Subject: Re: bug#59423: Invalid 'location' field generated in dovecot configuration

From: Maxim Cournoyer <[email-masked]>
Date: Fri, 02 Dec 2022 22:05:12 -0500

Hi Ludovic,

Ludovic Courtès <[email-masked]> writes:

> Ludovic Courtès <[email-masked]> skribis:
>
>> Maxim Cournoyer <[email-masked]> skribis:
>
> [...]
>
>>> No :-).  I meant why do we even set a default accessor for the *source
>>> location* information (in the (gnu service configuration) macros); it's
>>> that one that doesn't seem to get used (or I'm blind to it!), at least
>>> via this accessor.  If it's not strictly necessary, we can stop
>>> producing it, and that would solve the problem.
>>
>> Like I wrote, I think it’s necessary, even if not used now.
>
> To complement this answer: key high-level record types usually have a
> ‘location’ field: <package>, <channel>, <mapped-device>, <file-system>,
> <service-type>, etc.  The rationale is that it allows us to report
> accurate location info for errors and warnings, to jump to their
> definition, and so on.
>
> For configuration records this is not a common pattern, but the
> rationale holds.  ‘zabbix-front-end-config’ uses the ‘%location’ field,
> but it seems to be the only one so far.

Thanks for this extra bit of information and for spotting this usage.  I
think "location" is likely to conflict for the general purpose
'define-configuration' generated records, so I've renamed the "location"
*accessor* to "source-location".

In the near future I want to migrate more service configurations to the
'define-configuration' machinery, to benefit from its useful
self-validating property.  For now I wouldn't feel at ease doing so
unless raw record matching (not yet using 'match-record') works the same
way, since we still have many occurrences making use of that (often via
match-lambda).  For that reason, I prefer to not revert the record
layout until we've gotten rid of all the match-lambda matching record
fields directly (which will take some time).

I've applied the rename fix to master.

-- 
Thanks,
Maxim