On Tue, Aug 30, 2022 at 11:12:24PM +0200, Johannes Schindelin wrote:

On Tue, 30 Aug 2022, Phillip Wood wrote:

quoted

I wonder if they would be interested in fixing the parsing bug we found
with Peff's UNUSED() series.

Could you point me to the relevant mail? I am sure that I can come up with
an MCVE that will help them pinpoint the bug and fix it as quickly as they
did with this here bug.

It's the sub-thread starting here:

  https://lore.kernel.org/git/220825.86ilmg4mil.gmgdl@evledraar.gmail.com/ (local)

I tried to put together a minimal example, which would be something
like:

  $ cat foo.c
  void old_function(int);
  void new_function(int);
  
  #if defined(__GNUC__)
  #define UNUSED(var) UNUSED_##var __attribute__((unused))
  #else
  #define UNUSED(var) UNUSED_##var
  #endif
  
  void foo(int UNUSED(bar), int x)
  {
  	old_function(x);
  }


  $ cat foo.cocci
  @@
  expression E;
  @@
  -old_function(E)
  +new_function(E)

but to my frustration, it actually works! If you add --verbose-parsing
to the spatch command, you can see it complaining about some of the
parsing. And it produces wrong outputs in the real-world with our actual
unused.cocci file. I suspect the example semantic patch might just need
to be a little more complicated.

-Peff