bug#45836: [PATCH] services: Let cups-service-type reuse base lp group.

["Ludovic Courtès" <ludo@gnu.org>]

Hi,

Leo Prikler <leo.prikler@student.tugraz.at> skribis:

>> > diff --git a/gnu/system/shadow.scm b/gnu/system/shadow.scm
>> > index 0538fb1a24..7c57222716 100644
>> > --- a/gnu/system/shadow.scm
>> > +++ b/gnu/system/shadow.scm
>> > @@ -321,13 +321,13 @@ of user '~a' is undeclared")
>> >  <user-group> objects.  Raise an error if a user account refers to
>> > a undefined
>> >  group."
>> >    (define accounts
>> > -    (filter user-account? accounts+groups))
>> > +    (delete-duplicates (filter user-account? accounts+groups)
>> > eq?))
>> >  
>> >    (define user-specs
>> >      (map user-account->gexp accounts))
>> >  
>> >    (define groups
>> > -    (filter user-group? accounts+groups))
>> > +    (delete-duplicates (filter user-group? accounts+groups) eq?))
>> 
>> Why use ‘eq?’?  I’d use ‘equal?’, but note that <user-account>
>> records
>> cannot necessarily be compared with ‘equal?’ because of the thunked
>> ‘home-directory’ field (‘equal?’ is meaningless for procedures).
> My personal reasoning (and perhaps a rather strong opinion) is, that it
> is an error to add duplicate users even if they happen to be equal?. 
> eq? is only provided as a way out for the specific case of services,
> that need to do so for safety reasons – e.g. cups to not allow
> overriding of the lp group if it has been removed from the OS groups
> for whichever reason.

Ah I see, makes sense to me!

Thanks,
Ludo’.