Trust final fields in records

[John Rose]

On Jun 15, 2020, at 2:37 AM, Andrew Haley <aph at redhat.com> wrote:
> 
> On 12/06/2020 17:56, Brian Goetz wrote:
> 
>> If we make this change when records exit preview, this will catch
>> maintainers of these frameworks unaware — things will just start
>> breaking when their clients use records.  But if we give them a
>> grace period (e.g., lock it down in 17), we need to ensure that
>> they’ll use that time effectively,
> 
> Has this ever happened? What seems to have happened instead is that
> people complain bitterly about "access will be disabled in the next
> release" warning messages, do nothing, then complain even louder when
> access really gets disabled. Maybe I'm gitting jaundiced...

Under the assumption that *some* people will move on this
only when forced to move, a grace period buys nothing for
*those* people.  It’s not like we are changing an existing
behavior; since records are new, the grace period does not
apply to people who have built records in good faith and
need time to adjust.  In fact, if we give a grace period *now*
for the slow-footed “make me change” people, we might
well have to give *another* grace period to the more reasonable
people that adopted records in the preview.

I say, tighten the clamps now, when it hurts only a few
people.  No grace period today.

— John