Check newline in empty reference bracket on Layout/SpaceInsideReferenceBrackets

[r7kamura]

This is the reference bracket version of the following Pull Request:

• Check newline in empty hash brace literal on Layout/SpaceInsideHashLiteralBraces #11032

which will add the following rule about newline in empty reference bracket:

# bad
foo[
]

# good - EnforcedStyleForEmptyBrackets: no_space (default)
foo[]

# good - EnforcedStyleForEmptyBrackets: space
foo[ ]

---

Before submitting the PR make sure the following are checked:

• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.

[r7kamura]

I think this is a topic that should be handled by a separate Pull Request or Issue, but let me mention it.

There is not much consistency in the following cops about how they handle redundant spaces on EnforcedStyleForEmptyX: space case.

• Layout/SpaceInsideHashLiteralBraces
• Layout/SpaceInsideReferenceBrackets

# Layout/SpaceInsideHashLiteralBraces:
#   EnforcedStyleForEmptyBraces: space

# bad
foo = {}

# good
foo = { }
foo = {    }

# Layout/SpaceInsideReferenceBrackets:
#   EnforcedStyleForEmptyBrackets: space

# bad
foo[]
foo[    ]

# good
foo[ ]

In other words, there is ambiguity as to whether the opposite of "space" is "any spaces" or "only one space".

My personal opinion is that the Layout/SpaceInsideReferenceBrackets rule is preferable, so I think that this is more of Layout/SpaceInsideHashLiteralBraces thing that should be fixed. What do you think?

[bbatsov]

My personal opinion is that the Layout/SpaceInsideReferenceBrackets rule is preferable, so I think that this is more of Layout/SpaceInsideHashLiteralBraces thing that should be fixed. What do you think?

Agreed. space should mean exactly one space. Perhaps we should have named this single_space, but that ship has sailed.