Re: [docs] [PATCH 5/6] dev-manual/multiconfig: improve the current doc

[Quentin Schulz <quentin.schulz@cherry.de>]

Hi Antonin,

On 2/12/25 1:49 PM, Antonin Godard wrote:
> Hi Quentin,
> 
> On Tue Feb 11, 2025 at 12:19 PM CET, Quentin Schulz wrote:
>> Hi Antonin,
>>
>> On 2/7/25 5:28 PM, Antonin Godard via lists.yoctoproject.org wrote:
[...]

>>> -   Here is an example showing the minimal statements needed in a
>>> -   configuration file for a "qemux86" target whose temporary build
>>> -   directory is ``tmpmultix86``::
>>> +   .. note::
>>>    
>>> -      MACHINE = "qemux86"
>>> -      TMPDIR = "${TOPDIR}/tmpmultix86"
>>> +      Whether the same temporary directory (:term:`TMPDIR`) can be shared will
>>> +      depend on what is similar and what is different between the
>>> +      configurations. Multiple :term:`MACHINE` targets can share the same
>>> +      :term:`TMPDIR` as long as the rest of the configuration is the same,
>>> +      multiple :term:`DISTRO` settings would need separate :term:`TMPDIR`
>>> +      directories.
>>> +
>>
>> I have zero experience with multiconfig, but I think the only case where
>> we should be able to share a TMPDIR is whenever all recipes but the ones
>> whose PACKAGE_ARCH is MACHINE_ARCH are the same for both machines (or do
>> not conflict, e.g. a different TUNE_PKGARCH for each machine). This
>> includes not overriding anything for a machine (e.g.
>> do_install:my-machine-a() or SRC_URI:append:my-machine-b, etc..; though
>> I believe this must require adding PACKAGE_ARCH = MACHINE_ARCH for those
>> recipes?). Overall, I guess this is a VERY niche corner case?
> 
> To be fair, I can hardly think of a use-case where you would use the same
> TMPDIR, and it doesn't seem to be the general use-case. This is why I moved that
> to a note, so the "proper" way is emphasized below.
> 
> Maybe someone more experienced can confirm your thoughts on this!
> 

Maybe we should simply not suggest it at all so people don't get ideas :)

Cheers,
Quentin