Empty line around nesting blocks of the same indentation

I was a bit surprised with a colleague today when I learned that this was allowed by default:

def foo
  numbers = [1,2,3]
  numbers.map do |n|
    n+1
  end
end

as I don't allow myself to do that. There would be an empty line before the map block.

The logic, which is consistent with some other rules:

• There must be an empty line between a block that creates a new nesting context and something else at the same indent level.

(A nesting context being something that has different indentations inside of it)

Meaning:

# good
def foo
  numbers = [1,2,3]

  numbers.map do |n|
    n+1
  end
end

# bad
def foo
  numbers = [1,2,3]
  numbers.map do |n|
    n+1
  end
end

# bad: indent level changes, thus empty line is not needed
def foo
  numbers = [1,2,3]

  numbers.map do |n|
    n+1
  end

end

# bad
def foo
  numbers = [1,2,3]

  numbers.map! do |n|
    n+1
  end
  numbers.map do |n|
    n+2
  end
end

I apply this logic to any nesting context: modules, methods, blocks...

Have I missed something?

Start by reviewing the existing style-guide guidance on empty lines, nesting contexts, and blocks. Check the issue discussion for a decision on this proposed rule before changing anything. Done means documenting an agreed rule with consistent good and bad examples.