[PATCH v1] env: add w flags for net config in explicit write mode

[Heiko Schocher]

Hello Benjamin,

On 25.01.26 14:33, Benjamin ROBIN wrote:
> Hello Heiko,
> 
> On Sunday, January 25, 2026 at 2:03 PM, Heiko Schocher wrote:
>>> Users who enable CONFIG_ENV_WRITEABLE_LIST typically want full control
>>> over
>>> which environment variables are writable. The new default behavior
>>> introduced by your patch might not align with what all users expect or
>>> want.
>>>
>>> Would overriding the flags using CFG_ENV_FLAGS_LIST_STATIC not work in
>>> this
>>> case?
>>
>> Good question, I have to test... or may Adrian has already done
>> such tests...
> 
> Please test.

We will do.

> 
>> But looking into code.. if we add this variables in ENV_WRITEABLE_LIST
>> the results would be, that this variables are twice in ENV_FLAGS_LIST_STATIC
>>
>> include/env_flags.h
>>    87 #define ENV_FLAGS_LIST_STATIC \
>>    88         ETHADDR_FLAGS \
>>    89         NET_FLAGS \
>>    90         NET6_FLAGS \
>>    91         SERIAL_FLAGS \
>>    92         CFG_ENV_FLAGS_LIST_STATIC
>>
>> once through NET_FLAGS and once through CFG_ENV_FLAGS_LIST_STATIC
> 
> Yes, the variables with the flags would be declared twice.
>   
>> So, that is not good, and I think, code will find the first
>> entry, and parse it -> so it will not work.
> 
> What leads you to this assumption?
> 
> If you examine the code, you'll notice that:
>   - The env_attr_lookup() function returns the last entry.
>   - When iterating over the flags using env_attr_walk(), any previous attribute
>     flags are overridden by subsequent flag declarations.

Ah, thats the trick! If this is the case, I aggree, and we can
simply drop this patch!

> 
>> Should we instead in case CONFIG_ENV_WRITEABLE_LIST is enabled
>> only set/allow CFG_ENV_FLAGS_LIST_STATIC in ENV_FLAGS_LIST_STATIC ?
> 
> I haven't tested this myself, as I currently don't have a test environment
> available. Please test it, and if it doesn't work, the correct fix would be to
> ensure that any future flag declaration overrides previous ones.

We will test, thanks!

bye,
Heiko
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