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Subject: Re: [v2] Coccinelle: Testing SmPL constraints
To:     Julia Lawall <julia.lawall@lip6.fr>, cocci@systeme.lip6.fr
Cc:     Wen Yang <wen.yang99@zte.com.cn>, Yi Wang <wang.yi59@zte.com.cn>,
        Gilles Muller <Gilles.Muller@lip6.fr>,
        Nicolas Palix <nicolas.palix@imag.fr>,
        Michal Marek <michal.lkml@markovi.net>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        linux-kernel@vger.kernel.org
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From:   Markus Elfring <Markus.Elfring@web.de>
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Date:   Sat, 29 Jun 2019 21:30:53 +0200
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> Please actually try things out before declaring them to be useless.

This feedback provides also another opportunity for collateral evolution
in some directions. I am curious on how involved uncertainty can be fixed =
around
possibly different interpretation for provided software functionality.

The SmPL construct =E2=80=9C... when =E2=80=A6=E2=80=9D is mentioned in an=
 area (of the section
=E2=80=9CBasic transformations=E2=80=9D in the software documentation) whi=
ch is introduced with
the wording =E2=80=9CThe grammar for the minus or plus slice of a transfor=
mation is
as follows:=E2=80=9D.
https://github.com/coccinelle/coccinelle/blob/c6d7554edf7c4654aeae4d33c3f0=
40e300682f23/docs/manual/cocci_syntax.tex#L1033

I got the impression that the corresponding meaning is not explained in th=
is
information source so far.
The published example =E2=80=9CReference counter: the of_xxx API=E2=80=9D =
can be interesting
then to some degree for the explanation of the discussed development effor=
ts.
https://github.com/coccinelle/coccinelle/blob/175de16bc7e535b6a89a62b81a67=
3b0d0cd7075c/docs/manual/examples.tex#L320

If the available application documentation is still too limited (and incom=
plete
because it is also work in progress), it is probably usual that SmPL code
occasionally tries to express expectations which are not covered by an evo=
lving
software implementation.
How would you like to improve the situation further?

* Is it certain that a search is performed only for the source code =E2=80=
=9Cx =3D=3D NULL=E2=80=9D
  (and corresponding isomorphisms) by the SmPL constraint =E2=80=9Cwhen !=
=3D true=E2=80=9D
  (after a successful null pointer check was detected in this use case)?

* Would you like to test any functionality which should work in different =
ways
  than you might see from the original OCaml source code?
  https://github.com/coccinelle/coccinelle/issues/134

Regards,
Markus