concurrent-ruby-ext: fix build on Darwin 32-bit

[barracuda156]

Fixes: #1063

[barracuda156]

For the record, this works neatly with Ruby 3.3, while Ruby 3.2 also needs -Wno-incompatible-pointer-types to be passed, otherwise this fails:

atomic_reference.c: In function 'ir_compare_and_set':
atomic_reference.c:83:57: error: passing argument 3 of 'OSAtomicCompareAndSwap32' from incompatible pointer type [-Wincompatible-pointer-types]
   83 |   if (OSAtomicCompareAndSwap32(expect_value, new_value, &DATA_PTR(self))) {
In file included from atomic_reference.h:9,
                 from atomic_reference.c:20:
/usr/include/libkern/OSAtomic.h:132:93: note: expected 'volatile int32_t *' {aka 'volatile int *'} but argument is of type 'void **'
  132 | bool    OSAtomicCompareAndSwap32( int32_t __oldValue, int32_t __newValue, volatile int32_t *__theValue );
      |                                                                           ~~~~~~~~~~~~~~~~~~^~~~~~~~~~
make: *** [atomic_reference.o] Error 1

make failed, exit code 2

[eregon]

Arguments should be explicitly casted to avoid the warning/error.

One problem though is we have no way to test macOS 32-bit, so it should be considered basically unsupported.

[barracuda156]

@eregon If you suggest a better fix, I can test that locally both on ppc and i386.

[eregon]

Suggested change

	if (OSAtomicCompareAndSwap32(expect_value, new_value, &DATA_PTR(self))) {
	if (OSAtomicCompareAndSwap32(expect_value, new_value, (VALUE*) &DATA_PTR(self))) {

Can you try this?
I think it should solve your warning on Ruby 3.2

[barracuda156]

Sure, I will try that, thank you.

[barracuda156]

Upd. No, it still fails if the error is not downgraded to warning with a flag.

[barracuda156]

I have still added (VALUE*) there and rebased to master.

[eregon]

Upd. No, it still fails if the error is not downgraded to warning with a flag.

Could you share the error output?
Does it work fine with the current state of this PR?

[eregon]

If it's still an error then probably we need to match the signature exactly:
(from the PR description)

  132 | bool    OSAtomicCompareAndSwap32( int32_t __oldValue, int32_t __newValue, volatile int32_t *__theValue );

So

if (OSAtomicCompareAndSwap32((int32_t) expect_value, (int32_t) new_value, (int32_t*) &DATA_PTR(self))) {

[barracuda156]

Sorry, I did not notice this. I will try it.

[eregon]

I'll merge this, even though that platform is not really supported since we can't test it in CI.
But the change looks safe and small enough, and you confirmed it works, so let's merge it.
EDIT: looks like it's not working yet? #1064 (comment)

[barracuda156]

@eregon It does work with a flag passed to downgrade error to a warning: https://github.com/macos-powerpc/powerpc-ports/blob/419651175e26d038a2c29040f1cae484426aeda0/ruby/rb-concurrent-ruby-ext/Portfile#L28-L30
Given this was the default before gcc14 and also that a lot of ports use it, and not only on old macOS, I think it is safe. The only “risk” is that someone tries to build it on the old macOS and fails to – but it is broken right now anyway.

[eregon]

Mmh, that's still not right then, could you try #1064 (comment) ?
That should emit no warning/error at all.

[barracuda156]

@eregon Yeah, that works now without adding a flag.

[eregon]

Great, could you update the PR to use that?

[barracuda156]

@eregon Updated