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Subject: Re: [4/5] Coccinelle: put_device: Extend when constraints for two
 SmPL ellipses
To:     Julia Lawall <julia.lawall@lip6.fr>,
        Wen Yang <wen.yang99@zte.com.cn>
Cc:     Gilles Muller <Gilles.Muller@lip6.fr>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Michal Marek <michal.lkml@markovi.net>,
        Nicolas Palix <nicolas.palix@imag.fr>, cocci@systeme.lip6.fr,
        linux-kernel@vger.kernel.org, Yi Wang <wang.yi59@zte.com.cn>
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From:   Markus Elfring <Markus.Elfring@web.de>
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Date:   Tue, 14 May 2019 09:49:38 +0200
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>> Can you agree to any information which I presented in the commit messag=
e?

Do you find this description inappropriate?


>>> You don't need so many type metavariables.
>>
>> It seems that the Coccinelle software can cope also with my SmPL code a=
ddition.
>> You might feel uncomfortable with the suggested changes for a while.
>
> It's ugly.  Much more ugly than msg =3D

The clarification of this change reluctance might become more interesting.
I got convinced that there is a need for further software updates.


>> * Can it become required to identify involved source code placeholders
>>   by extra metavariables?
>
> I don't understand the question.

Wen Yang was planning a corresponding modification since 2019-02-19.
https://lore.kernel.org/cocci/201902191014156680299@zte.com.cn/
https://systeme.lip6.fr/pipermail/cocci/2019-February/005620.html

I got into the development mood to contribute another concrete update sugg=
estion
for an open issue in affected scripts for the semantic patch language.
Do you recognise the need for the extension of exclusion specifications he=
re?


>> * Would you like to clarify the probability any more how often the show=
n
>>   type casts will be identical?
>
> No idea about this one either.

I am curious if helpful ideas will be added also by other contributors.


> Basically, if you have T && T, the two T's have to be the same,

Such an expectation might be logical.


> and T is not pure.

This information triggers various communication difficulties.


> If you have T on two separate ...s then you are in the && case.

I agree to this view also according the application of two ellipses
in the SmPL rule =E2=80=9Csearch=E2=80=9D.


> If you have T in two branches of a disjunction or in two whens on the sa=
me
> ... you are in the || case.

It is clear that disjunctions will check code alternatives here.
The clarification of consequences around the interpretation of =E2=80=9Cty=
pe purity=E2=80=9D
might distract from the final solution.


How many (optional) type casts would we like to handle by the discussed
source code search approach?

Regards,
Markus