[yocto] RFC: Package exclusion

[Joshua Lock]

Apologies for the tardy reply. I like where you're going, usually I have
to disagree to reply swiftly. Sorry.

On Tue, 2011-05-03 at 17:00 +0100, Paul Eggleton wrote:
> Hi all,
> 
> As part of the 1.1 feature list I suggested a review of the 
> INCOMPATIBLE_LICENSE and COMMERCIAL* package exclusion mechanisms we have 
> within Poky. Below I've outlined my ideas and would appreciate any 
> comments/additions/corrections.
> 
> ==== Aims ==== 
> 
>  * Make error messages clear when user/dependencies have asked for something 
> to be built that can't be due to restrictions
> 
>  * Ensure that exclusion system is reliable

Solid.

> 
> ====  Proposed implementation ==== 
> 
>  1) Ensure all documentation of LICENSE field value syntax is clear, concise 
> and up-to-date (wiki and manual)
> 
>  2) Go through and audit all recipes LICENSE field values to ensure that they 
> all conform to the specifications. This includes making sure that | (package 
> may be used under one of a selection of licences) and & (recipe has mixed 
> licences that apply to the code base, so conditions of all must be observed) 
> are used correctly.
> 
>  3) bitbake/core changes:
> 
>  * LICENSE field checking must fully parse the field and understand the 
> difference between | and &, and must not e.g. mark Qt as being GPLv3 only.
> 
>  * Make the LICENSE validity checking more strict (given recipes have been 
> audited and rules are clear after above)
> 
>  * Don't exclude any recipes at parse time - simply record all excluded 
> recipes and their runtime provides in a blacklist which also includes flags 
> indicating the reason for blacklisting
> 
>  * Ensure all excluded licences in INCOMPATIBLE_LICENSE are valid (e.g. catch 
> GPL3 as apposed to GPLv3) - if not, error out
> 
>  * Check when calculating dependencies if anything is scheduled to be built 
> that is on the blacklist - if any are, gather all of them up and then stop and 
> list them in an error message along with reason and depchain for each one

This sounds like overlap with a task Scott Garman is set to work on
(Error handling in bitbake), let's make sure you guys are collaborating
here.
http://bugzilla.yoctoproject.org/show_bug.cgi?id=542


> 
>  * Check when constructing the rootfs if anything in the runtime provides 
> blacklist is going to be included - if so, error out
> 
> 
> Some further possible extensions:
> 
>  * Possibly apply similar logic to COMPATIBLE_MACHINE?
> 
>  * Replace COMMERCIAL* with some more generic exclusion mechanism that allows 
> the reason to be defined as part of the exclusion list?

Sounds reasonable, care to elaborate? Something like:

COMMERCIAL_LICENSE = "naughty packages from copyright hell"
PERL_PACKAGES = "packages I don't want to include because I dislike
Perl"
EXCLUDED_PATTERNS = "PERL_PACKAGES COMMERCIAL_LICENSE"

??

> 
>  * As a helper for non-en_US users, fail on parse if user defines any of the 
> *LICENSE* variables as *LICENCE*? (we definitely don't want the build to 
> continue and just ignore this as the user might not realise what has happened)

Darn tootin!

Looks like a good start, thanks Paul!

Cheers,
Joshua
-- 
Joshua Lock
        Yocto Build System Monkey
        Intel Open Source Technology Centre