From: "ylecuyer (Yoann Lecuyer) via ruby-core" <ruby-core@...>
Date: 2024-04-29T12:48:41+00:00
Subject: [ruby-core:117737] [Ruby master Bug#20451] Bad Ruby 3.1.5 backport causes fiddle to fail to build

Issue #20451 has been updated by ylecuyer (Yoann Lecuyer).


Additional information:

From fiddle extconf:

``` ruby
case
when $mswin, $mingw, (libffi_version && (libffi_version <=> [3, 2]) >= 0)
  $defs << "-DUSE_FFI_CLOSURE_ALLOC=1"
when (libffi_version && (libffi_version <=> [3, 2]) < 0)
else
  have_func('ffi_closure_alloc', ffi_header)
end
```

and closure.c

```c
#if USE_FFI_CLOSURE_ALLOC
    result = ffi_prep_closure_loc(pcl, cif, callback,
		(void *)self, cl->code);
#else
    result = ffi_prep_closure(pcl, cif, callback, (void *)(data->self));
    cl->code = (void *)pcl;
    i = mprotect(pcl, sizeof(*pcl), PROT_READ | PROT_EXEC);
    if (i) {
	rb_sys_fail("mprotect");
    }
#endif
```

With libffi > 3.2 it compiles without any issue (I tried with 3.4.4) and with older version there is the error described (test with 3.1.0)


----------------------------------------
Bug #20451: Bad Ruby 3.1.5 backport causes fiddle to fail to build
https://bugs.ruby-lang.org/issues/20451#change-108144

* Author: Bo98 (Bo Anderson)
* Status: Open
* ruby -v: 3.1.5p252
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
Ruby 3.1.5 shipped with the following backport: https://github.com/ruby/ruby/commit/84f2aabd272a54e79979795d2d405090704a1d07

However this backport directly breaks the build:

``` 
closure.c:279:60: error: use of undeclared identifier 'data'
    result = ffi_prep_closure(pcl, cif, callback, (void *)(data->self));
                                                           ^
```

The original commit (https://github.com/ruby/fiddle/commit/2530496602) was updating the second branch to match the change in the first branch a couple lines up. However that change in the other branch does not exist in Ruby 3.1. The commit in question requires a previous commit of https://github.com/ruby/fiddle/commit/81a8a56239973ab7559229830a449d201955b494.

The backport should either be reverted or an other commit should also be backported. Note that these commits were in a series of many commits made to fix an upstream issue https://github.com/ruby/fiddle/issues/102 so I cannot vouch whether or not the two commits are sufficient to fix the originally reported issue.




-- 
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