Strange Error

[applesnake]

require 'ffi'
require 'ffi/clang'
class TestStruct < FFI::Struct
  layout :a,:int,
         :b,:int,
         :c,:pointer
end

ERROR Message:

Traceback (most recent call last):
	6: from t-ffistruct.rb:3:in `<main>'
	5: from t-ffistruct.rb:4:in `<class:TestStruct>'
	4: from /usr/local/lib/ruby/gems/2.6.0/gems/ffi-1.11.1/lib/ffi/struct.rb:218:in `layout'
	3: from /usr/local/lib/ruby/gems/2.6.0/gems/ffi-1.11.1/lib/ffi/struct.rb:306:in `array_layout'
	2: from /usr/local/lib/ruby/gems/2.6.0/gems/ffi-1.11.1/lib/ffi/struct.rb:266:in `find_field_type'
	1: from /usr/local/lib/ruby/gems/2.6.0/gems/ffi-1.11.1/lib/ffi/struct.rb:272:in `find_type'
/usr/local/lib/ruby/2.6.0/mkmf.rb:1255:in `find_type': wrong number of arguments (given 1, expected 2+) (ArgumentError)

Remove: require 'ffi/clang', no error anymore.

[ioquatix]

Maybe the way you are using layout is wrong?

[take-cheeze]

Very strange issue.
Had some investigation and found the cause: mkmf
mkmf gem includes a module called MakeMakefile in Object class and is seems to polluting the global class.
And workaround you can take is to add following right after requiring ffi-clang:

module MakeMakefile
  undef find_type
end

Though I feel using mkmf in non build stage isn't a good idea so https://github.com/ioquatix/ffi-clang/blob/e59f5882c15d1ebdc077d871173a984c4a5fafad/lib/ffi/clang/lib.rb#L22 should be removed.

[ioquatix]

That makes sense, can you make a PR?

[take-cheeze]

Seems this workaround is fine too:

class Object
  undef find_type
end

[ioquatix]

Maybe we can fix mkmf?