06/11/2019 09:49, Ray Kinsella: > On 06/11/2019 00:11, Thomas Monjalon wrote: > > 05/11/2019 16:24, Ray Kinsella: > >> +#. Major ABI versions are declared every **year** and are then supported > >> for one > >> + year, typically aligned with the :ref:`LTS release > >> <stable_lts_releases>`. > > > > As discussed earlier, a major ABI version can be declared less often > > than one year in the future. > > An ABI is supported more than one year, because of the LTS branches. > > That's why I propose to replace with this sentence: > > " > > Major ABI versions are declared regularly and are then supported for > > at least one year, typically aligned with the :ref:`LTS release > > <stable_lts_releases>`. > > " > > So look, this one was a decision of the technical board.
The techboard didn't decide to change the ABI every year. We decided to review the duration after the first year, with a plan to extend. > My position is still what was agreed was, "declared every year, and supported > for one year". > I like it, it's crystal clear what is the policy, until we change the policy. I think it gives a wrong message. > That said, I can make the change no problem, but I need some others to chime > in to ok it. > Perhaps at the head of the Techboard today? Yes I add it to the techboard meeting. > >> +#. The ABI version is managed at a project level in DPDK, with the ABI > >> version > >> + reflected in all library's soname. > > > > Yes, even the experimental libraries should have the same version, > > with the minor number incremented at each release. > > (just a comment to change a policy at the end of this patch) > > It's described elsewhere in the document, experimental libraries have a major > ABI version of 0, to indicate they exist outside of ABI management. > Minor number then changes as the experimental library changes as before. Yes, but you cannot say "reflected in all library's soname". > >> + In 2019, the DPDK community stated its intention to move to ABI stable > >> + releases, over a number of release cycles. This change begins with > >> + maintaining ABI stability through one year of DPDK releases starting > >> from > >> + DPDK 19.11. This policy will be reviewed in 2020, with intention of > >> + lengthening the stability period. > > > > Great, the schedule is clear here. > > > >> +A major ABI version is declared every year, aligned with that year's LTS > >> +release, e.g. v19.11. This ABI version is then supported for one year by > >> all > >> +subsequent releases within that time period, until the next LTS release, > >> e.g. > >> +v20.11. > > > > Let's reword like this: > > " > > A new major ABI version can be declared when a new LTS branch is started, > > e.g. ABI 19 for DPDK 19.11.0. > > This major ABI version is then supported until the next one, > > e.g. ABI 20 for DPDK 20.11.0. > > All ABI changes must be detailed in the release notes. > > " > > This is more ambiguous, although what I said above stands. What you said is wrong because of 2 reasons: - it is not always one year for an major ABI - it is always longer because of LTS branch > If there is general agreement with changing this part of the policy, I am ok > to make > the change. Yes let's review with the techboard. > >> + ABI breakages due to changes such as reorganizing public > >> + structure fields for aesthetic or readability purposes should be > >> avoided. > > > > Why it should be avoided? > > If the ABI is broken anyway, I don't see any reason to not break it more. > > This is text from the original ABI Policy - I think the general sentiment > still stands. > Just because you have an ABI Breakage window doesn't mean you should feel > free to break > the ABI. The 3 ACKs required from Technical Board member to change the ABI, > are another > reflection of this. > > As a general rule. > Unnecessary changes should still be avoided, to reduce ABI churn between ABI > versions. I agree we must avoid unnecessary API changes because it requires apps to adapt. But if the change is only ABI, and we are in an ABI-change window, I don't see any issue. > >> +#. ABI breaking changes (including an alternative map file) can be > >> included with > >> + deprecation notice, in wrapped way by the ``RTE_NEXT_ABI`` option, to > >> provide > >> + more details about oncoming changes. ``RTE_NEXT_ABI`` wrapper will be > >> removed > >> + at the declaration of the next major ABI version. > > > > I missed that in discussions. > > I thought we wanted to wait for the next major ABI. > > If we allow NEXT_ABI ifdef, we will have 2 DPDK versions > > (stable and next ABI) to test. > > This is text from the original ABI Policy - the purpose remains the same. > If you add an ABI breaking change in say 20.02, that clearly can't see the > light of day until 20.11 > > You may still opt to prepare the community for the change, by putting your > code out wrapped > in a NEXT_ABI and flagging it. You then get the option for people, so > inclined, to build and try your code. > > I can't see it being used often, but it is another tool in the box of > managing ABI change. OK, let's keep this tool. > >> +Libraries marked as ``experimental`` are entirely not considered part of > >> an ABI > >> +version, and may change without warning at any time. Experimental > >> libraries > >> +always have a major version of ``0`` to indicate they exist outside of > >> +ABI Versioning, with the minor version incremented with each ABI change > >> +to library. > > > > It means not all libraries will have the same ABI version. > > It is contrary of "ABI version is managed at a project level", > > and I don't see a real benefit of a different version number. > > There is a benefit, major version 0 is a very clear indication that > the library exists outside of ABI management. > A library isn't in the ABI, until it is in the ABI - an then it gets > added to the major version number. > > > Anyway, some experimental functions can live inside a library > > with a stable ABI version number > > True, but if an entire library is experimental - let's be crystal > clear about that. I would like to see what others think.
