Bug #20872: Undefined RUBY_API_VERSION_* macros used in <ruby/backward/cxxanyargs.hpp>

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: ruby 3.4.0preview2 (2024-10-07 master 32c733f57b) +PRISM [x86_64-linux]
• Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

[hanazuki (Kasumi Hanazuki)]

I just noticed that C++ compilers warn for undefined RUBY_API_VERSION_MAJOR/RUBY_API_VERSION_MINOR macros in <ruby/backward/cxxanyargs.hpp> when preprocessing <ruby.h>.

% cat test.cpp
#include <ruby.h>

% clang++ -Wundef -I ~/.rbenv/versions/3.4.0-preview2/include/ruby-3.4.0+0 -I ~/.rbenv/versions/3.4.0-preview2/include/ruby-3.4.0+0/x86_64-linux -c test.cpp -o /dev/null
In file included from test.cpp:1:
In file included from /home/kasumi/.rbenv/versions/3.4.0-preview2/include/ruby-3.4.0+0/ruby.h:38:
In file included from /home/kasumi/.rbenv/versions/3.4.0-preview2/include/ruby-3.4.0+0/ruby/ruby.h:27:
In file included from /home/kasumi/.rbenv/versions/3.4.0-preview2/include/ruby-3.4.0+0/ruby/internal/anyargs.h:83:
/home/kasumi/.rbenv/versions/3.4.0-preview2/include/ruby-3.4.0+0/ruby/backward/cxxanyargs.hpp:540:6: warning: 'RUBY_API_VERSION_MAJOR' is not defined, evaluates to 0 [-Wundef]
#if (RUBY_API_VERSION_MAJOR * 100 + RUBY_API_VERSION_MINOR) >= 301
     ^
/home/kasumi/.rbenv/versions/3.4.0-preview2/include/ruby-3.4.0+0/ruby/backward/cxxanyargs.hpp:540:37: warning: 'RUBY_API_VERSION_MINOR' is not defined, evaluates to 0 [-Wundef]
#if (RUBY_API_VERSION_MAJOR * 100 + RUBY_API_VERSION_MINOR) >= 301
                                    ^
2 warnings generated.

The offending code was introduced in 01825e8bffd. The accompanying code comment says a deprecation warning should be emitted for some use-cases (passing ANYARGS function pointers to rb_define_method-series functions) with Ruby 3.x, which looks not working as intended for the current Ruby versions.

This seems effectively doing no harm but just disturbing for extension developers.

[nobu (Nobuyoshi Nakada)]

It looks no hurt to remove the conditional already.

[hanazuki (Kasumi Hanazuki)]

nobu (Nobuyoshi Nakada) wrote in #note-1:

It looks no hurt to remove the conditional already.

Ah, yes. That should be right.