Re: [cocci] Searching for repeated source code with SmPL?

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

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On Sun, 12 May 2024, Markus Elfring wrote:

> > Your semantic patch needs to be:
> >
> > @display@
> > @@
> >  my_action(...);
> >  <+... when any
> > *my_action(...);
> >  ...+>
> >
> > Without that, a call to my_action is forbidden in the region matched by
> > the <+... ...+>.  Because any kind of dot thing matches the shortest path
> > between what comes before and what comes after (here the end of the function).
>
> Can the Coccinelle software inform better about the case that the shortest
> path constraint was “accidentally overlooked” in a SmPL script?
>
>
> There are further development challenges to consider.
> See also a corresponding transformation approach by the means of
> another tiny script for the semantic patch language:
>
> @adjustment@
> @@
>  my_action(
> -          ...
> +          0
>           );
>  <+... when any
> -my_action(...);
>  ...+>
>
>
> Test result:
> Markus_Elfring@Sonne:…/Projekte/Coccinelle/Probe> spatch use_one_test_call.cocci repeated_three_calls.c
> …
> previous modification:
>
>   <<< 0
> CONTEXT
>
> According to environment 0:
>
>
> current modification:
> MINUS
>
> According to environment 0:
>
>
> adjustment: already tagged token:
> C code context
> File "repeated_three_calls.c", line 4, column 12, charpos = 48
>   around = ')',
>   whole content =  my_action(2);
>
>
> Can the data processing be improved anyhow?

The current semantic pach allows the first my_action to match anywhere,
including the second my_action, third, etc.  So if you have changes in
both, then there will be contradictory changes to the code.

Probably you should start with ... when != my_action(...) to be sure to
get the first one.

julia