rb_file_dirname return wrong encoding string when dir is "."
When File.dirname()'s value is ".", the value is wrong encoded.
#2 [ruby-core:56560] Updated by firstname.lastname@example.org (贾 延平) about 4 years ago
The rb_file_dirname should not return diffrent encoding string value just because the string's content diffrent.
And some other function like rb_file_expand_path will return the value with the input paramter's incoding,and the result is not 7bit string.