Re: [OE-core] [PATCH] selftest/imagefeatures/overlayfs: Always append to DISTRO_FEATURES

[Jacob Kroon <jacob.kroon@gmail.com>]

On 5/16/22 15:01, Quentin Schulz wrote:
> Hi Jacob,
> 
> On 5/16/22 14:52, Jacob Kroon wrote:
>> On 5/16/22 14:38, richard.purdie@linuxfoundation.org wrote:
>>> On Mon, 2022-05-16 at 13:43 +0200, Jacob Kroon wrote:
>>>> Hi Richard,
>>>>
>>>> On 5/16/22 13:28, Richard Purdie wrote:
>>>>> Using += unintentionally removes all over entries from 
>>>>> DISTRO_FEATURES and
>>>>
>>>> "over", you mean "other" ? If so, how is that possible ?
>>>
>>> I mean other, I'll fix the typo. It happens due to:
>>>
>>> meta-poky/conf/distro/poky.conf:DISTRO_FEATURES ?= 
>>> "${DISTRO_FEATURES_DEFAULT} ${POKY_DEFAULT_DISTRO_FEATURES}"
>>>
>>> which interacts badly with "+=" :(
>>>
>>> I'm not happy about the situation with variable interactions but still
>>> not entirely sure the best way to proceed.
>>>
>>
>> That is surprising to me. I tried this snippet in a Makefile:
>>
>> foo ?= bar1
>>
>>
>>
>> foo += bar2
>>
> 
> Same for Bitbake.
> 
> However:
> foo += bar2
> 
> foo ?= bar1
> 
> will return " bar2", while make returns "bar2" (note the missing leading 
> space).
> 
> The issue is where the ?= is located. If it is in a recipe, 
> configuration files need to use :append otherwise they will override ?= 
> (as configuration files are parsed before recipes).
> 

Right, I see. So the "+="-operator is behaving as expected, but in this 
case the order of the statements forces usage of the append-override :-/

Jacob