[OE-core] [RFC PATCH 1/1] classes/whitelist: add class to allow whitelisting recipes from a layer

[Randy MacLeod]

On 2015-08-24 07:02 AM, Paul Eggleton wrote:
> On Friday 21 August 2015 11:45:06 Richard Purdie wrote:
>> On Wed, 2015-08-19 at 14:34 +0100, Paul Eggleton wrote:
>>> Allow restricting recipes brought from a layer to a specified list. This
>>> is similar in operation to blacklist.bbclass, but instead specifies a
>>> per-layer whitelist of recipes (matched by BPN) that are able to be
>>> built from the layer - anything else is skipped. This is potentially
>>> useful where you want to bring in a select set of recipes from a larger
>>> layer e.g. meta-oe.
>>>
>>> Implements [YOCTO #8150].
>>>
>>> Signed-off-by: Paul Eggleton <paul.eggleton at linux.intel.com>
>>> ---
>>>
>>>   meta/classes/whitelist.bbclass | 28 ++++++++++++++++++++++++++++
>>>   1 file changed, 28 insertions(+)
>>>   create mode 100644 meta/classes/whitelist.bbclass
>>
>> I should go on record as having some pretty strong reservations about
>> this from a philosophical standpoint.
>>
>> Why? I think its going to encourage behaviours which will result in a
>> decrease in layer quality, particularly for meta-oe.
>>
>> Taking a simple example, today if someone breaks parsing in meta-oe, its
>> quickly known about and multiple people can see and resolve the issue.
>> Once people start using this class, many users will simply never
>> see/care about parsing breakage in less maintained parts of the layer.
>>
>> I appreciate Martin will likely notice, however this shouldn't Martin's
>> sole responsibility.
>>
>> Since people's focus will be on to narrow parts of the layer, we'll
>> start to see islands which are well maintained/used and islands which
>> are not. Worse, just looking at the layer, we won't be able to tell
>> which is which.
>>
>> I'm nervous about anything which pushes responsibility onto already
>> overloaded maintainers and encourages behaviour which is a net loss on
>> "quality".
>>
>> I've talked to several significant users and they all "love" the idea of
>> this class and plan to adopt it ASAP over existing tools like
>> combo-layer. I therefore can't see much advantage of not merging the
>> class as people are going to use it regardless.
>
> I appreciate the concern, but I have to be honest, I don't see this as being a
> problem with this class per se, for a couple of reasons:
>
> 1) People already feel the need to be selective in some way about the recipes
> they pull from larger layers such as meta-oe - whether they do it by using
> combo-layer, this class, git-filter-branch or simply by copying the recipes
> they want into their own layers. Using the whitelist class has one advantage
> over all the rest for the simple filtering case - you are always using the
> recipes from upstream. (OK, with combo-layer you probably are, but here it's
> direct.) Besides, even if people aren't doing any active filtering on the
> layer, they almost certainly aren't building the entire thing in any case - so
> can we really say they are testing it now?
>
> 2) Responsibility - it's great when people do report issues they find, but we
> shouldn't need to rely on people randomly coming across an issue in order to
> find it, we should be testing it ourselves. The job of maintaining the quality
> of layers rests with us - i.e. the people who are involved in maintaining the
> layers and developing the tools needed to do so. Martin does regular builds
> with a variety of layers as do others. If it's simply parse checking that we
> feel we are losing, it would be trivial to add extra regular checks; if
> nothing else, the layer index is parsing every recipe in almost every public
> layer every three hours; with a little extra work we could log and expose the
> results of that through the interface. (Am I volunteering to do this? Sure, as
> it'll probably be on my own time I can't promise to do it soon, but I will get
> to it if nobody else does first.)


Makes sense to me. I don't see the whitelist.bbclass in master-next yet.
Are you just waiting for the linux-4.1 and gcc-5.2 to go in?

../Randy

>
> Cheers,
> Paul
>


-- 
# Randy MacLeod. SMTS, Linux, Wind River
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