Question about some Kconfig dependencies

[Xabier Oneca -- xOneca]

2013/10/30 Sarah Nadi <snadi at uwaterloo.ca>:
> On 13-10-29 06:55 AM, Denys Vlasenko wrote:
>>>
>>> Why does FEATURE_USERNAME_COMPLETION depend on
>>> FEATURE_TAB_COMPLETION in the libbb folder?
>>
>> Because username completion is a form of tab completion:
>> you type a partial username and press <tab> key.
>>
> You can build Busybox successfully by selecting FEATURE_USERNAME_COMPLETION
> without FEATURE_TAB_COMPLETION though (if you change the dependency in
> Kconfig, and select one without the other). So, would something crash at
> runtime, or is the dependency based on the meaning of both functionalities
> as you describe?
>
> Thanks for your feedback.
>
> Sarah
>
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Hello Sarah,

Well, the code enabled by FEATURE_USERNAME_COMPLETION is *inside* the
code enabled by FEATURE_TAB_COMPLETION.

Also, the user name completion function is only used on tab completion
function, so it must compile even if tab completion isn't enabled, and
if the username completion code were compiled. (I mean, it just isn't
used.)

Pseudocode:

if FEATURE_TAB_COMPLETION
_ if FEATURE_USERNAME_COMPLETION
__ function complete_username() { ... }
_ endif
_ function tab_completion() { ... complete_username() ... }
endif

The dependencies are not necessary in the sense that code won't break,
but it doesn't make sense to enable user name completion without
enabling tab completion (in fact, user name completion wouldn't be
enabled in the code).

Cheers,

--
Xabier Oneca_,,_