boost library find that acceptable. Boost users experience should have a priority over WG21.

Richard, however, presented a different case, that is:

- Only a single test case is broken in a single configuration. - The test uses modern C++ features, which are expected to be rather unstable at this point. - There is a high chance that Chris will fix the problem before the release.

And Chris presented the features available as a consequence of these changes, and the options for users. My comments below are as a user of asio and Beast (and a lot of other Boost libraries - not all ones that have become or are likely to become part of std::). On Fri, 3 Jul 2020 at 11:11, Christopher Kohlhoff via Boost <boost@lists.boost.org> wrote:

1) BOOST_ASIO_NO_DEPRECATED

The handler invocation and allocation hooks were superseded and deprecated back in Boost 1.66, with the introduction of the networking TS compatibility:

<https://www.boost.org/doc/libs/1_66_0/doc/html/boost_asio/net_ts.html>

The only deprecation-related change for Asio in Boost 1.74 is that these hooks are now covered by BOOST_ASIO_NO_DEPRECATED. This will help users find and replace their usage of the hooks in their applications.

Beast changed to respect the definition of BOOST_ASIO_NO_DEPRECATED in relation to these hooks.

Nice. I like this so I can do that (find usage of deprecated hooks).

2) BOOST_ASIO_NO_TS_EXECUTORS

With Boost 1.74, Asio adds an implementation of the proposed C++23 standard executors. This is in addition to the existing executors implementation which is defined in the networking TS.

Most applications will require no modification, or very little. If absolutely necessary, users can define BOOST_ASIO_USE_TS_EXECUTOR_AS_DEFAULT to enable full backward compatibility.

Nice to know I can do this if I need to.

A user may choose to define BOOST_ASIO_NO_TS_EXECUTORS so that they can disable networking TS executors entirely, and use only the proposed C++23 executors. Even when this is defined, unless interacting directly with executors at a low level, most code will require little or no change.

I don't want to do that - yet. But it's a nice-to-have for when/if there is a C++23 executor impl I want to use (for me, no rush, and certainly not in prod code).

Beast changed as follows:

* To support the proposed C++23 standard executors implementation as an additive feature.

* To respect the user's definition of BOOST_ASIO_NO_TS_EXECUTORS.

Good to know that whatever pain this migration may entail, Beast has it covered and I can experiment not just with my code that uses asio but also in code that uses Beast.

The common theme here is that these changes impact Beast more than they will impact end users, because Beast opts to support and pass through Asio's latest features without attenuation. This allows Beast users to employ these latest features in their applications.

I'm really happy to see this approach. It seems to be exactly what Boost should be doing. As a Boost user, I won't update to the new Boost release in existing production code without careful consideration of any impacts. On the other hand, I will, in new or evolving code, be keen to use new features and stop using deprecated ones - the fact that I can do both using this release is ideal. This is a great example of effectively resolving the conflict between Boost as a distribution of high quality code one can depend on (in some cases for many years) when that code is not part of the standard (or the standard library being used) and also providing a whole environment that can evolve and test the fitness of both the existing (through adaptation) and then newcomer (through filling a niche in this ecosystem). This effort should be applauded - including the level of testing of new unusual configurations being performed. If only every library/product was as thorough. I don't see this as an indication of dropping the quality of the release at all.

On 03/07/2020 11:24, Andrey Semashev via Boost wrote:

Vinnie's case was "because of WG21 politics". This is not a valid reason to compromise Boost quality, I totally agree with Ville on this. I find it somewhat disturbing that maintainers of a popular Boost library find that acceptable. Boost users experience should have a priority over WG21.

It's funny how Boost.ASIO has suddenly gone from being a very, very conservative flavour of standalone ASIO, typically trailing by a few major versions, to where "the stable branch" is code literally written new in the last few weeks, and with a major rearchitecture to boot. In the end, each library maintainer gets to make that call for their own library. But I've always gotten the impression from others here that major new features should either get a mini review (unnecessary in this instance due to the WG21 review), or undergo at least a year of testing, and then ought to be preannounced by least two major Boost releases in advance before they get merged to master branch. As an example, I've just announced that Outcome will break all existing code in two Boost releases time in the Boost changelog. I have been announcing it on the front page since last Christmas. Now, little in latest Boost.ASIO will break existing code in obvious ways. But I have to believe that newly written code is usually more buggy and/or surprising than older code. It seems unusual to me to launch that onto users without notification. Again, if that maintainer doesn't mind the onslaught of bug reports, especially from downstream distros e.g. RHEL, Debian, StackOverflow, that's on them. I just find it masochistic, that's all. Niall

On 03/07/2020 16:56, Vinnie Falco wrote:

On Fri, Jul 3, 2020 at 6:55 AM Niall Douglas via Boost <boost@lists.boost.org> wrote:

...

...Outcome will break all existing code...

Chris K: "Asio is getting some API changes this release" Beast: "Beast is tracking Asio's API changes this release" Niall: "Hold my beer..."

The upgrade path from Outcome v2.1 to v2.2 is well documented. Lots of production codebases have been on v2.2 for many months now, including my work's. Converting over the codebase took less than 15 minutes if you follow the guide. A full calender year of notice has been given that this is coming. And moreover, it was always made clear from the beginning that we would do at least one big breaking API change before we go permanently ABI stable, for which it is extremely important we never ever change much of anything ever again thereafter. Niall

On 7/3/20 9:45 AM, Peter Dimov via Boost wrote: ...

2. Update master

This is supposed to get feedback from outside users who track master in order to not be surprised by the release, but in practice, no such people seem to exist, so it mostly gets feedback from Boost library developers who erroneously test against master.

LOL erroneously? - one is allowed to name names. As one who tests against master for reasons I've specified elsewhere, I should say: a) I almost never find bugs/unannounced changes in the master API. b) But truth is, I generally pull from the master branch only when I'm about to check my own code into the master. So I'm not providing much feedback as things mostly work by the time they get checked into the master.

I'd still call the above schedule "best practice" though; or if not that, its compressed form where (1) is at beginning of N, (2) is in the middle.

+1 The current setup works well and decouples one's development from the release schedule. We should continue to rely on that. Robert Ramey

On Fri, Jul 3, 2020 at 6:55 AM Niall Douglas via Boost <boost@lists.boost.org> wrote:

code literally written new in the last few weeks, and with a major rearchitecture to boot.

There's no "major rearchitecture" in this new version of Asio, it is just a refactoring and changing of spelling of the interfaces to executors. They still do the same things: * maybe track outstanding work * hint to the context that the submitted function object represents a continuation of a larger I/O operation * get the execution context from an executor * provide a polymorphic executor type Except that the incantations required of users is now different (net::require and net::prefer for example, are new ways to do old things). It is still the same Asio under the hood. None of the fundamental design is different, and most users won't notice these changes. Thanks