Bug #6608
closedFile.join behavior
Description
Hello,
I would like to know if the current behavior of File.join is intended, and what should be its specification, especially on systems with File::ALT_SEPARATOR.
File.join adds '/' for joining if no separator is present:
File.join('a', 'b') # => "a/b"
And if a forward slash is present or two, it just acts the same:
File.join('a', '/b') or File.join('a/', 'b') # => "a/b" # => "a/b"
(These are expected)
But when a backward slash is present (= File::ALT_SEPARATOR), it seems it is kept only if it is on the right side or no other separator is present:
File.join('a', '\b') or File.join('a\', 'b') # => "a\b"
File.join('a/', '\b') # => "a\b"
but
File.join('a\', '/b') # => "a/b"
And it seems the right part is never touched, while the left part loses all its separators, unless there are none on the right side.
File.join('a//', '\b') # => "a\b"
File.join('a//', '//b') # => "a\//b"
File.join('a//', 'b') # => "a//b"
Ruby is usually giving only forward-slash paths (Dir.getwd) and accepts them only in some cases (Dir.glob).
I think conceptually File.join should remove all "" and replace them by "/", like File.expand_path does for example.
I guess this is not done for efficiency reasons.
But it also means it might produce not natural behavior:
Dir.glob(File.join('C:', '\WINDOWS', '')) == Dir.glob('C:\WINDOWS/') # => ["C:WINDOWS/system"] # sounds like a bug, isn't it?
but
Dir.glob(File.join('C:', '/WINDOWS', '*')) # => all files/dirs under C:/WINDOWS
The current RubySpec is a bit misleading in this regard: https://github.com/rubyspec/rubyspec/blob/master/core/file/join_spec.rb#L21-26