[yocto] admittedly simple questions about DISTRO_PN_ALIAS

[Paul Eggleton]

Hi Robert,

On Friday 09 January 2015 12:19:32 Robert P. J. Day wrote:
> reading dev manual here:
> 
> http://www.yoctoproject.org/docs/1.7/dev-manual/dev-manual.html#usingpoky-co
> nfiguring-DISTRO_PN_ALIAS
> 
> and first silly question -- what is the *purpose* of that variable? as
> in, what effect will it have on the eventual image? what difference
> will it make that, say, in fedora, a recipe would produce a package
> with a slightly different name? that section doesn't really explain
> that, as far as i can tell.
> 
>   next, i can see the collection of those settings in the file
> meta-yocto/conf/distro/include/distro_alias.inc, which has some odd
> lines. for example:
> 
> DISTRO_PN_ALIAS_pn-blktool = "Debian=blktool Mandriva=blktool"
> 
> what's the value of defining an alleged alias that simply has the same
> name? what is happening here?
> 
>   oh, and there's this amusing example:
> 
> DISTRO_PN_ALIAS_pn-bjam = "OpenSuSE=boost-jam Debina=bjam"
>                                               ^^^^^^
> 
> but since the recipe name is the *same*, i'm guessing that doesn't
> cause a problem.
> 
>   finally, the dev manual doesn't explain the meaning of lines like:
> 
> DISTRO_PN_ALIAS_pn-adt-installer = "Intel"
> DISTRO_PN_ALIAS_pn-alsa-state = "OE-Core"
> DISTRO_PN_ALIAS_pn-bdwgc = "OSPDT"
> 
>   in short, i can appreciate the *concept* of what might be happening
> in that short section, while still having no idea what value it has or
> how a developer might use it.

I'm not entirely sure how that section came to be written on its own, because 
it isn't at all useful and should probably be removed to save people 
confusion. DISTRO_PN_ALIAS is related to the mostly undocumented 
distrodata.bbclass that is supposed to help with managing recipe updates; I 
think the idea was to make a comparison with packages available in mainstream 
Linux distros but what it actually does for you in practice based on the code 
I can find doesn't seem to be very much. 

FYI, the reason distrodata has remained mostly undocumented is that we've had 
a plan to try to refactor and improve it for several years now, but it hasn't 
been as high a priority as we would have liked. There has been some renewed 
activity lately however - Aníbal Limón is working on the Recipe Reporting 
Service to replace what is up at packages.yoctoproject.org, and it should make 
it easier for people whose job it is to maintain recipes to track the current 
status with respect to upstream releases. It's being built on top of the 
OpenEmbedded Layer Index application.

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre