Re: [OE-core] [PATCH 1/7] scripts/oe-setup-builddir: add a check that TEMPLATECONF is valid

[ChenQi <Qi.Chen@windriver.com>]

On 9/14/22 14:39, Alexander Kanavin wrote:
> On Wed, 14 Sept 2022 at 07:49, ChenQi <Qi.Chen@windriver.com> wrote:
>> I'm reluctant to agree that this is like machine and distro, because
>> it's a hard requirement that machine and distro definitions be under
>> some layer, otherwise how can bitbake get info about it? But
>> TEMPLATECONF seems to be a different case, it could be everywhere
>> because it's used by the project setup script.
>>
>> In our case, the TEMPLATECONF is <project_dir>/config/, and layers are
>> <project_dir>/<layer>/. This directory hierarchy has been working for
>> years until recent changes.
>>
>> Do you think such directory hierarchy makes sense? How about we deleting
>> such check if there's no strong technical reason to do so? By 'strong
>> technical reason', I mean that some codes in oe-core are written based
>> on this assumption (this is the part I'm sure about).
> Again, it's not about only code. It's about humans too: we benefit
> from having things where we expect them to be.

$TEMPLATECONF/bblayers.conf.sample has a list of layers. These layers 
may have dependencies on each other or they may not. Which layer do you 
think should this TEMPLATECONF locate?

TEMPLATECONF, by its nature, is a project setup variable. It logically 
does not belong to any layer.

Why would people expect some project level variable to point to some 
directory under a layer?


> If your templates are
> in meta-layer/conf/templates/ you do not have to document, explain or
> support this;

Again, why this meta-layer should have knowledge about the whole 
project? It should be the project that has knowledge about layer, not 
the other way around.


> anyone new to the project will simply pick this up from
> prior experience or official documentation.

When users see a file in a layer that refers to other layers which this 
layer does not depend on and not been dependent upon, they may ask why.


>
> That said, there is already code that makes this assumption too: both
> 'bitbake-layers save-template-conf' and upcoming 'oe-setup-build' (the
> patch was sent for review here) consider only
> meta-layer/conf/templates.

Give it a second thought.

> I have to ask the same question to you: is there a strong technical
> reason that you cannot move the templates to the new standard
> location?

Yes. The bblayers.conf.sample is generated dynamically according to 
project setup.

That said, I could of course create a useless layer that does nothing 
but only holds these sample files to satisfy this sanity check. But I do 
think this sanity check is logically wrong.

Again, project contains layers, project setup could choose to use layers 
the project wants. Forcing a project level variable to point to a 
location under a layer is not reasonable.

Regards,

Qi


> Alex