Empty `with_them` definitions without `where` are misleading

[splattael]

Proposed solution

The following code does not run any examples because with_them is defined a different example group and it does not any where definitions.

describe 'empty' do
  where(:x) { [1] }

  describe 'another scope' do # !!! NOTE THIS EXTRA CONTEXT!!
    with_them do
      it 'works' do

      end
    end
  end
end

# 0 examples, 0 failures

Refs https://gitlab.com/gitlab-org/gitlab/-/issues/430870

Proposed solution

Because RSpec::Parameterized support definition of where/with_them in any order it's not straightforward to disallow the mentioned behavior (with_them without any where definitions).

I see the following options:

1. Emit a warning whenever with_them is defined before any where definition.
2. Disallow definition of with_them before where definition. This is potentially a BREAKING CHANGE.

Related but out of scope

• Disallow or warn about multiple where definitions. Currently, the latter wins without any warning.
• Disallow or warn about multiple with_them definitions. I am unsure about the use-case.

[splattael]

#9 to emit warnings when where was redefined or with_them was used before where was defined.