New candidate JEP: 357: Migrate from Mercurial to Git

[Mario Torre]

I think it should written in the "goals" that one goal is that the
workflow changes will be minimal and non disruptive of the current
workflow, this has been promised multiple times as part of project
Skara, so we should really write it down.

Cheers,
Mario

On Mon, Jul 15, 2019 at 8:53 PM Aleksey Shipilev <shade at redhat.com> wrote:
>
> On 7/15/19 7:54 PM, mark.reinhold at oracle.com wrote:
> > https://openjdk.java.net/jeps/357
>
> Unfortunately, this JEP only discusses the advantages, and does not discuss the disadvantages of
> performing this move.
>
> The disadvantages, off the top of my head:
>  *) Conversion takes time and effort for all projects, including those developed outside of
> mainline: Amber, Loom, Panama, Portola, Shenandoah, Valhalla to name a few;
>  *) Developers who are already quite constrained to deliver things with 6 months pace would have to
> re-adjust their workflows, some would need re-training to Git, many would have to accept the
> temporary productivity losses, and/or modify their delivery schedules;
>  *) Downstream builders would need to refit their pipelines after the move -- and there are lots of
> them;
>
> Additionally, not addressed:
>  *) Existing hgupdater links in JBS would have to be updated, or they would break;
>  *) External links to hg.o.j.n -- that were deemed to be permalinks to the JDK source code, perhaps
> with lots of wishful thinking involved -- would break;
>  *) There are improvements to Mercurial that can make the conversion advantages less appealing. For
> example, clonebundles that I pointed out multiple times over the year (and Mark promised to deliver,
> at OpenJDK Committers Workshop in February 2019) is still not enabled:
> https://bugs.openjdk.java.net/browse/JDK-8211383. Instead, we have "Alternatives: Keep using
> Mercurial" (sic!).
>  *) The claim that "There are many more tools for interacting with Git than Mercurial" look dubious.
> For the tools I use from that list: IntelliJ, NetBeans, Atom are supporting Mercurial as well.
>
> AFAIU, JEPs are supposed to capture the pros and cons, and provide extended background for
> discussion for the changes that have wide area of effect. Alas, the JEP 357 does not look to be in
> that state at the moment.
>
> --
> Thanks,
> -Aleksey
>


-- 
Mario Torre
Associate Manager, Software Engineering
Red Hat GmbH <https://www.redhat.com>
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