[oe] [meta-python] README: contradictory indications?

[Andrea Galbusera]

On Sun, Apr 29, 2018 at 5:22 PM, Khem Raj <raj.khem at gmail.com> wrote:
> On Sun, Apr 29, 2018 at 7:59 AM, Andrea Galbusera <gizero at gmail.com> wrote:
>> On Sat, Apr 28, 2018 at 10:03 PM, Khem Raj <raj.khem at gmail.com> wrote:
>>>
>>> On Thu, Apr 26, 2018 at 12:10 AM Andrea Galbusera <gizero at gmail.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> I see that README in meta-python contains conflicting information
>>>> about layer's dependencies. The introductory paragraph states that
>>>> "modules in this layer need to be independent of openembedded-core and
>>>> meta-openembedded/meta-oe", then a few lines below both of these
>>>> layers are listed within meta-python's dependencies.
>>>>
>>>> To me, looks like the sentence in the introduction does not hold true
>>>> and can be removed. If you can help clarify what the correct
>>>> information is, I can send a patch to fix the documentation bits.
>>>
>>>
>>> Usually it shoudl be just core layer
>>
>> That's not the case, at least out of the box. Without meta-oe in
>> bblayers bitbake complains with:
>>
>> ERROR: Layer 'meta-python' depends on layer 'openembedded-layer', but
>> this layer is not enabled in your configuration
>>
>> Then, would be ok to drop 'openembedded-layer' from
>> LAYERDEPENDS_meta-python in conf/layer.conf? Parsing-wise it seems of
>> no hurt...
>
> I think if there is a dependency on meta-oe that could be beyond
> parsing e.g. compiling
> a recipe might assume another recipe from meta-oe during compile,
> ideally packageconfig
> for such features would be ideal. We can validate the dependencies via
> building each recipe
> from meta-python without meta-oe in layermix.

Yep! Doing exactly that and already found some...

ERROR: Nothing PROVIDES 'libsmi' (but
/home/gizero/work/upstreaming/meta-openembedded/meta-python/recipes-devtools/python/python-snimpy_0.8.12.bb
DEPENDS on or otherwise requires it).
ERROR: Nothing PROVIDES 'zeromq' (but
/home/gizero/work/upstreaming/meta-openembedded/meta-python/recipes-devtools/python/python-pyzmq_14.7.0.bb
DEPENDS on or otherwise requires it)
ERROR: Nothing RPROVIDES 'python-pygobject' (but
/home/gizero/work/upstreaming/meta-openembedded/meta-python/recipes-devtools/python/python-pydbus_0.6.0.bb,
/home/gizero/work/upstreaming/meta-openembedded/meta-python/recipes-devtools/python/python-dbusmock_0.16.7.bb
RDEPENDS on or otherwise requires it)

I have no idea if it would be meaningful for some of them to support
disabling deps via PACKAGECONFIG... Would it make any sense building
python-pyzmq without zeromq? That said, recipes with deps outside of
core don't seem to be many: maybe it's still worth considering fixing
them to make their external deps optional. Otherwise, I guess we
should stay with current LAYERDEPENDS_meta-python and just fix the
README.

> It would be better to document whats actually happening in code even
> though it is less
> than ideal.

Could you elaborate? What do you mean exactly with "documenting in code" here?