Incompatible with oj gem when running bundle install.

[huyhuynh-eh]

I'm using Macbook M3, OS Sonoma 14.4, ruby version is 2.7.8 , I'm facing this issue when run bundle install . I did install xcode version 15 , and using flag -- --with-cflags=-Wno-implicit-function-declaration . But the issue is remain the same. Can you help to resolve this issue. Thank you !

`Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

current directory: /Users/huyhuynh/.rvm/gems/ruby-2.7.8@2.7.8XXX/gems/oj-3.9.1/ext/oj

/Users/huyhuynh/.rvm/rubies/ruby-2.7.8/bin/ruby -I /Users/huyhuynh/.rvm/rubies/ruby-2.7.8/lib/ruby/2.7.0 -r ./siteconf20240310-16248-19xxpvp.rb extconf.rb

Creating Makefile for ruby version 2.7.8 on arm64-darwin23 <<<<<
checking for rb_time_timespec()... yes
checking for rb_ivar_count()... yes
checking for rb_ivar_foreach()... yes
checking for stpcpy()... yes
checking for rb_data_object_wrap()... yes
checking for pthread_mutex_init()... yes
creating Makefile

current directory: /Users/huyhuynh/.rvm/gems/ruby-2.7.8@2.7.8XXX/gems/oj-3.9.1/ext/oj
make "DESTDIR=" clean

current directory: /Users/huyhuynh/.rvm/gems/ruby-2.7.8@2.7.8XXX/gems/oj-3.9.1/ext/oj
make "DESTDIR="
compiling cache8.c
compiling circarray.c
compiling code.c
compiling compat.c
compiling custom.c
custom.c:376:23: error: incompatible function pointer types passing 'int (VALUE, VALUE, Out)' (aka 'int (unsigned long, unsigned long, struct _out )') to parameter of type 'int ()(VALUE, VALUE, VALUE)' (aka 'int
()(unsigned long, unsigned long, unsigned long)') [-Wincompatible-function-pointer-types]
rb_hash_foreach(obj, hash_cb, (VALUE)out);
^~~~~~~
/Users/huyhuynh/.rvm/rubies/ruby-2.7.8/include/ruby-2.7.0/ruby/intern.h:558:35: note: passing argument to parameter here
void rb_hash_foreach(VALUE, int ()(VALUE, VALUE, VALUE), VALUE);
^
custom.c:686:26: error: incompatible function pointer types passing 'int (ID, VALUE, Out)' (aka 'int (unsigned long, unsigned long, struct _out )') to parameter of type 'int ()(ID, VALUE, st_data_t)' (aka 'int
()(unsigned long, unsigned long, unsigned long)') [-Wincompatible-function-pointer-types]
rb_ivar_foreach(obj, dump_attr_cb, (VALUE)out);
^~~~~~~~~~~~
/Users/huyhuynh/.rvm/rubies/ruby-2.7.8/include/ruby-2.7.0/ruby/intern.h:986:35: note: passing argument to parameter here
void rb_ivar_foreach(VALUE, int ()(ID, VALUE, st_data_t), st_data_t);
^
2 errors generated.
make: *** [custom.o] Error 1

make failed, exit code 2`

[ohler55]

It looks like the latest compiler is more picky. Some of the ruby APIs have changed over the year ever so slightly. For example going from void* to VALUE. I can fix the ones in Oj but not the ones in ruby. I'm on macOS 14.2.1 and I have not run into that issue but I am also using Ruby 3.2. Have you tried moving to a more recent version of ruby? Ruby 2.7.0 came out in 2019 and while the 2.7.8 patch version was last year most of the code is still 5 years old. Are you restricted to ruby 2.7.x?

[ohler55]

Anyway, I'll update and see what needs to be fixed.

[ohler55]

Builds okay with Ruby 3.2. I'll try 2.7.8 next.

[ohler55]

Oj builds for me with macOS Sonoma 14.4, ruby version is 2.7.8. Could there be some oddness since you are building inside the .rvm/gems folder? Can you try pulling and building?

[ohler55]

Are you still having an issue building?

[huyhuynh-eh]

Hi I'm using cflag when bundle install new gem --with-cflags="-Wno-error=incompatible-function-pointer-types" , it resolved my problem.

[ohler55]

I'll keep that in mind if someone else has a similar issue in the future.

[stanhu]

FYI, this problem was fixed in oj v3.10.1 via 0d786fa6. I just upgraded to v3.16.3.

Notice the error above is complaining about the third parameter with the Out type:

custom.c:376:23: error: incompatible function pointer types passing 'int (VALUE, VALUE, Out)' 

That commit fixed the signature to have all parameters with the VALUE type.

clang 16 raises an error for incompatible function pointer types (https://discourse.llvm.org/t/clang-16-notice-of-potentially-breaking-changes/65562).