On Tue, Nov 9, 2021 at 10:28 AM Petr Nechaev <
[email protected]> wrote:

> Hi All,
>
>  I would also emit a (switchable on / off) warning for VAR_append  and
> VAR:append without a space when VAR contains spaces already i.e.:
>
> VAR = "opt1 opt2"
> VAR:append = "opt3"  --> warning
>

I was just going to comment with the same idea. Much earlier in my OE
journey, this bit me often and was a source of confusion.


> VAR2 = "--I-have-super-long-custom-option-flag"
> VAR2:append = "-and-short-also"  --> NO warning
>
> This should cause very little false warnings.
>
> ---
> Petr
>
>
> On Tue, Nov 9, 2021 at 8:15 PM Quentin Schulz <[email protected]> wrote:
>
>> Hi Richard,
>>
>> On November 9, 2021 4:15:16 PM GMT+01:00, Richard Purdie <
>> [email protected]> wrote:
>> >Hi All,
>> >
>> >I shared a patch on the bitbake mailing list to make some syntax generate
>> >warnings, specifically things of the form:
>> >
>> >XXX_append += "YYY"
>> >XXX_prepend += "YYY"
>> >XXX_remove += "YYY"
>> >
>>
>> Using the old syntax :D?
>>
>> >and the ?=, =+, .= and =. variants. This also covers variants with
>> overrides in
>> >there too. It would basically mean that you need to use "=" with the
>> append
>> >operator and friends.
>> >
>> >We found one reference of that use in OE-Core and one in meta-intel.
>> There are
>> >others in other layers but the usage isn't that widespread.
>> >
>> >Why should we warn against this? The += usage in particular is sometimes
>> used to
>> >add a space so:
>> >
>> >XXX_append += "YYY"
>> >
>> >and
>> >
>> >XXX_append = " YYY"
>> >
>> >are equivalent but this is more of an accident rather than a specific
>> bitbake
>> >design. It is extremely confusing to new users and has been complained
>> about
>> >before as an issue effecting usability. New users often think that +=
>> will stack
>> >the append strings much like += does on a normal variable but that is
>> not the
>> >case and can lead to confusion.
>> >
>> >I'm been looking at ways we can simplify without hurting functionality
>> and
>> >having this slightly obscure usage doesn't really seem to help much. If
>> we agree
>> >to do this, I would make it an error in due course after users have seen
>> the
>> >warnings for a while. I'd probably want to do that before the LTS next
>> year.
>> >
>>
>> I'm all for removing potential areas of confusion, so +1.
>>
>> On that topic, if I'm not mistaken, the same applies to:
>>
>> FOO:.*{append, prepend, remove}:.*{append,prepend,remove}
>> ? Basically it does not make much sense to have (any) two of append,
>> prepend, remove as overrides of the same variable (on the same line).
>>
>> Cheers,
>> Quentin
>>
>> >Cheers,
>> >
>> >Richard
>> >
>> >
>> >
>> >
>>
>>
>>
>>
> 
>
>
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