Ruby

I think both IO#each and StringIO#each behavior is wrong when combining nil with chomp. My opinion is that a nil separator means there is no separator at all, and therefore chomp should either raise an error or be ignored if nil is the separator. Assuming that ignoring chomp is desired behavior for nil separator, it follows:

• IO#each behavior for nil and chomp with a limit is correct. However, IO#each for nil and chomp without a limit is not, since it removes a final line separator.

• StringIO#each behavior for nil and chomp is wrong, regardless of whether a limit is used.

This issue is related to String#each_line, but the nil and chomp combination there is handled correctly, not removing any characters (it doesn't support limit).

Note that Ruby has current tests for the IO#each behavior for nil and chomp without limit removing the trailing line separator. So the current behavior for that is definitely expected, though I consider it undesirable.

I've added PRs for Ruby (https://github.com/ruby/ruby/pull/5959) and StringIO (https://github.com/ruby/stringio/pull/28) for this.

We discussed this at the dev meeting, and @matz (Yukihiro Matsumoto) agreed with @jeremyevans0 (Jeremy Evans).