[gentoo-dev] when to use a function and an implementation use flag.

[gentoo-dev] when to use a function and an implementation use flag.

[Peter Hjalmarsson]

I took a look at qemu-kvm and found something I percieve as funny:
It had a gnutls use-flag, but no ssl useflag.

As I see it is I want ssl/tls support it should be sufficient to enable
USE="ssl" and let the maintainer of said ebuild decide which
implementation (if more then one) I am better off with and only care
about the USE="gnutls openssl nss" if i really think the maintainer is
wrong.

For qemu-kvm the problem is that there is only one implementation (i.e.
gnutls), and if I want to have ssl support I have to enable gnutls for
this package.

When I wrote a bug about this I got a rather short reply from maintainer
about pointing me to the policy about this.
Now I know there was a disscussion a while back about this on the
mailinglist, but google fails me to find it, looking into the Gentoo
Development Guide [1] it fails me too.

There is not a _single_ word about how to handle if there is only one
implementation, but two use flags for this (one for the function
provided - ssl - and one for the actual implementation - gnutls).

So I have a question:
Is there no policy about this?
If there is could someone please point me towards it and also it in that
case may be time to update the gentoo development guide.

[1]
http://devmanual.gentoo.org/general-concepts/use-flags/index.html#conflicting-use-flags

Re: [gentoo-dev] when to use a function and an implementation use flag.

[Petteri Räty]

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On 03/24/2010 08:30 PM, Peter Hjalmarsson wrote:

> For qemu-kvm the problem is that there is only one implementation (i.e.
> gnutls), and if I want to have ssl support I have to enable gnutls for
> this package.

In this case the ebuild should have only ssl use flag.

> When I wrote a bug about this I got a rather short reply from maintainer
> about pointing me to the policy about this.

Where did he point you to?

> So I have a question:
> Is there no policy about this?

The policy is that USE="ssl" controls whether to enable ssl support in
general. Then the specific use flags like gnutls and openssl control
what implementation to use if the package supports multiple.

USE="ssl" --> should always give you ssl support

> If there is could someone please point me towards it and also it in that
> case may be time to update the gentoo development guide.
> 
> [1]
> http://devmanual.gentoo.org/general-concepts/use-flags/index.html#conflicting-use-flags
> 

If you read the example code you see what I said is already done in the
example code.

Opened a bug for qemu-kvm:
http://bugs.gentoo.org/show_bug.cgi?id=311627

Opened a bug for repoman:
http://bugs.gentoo.org/show_bug.cgi?id=311629

Regards,
Petteri



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Re: [gentoo-dev] when to use a function and an implementation use flag.

[Doug Goldstein]

On Sat, Mar 27, 2010 at 9:44 AM, Petteri Räty <betelgeuse@gentoo.org> wrote:
> On 03/24/2010 08:30 PM, Peter Hjalmarsson wrote:
>
>> For qemu-kvm the problem is that there is only one implementation (i.e.
>> gnutls), and if I want to have ssl support I have to enable gnutls for
>> this package.
>
> In this case the ebuild should have only ssl use flag.
>
>> When I wrote a bug about this I got a rather short reply from maintainer
>> about pointing me to the policy about this.
>
> Where did he point you to?

I didn't point him anywhere. I merely asked him for a policy on this.
Because senseless changes in USE flags will require my 9 VM servers
will need to be tweaked around for a pointless USE flag change and I
don't need administrative burden for the sake of administrative
burden.

>
>> So I have a question:
>> Is there no policy about this?
>
> The policy is that USE="ssl" controls whether to enable ssl support in
> general. Then the specific use flags like gnutls and openssl control
> what implementation to use if the package supports multiple.

Again, this policy is stated but no one can point me to anything. The
closest thing to a "policy" is you sending a follow up e-mail to the
dev list to make this a policy.

-- 
Doug Goldstein

Re: [gentoo-dev] when to use a function and an implementation use flag.

[Alec Warner]

On Sat, Mar 27, 2010 at 11:06 PM, Doug Goldstein <cardoe@gentoo.org> wrote:
> On Sat, Mar 27, 2010 at 9:44 AM, Petteri Räty <betelgeuse@gentoo.org> wrote:
>> On 03/24/2010 08:30 PM, Peter Hjalmarsson wrote:
>>
>>> For qemu-kvm the problem is that there is only one implementation (i.e.
>>> gnutls), and if I want to have ssl support I have to enable gnutls for
>>> this package.
>>
>> In this case the ebuild should have only ssl use flag.
>>
>>> When I wrote a bug about this I got a rather short reply from maintainer
>>> about pointing me to the policy about this.
>>
>> Where did he point you to?
>
> I didn't point him anywhere. I merely asked him for a policy on this.
> Because senseless changes in USE flags will require my 9 VM servers
> will need to be tweaked around for a pointless USE flag change and I
> don't need administrative burden for the sake of administrative
> burden.

I have concerns with this which I will attempt to summarize below.

1) Traditional binary distributions have releases that take users over
these changes (dist-upgrade and similar processes.)
2) Gentoo has no releases, so 'annoying administrative changes' are
certainly more challenging, because it is difficult to apply them to
new machines and not old ones.
3) Cleanup changes such as the one proposed are good for the health of
Gentoo.  Consistency in flags actually makes it *easier* for users to
configure their systems.  Consistency in ebuild behavior makes it
*easier* developers to maintain ebuilds.
4) Not making changes because they may affect existing systems is
crap.  It holds the distribution back because everyone will always
pull this card out to veto major changes.

It would be interesting if we could make these changes less painful:

1) For this change, attempt to detect how users are using these flags
and migrate them to the new system.  This will likely be easy for the
80% case (/etc/portage/...) and hard for the 20% case (cross-compiles,
and other odd things involving ROOT.)
2) Defer changes like this to some kind of release date.  Write down
what you want to do somewhere.  At the prescribed time (once a [month,
year, quarter?]) apply all the changes to the tree and release GLEP 42
news items, changelogs, webpage stuff, forums posts, etc.
3) other crap I haven't thought of.

>
>>
>>> So I have a question:
>>> Is there no policy about this?
>>
>> The policy is that USE="ssl" controls whether to enable ssl support in
>> general. Then the specific use flags like gnutls and openssl control
>> what implementation to use if the package supports multiple.
>
> Again, this policy is stated but no one can point me to anything. The
> closest thing to a "policy" is you sending a follow up e-mail to the
> dev list to make this a policy.
>
> --
> Doug Goldstein
>
>