Re: [gentoo-dev] Re: ssl vs openssl vs libressl vs gnutls USE flag foo

["Anthony G. Basile" <blueness@gentoo.org>]

On 10/28/15 7:16 AM, hasufell wrote:
> On 10/28/2015 07:23 AM, Ryan Hill wrote:
>> Agreed.  If there's one choice then "ssl" should be used.  openssl/libressl/etc
>> should really be considered sub-flags of ssl.

This is what I did with curl.  USE=ssl means one and exactly one ssl 
provider must be specified.  I suggested making it a model gentoo wide, 
but there were criticisms, I forget what, but the made sense to me at 
teh time.

>>
>> I really wish we had some way of specifying this to make things clearer to the
>> user, so they could see exactly how these flags interact with each other.
>> Something like (emerge -pv):
>>
> The problem here is that we introduced REQUIRED_USE foo for these cases
> which is again highly ambigous instead of making the PM aware that this
> is an actual sub-USE flag.

A properly designed sub-USE flag would be useful here and clearly better 
than our REQUIRED_USE.  I think REQUIRED_USE is fine for heterogeneous 
cases, but not when you have something like curl where you can either 
turn ssl on or off.  If it is off, nothing more needs to be specified, 
if it is on, then you must further specify one and exactly one ssl provider.

>
> This is outside of the scope of this thread, but there are already
> distros that have fixed this:
> 1. NixOS [0] with truly declarative configuration format, e.g. something
> like:
> packages.ssl.provider = openssl;
>
> or somesuch (just an example)
>
> 2. Exherbo partly [1] with providers syntax:
> */* providers: -openssl libressl
>
> and the exheres would then do something like:
> DEPENDENCIES="
>      build+run:
>          providers:openssl?  ( dev-libs/openssl:0 )
>          providers:libressl? ( dev-libs/libressl )
> "
>
> which is a lot cleaner than USE_EXPAND + REQUIRED_USE, which still can
> have arbitrary meanings.
>
> But NIH will prevent us from learning here I guess.
>
>
> [0] https://nixos.org/nixos/manual/
> [1] http://exherbo.org/docs/eapi/providers-and-virtuals.html
>


-- 
Anthony G. Basile, Ph.D.
Gentoo Linux Developer [Hardened]
E-Mail    : blueness@gentoo.org
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