Re: [PATCH v1 0/6] tools/ocaml/xenstored: simplify code

[Wei Liu <wl@xxxxxxx>]

On Tue, Aug 18, 2020 at 01:40:18PM +0100, Andrew Cooper wrote:
> On 18/08/2020 10:25, Christian Lindig wrote:
> > I see little reason to support old OCaml releases and requiring OCaml 4.06 
> > would be fine with me but I assume that the project might have its own 
> > ideas about this.
> >
> > ________________________________________
> > From: Edwin Torok
> > Sent: 18 August 2020 08:28
> > To: Christian Lindig; xen-devel@xxxxxxxxxxxxxxxxxxxx
> > Cc: Ian Jackson; dave@xxxxxxxxxx; wl@xxxxxxx
> > Subject: Re: [PATCH v1 0/6] tools/ocaml/xenstored: simplify code
> >
> > On Mon, 2020-08-17 at 14:56 +0200, Christian Lindig wrote:
> >> This all looks good - I left a small comment on one of the patches
> >> and I agree that this needs testing. I also wonder about
> >> compatibility with earlier OCaml releases that we support but I see
> >> no real obstacles.
> >>
> > I've developed the series using OCaml 4.08.1. I think the newest
> > feature I used was Map.update (OCaml 4.06, nearly 3 years ago).
> > Looking through https://repology.org/project/ocaml/versions I'm not
> > sure if we can require more than 4.05 though.
> > The README in Xen doesn't specify a minimum version, but configure
> > checks for >=4.02.
> >
> > I can try to backport my series to OCaml 4.05 (to use Map.find_opt
> > instead of Map.update) and update the configure check to require 4.05.
> > It would be possible to backport even further to 4.02 by introducing
> > additional inefficiencies (Map.mem + Map.find would traverse the map
> > twice, and Map.find on its own would raise an exception on Not found,
> > which is more costly than returning None in Map.find_opt), I'd avoid
> > doing that.
> >
> > Xen's CI from automation might need some updates to use latest stable
> > versions:
> > * Fedora 29 is EOL, should use at least Fedora 31
> > * Debian Jessie is EOL. Stretch is present, but Buster is missing
> 
> We're working on the CI loop.
> 
> As maintainer, it is ultimately Christian's choice to as to if/when to
> bump the minimum versions.
> 
> 
> As a general rule, we don't want to be sufficiently bleeding edge to
> rule out in-use distros.  I have no idea if 4.06 is ok there, or whether
> it is too new.  Then again, the Ocaml components are strictly optional
> so it is perhaps less important.
> 
> Whatever happens WRT version, the configure change should occur before
> changes in the code which would fail on older versions.

Yes I would like to see the bump happen before applying a version of
this series too.

Wei.

> 
> ~Andrew