Re: [cocci] Reconsidering application of selected SmPL isomorphisms

[Julia Lawall <julia.lawall@inria.fr>]

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On Mon, 25 Nov 2024, Markus Elfring wrote:

> Hello,
>
> I would like to clarify software development consequences also for
> a simple script variant for the semantic patch language (like the following).
>
>
> @show_questionable_checks@
> expression e1, e2;
> statement s1, s2;
> @@
>  if
>  (
> *!(e1 || e2)
>  )
>     s1
>  else
>     s2
>
>
> Questionable test result:
> Markus_Elfring@Sonne:/home/altes_Heim2/elfring/Projekte/Coccinelle/janitor> spatch --parse-cocci show_questionable_OR_checks2.cocci
> …
> (
>
> (
>
> (
> if (*!*(*e1 *|| *e2*))
> |
> if (*!*e1 *|| *e2)
> )s1 else s2
> |
> …
>
>
> I would interpret such data display in the way that the isomorphism “paren”
> was applied here.
> https://gitlab.inria.fr/coccinelle/coccinelle/-/blob/04f71e76b0857ca12ec7207b26368df78d2b57d4/standard.iso#L389
>
> I find the shown SmPL code transformation inappropriate at this place.
> Would we like to apply De Morgan's laws instead?
> https://en.wikipedia.org/wiki/De_Morgan%27s_laws
>
> Would we like to reconsider the application of the isomorphism for the switching
> of if/else branches accordingly?

Indeed, it looks wrong.

Thanks for the report.

julia