Why is Dir.children documented for Ruby 2.4.1?

[meineerde]

The Dir.children method was added to Ruby trunk with Feature #11302. It was however not backported to Ruby 2.4 yet. Attempting to use it results in a NoMethodError in Ruby.

However, the method documentation is added to the Ruby 2.4.1 documentation at https://ruby-doc.org/core-2.4.1/Dir.html#method-c-children. Why is this the case? The method is not part of Ruby 2.4 and is (as far as I can see) not mentioned in the source code.

This was also asked and investigated at https://stackoverflow.com/a/45719685/421705

[chrisarcand]

Indeed, Dir.each_child as well, and it's present in all 2.4.x documentation. Added here.

[meineerde]

Similarly, Hash#transform_keys was added to trunk in Feature #13583 but not (yet) to Ruby 2.4. See https://stackoverflow.com/a/46414193/421705

[eregon]

We noticed a similar issue in ruby/spec#483.
It seems the docs ruby for 2.4.0, 2.4.1 and 2.4.2 all use trunk to generate the html documentaion, while they should of course use the corresponding tags like v2_4_2.

Same issue as #80.
@zzak do you know who we should ping about this or where to open an issue for it?