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Alec Warner wrote:
> On Fri, Oct 3, 2008 at 5:09 PM, Zac Medico <zmedico@g.o> wrote:
> Hi everyone,
> 
> Please consider a new "eapi" profile configuration file that will
> designate the EAPI to which any package atoms within a given layer
> of the profile stack must conform. This will allow package managers
> to bail out with an informative error message if the user
> accidentally selects a profile containing an EAPI that is not
> supported by the currently installed package manager.
> 
>> Long Long Ago there was a conversation about versioning profiles; is
>> there some reason why you prefer the eapi method (which arguably has a
>> smaller scope) over full profile api versioning (PAPI?)

I'm not sure what the specific intentions of PAPI are, but the EAPI
approach that I've suggested is intended to enable different layers
of the stack to contain dependency atoms that conform to different
EAPIs. For example, the base profile could remain at EAPI 0 and
could thus be shared between some older profiles that conform to
EAPI 0 (at all layers) and some newer profiles that contain some
layers which require EAPI 1 or EAPI 2.

By allowing a mix of different layers with different EAPIs, the
intention is to promote code sharing since we can use a common base
profile between older and newer profiles, yet still be able to use
new EAPIs in newer profiles.

>> Arguably we could use both in the future as well.
> 
> In order to allow mixed EAPIs in the profiles, and to avoid having
> to configure the EAPI in every single layer, each directory of the
> profile stack should be able to either override or inherit the EAPI
> value that may have been defined in a previous layer of the profile
> stack. If no EAPI has been previously defined then it can be assumed
> to be 0.
> 
> The format of the configuration file can be very simple, containing
> only the EAPI value and nothing more. For example, a file containing
>  just a single "0" character, followed by a newline, could be
> created at profiles/base/eapi in order to explicitly declare that
> atoms in the base profile conform to EAPI 0. However, this
> particular declaration would be redundant since the base profile
> does not inherit from any other profile and therefore it's EAPI
> would be assumed to be 0 anyway.
> 
> Does this seem like a good approach? Are there any suggestions for
> improvements or alternative approaches?
> 
>> PAPI :)

Would PAPI provide the same benefits in terms of code sharing by
allowing layers with different PAPIs to be mixed?

- --
Thanks,
Zac
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