hello-gem/hello

This cop checks for unused method arguments.

Example:

# bad

def some_method(used, unused, _unused_but_allowed)
  puts used
end

Example:

# good

def some_method(used, _unused, _unused_but_allowed)
  puts used
end

This cop transforms usages of a method call safeguarded by a non nil check for the variable whose method is being called to safe navigation (&.).

Configuration option: ConvertCodeThatCanStartToReturnNil The default for this is false. When configured to true, this will check for code in the format !foo.nil? && foo.bar. As it is written, the return of this code is limited to false and whatever the return of the method is. If this is converted to safe navigation, foo&.bar can start returning nil as well as what the method returns.

Example:

# bad
foo.bar if foo
foo.bar(param1, param2) if foo
foo.bar { |e| e.something } if foo
foo.bar(param) { |e| e.something } if foo

foo.bar if !foo.nil?
foo.bar unless !foo
foo.bar unless foo.nil?

foo && foo.bar
foo && foo.bar(param1, param2)
foo && foo.bar { |e| e.something }
foo && foo.bar(param) { |e| e.something }

# good
foo&.bar
foo&.bar(param1, param2)
foo&.bar { |e| e.something }
foo&.bar(param) { |e| e.something }

foo.nil? || foo.bar
!foo || foo.bar

# Methods that `nil` will `respond_to?` should not be converted to
# use safe navigation
foo.to_i if foo

This cop checks for trailing comma in array and hash literals.

Example: EnforcedStyleForMultiline: consistent_comma

# bad
a = [1, 2,]

# good
a = [
  1, 2,
  3,
]

# good
a = [
  1,
  2,
]

Example: EnforcedStyleForMultiline: comma

# bad
a = [1, 2,]

# good
a = [
  1,
  2,
]

Example: EnforcedStyleForMultiline: no_comma (default)

# bad
a = [1, 2,]

# good
a = [
  1,
  2
]

This cop is designed to help upgrade to Ruby 3.0. It will add the comment # frozen_string_literal: true to the top of files to enable frozen string literals. Frozen string literals may be default in Ruby 3.0. The comment will be added below a shebang and encoding comment. The frozen string literal comment is only valid in Ruby 2.3+.

Example: EnforcedStyle: when_needed (default)

# The `when_needed` style will add the frozen string literal comment
# to files only when the `TargetRubyVersion` is set to 2.3+.
# bad
module Foo
  # ...
end

# good
# frozen_string_literal: true

module Foo
  # ...
end

Example: EnforcedStyle: always

# The `always` style will always add the frozen string literal comment
# to a file, regardless of the Ruby version or if `freeze` or `<<` are
# called on a string literal.
# bad
module Bar
  # ...
end

# good
# frozen_string_literal: true

module Bar
  # ...
end

Example: EnforcedStyle: never

# The `never` will enforce that the frozen string literal comment does
# not exist in a file.
# bad
# frozen_string_literal: true

module Baz
  # ...
end

# good
module Baz
  # ...
end

Checks that the equals signs in parameter default assignments have or don't have surrounding space depending on configuration.

Example:

# bad
def some_method(arg1=:default, arg2=nil, arg3=[])
  # do something...
end

# good
def some_method(arg1 = :default, arg2 = nil, arg3 = [])
  # do something...
end

This cop checks for the presence of method_missing without also defining respond_to_missing? and falling back on super.

Example:

#bad
def method_missing(name, *args)
  # ...
end

#good
def respond_to_missing?(name, include_private)
  # ...
end

def method_missing(name, *args)
  # ...
  super
end

This cop checks for unused method arguments.

Example:

# bad

def some_method(used, unused, _unused_but_allowed)
  puts used
end

Example:

# good

def some_method(used, _unused, _unused_but_allowed)
  puts used
end

This cops checks if empty lines around the bodies of classes match the configuration.

Example: EnforcedStyle: empty_lines

# good

class Foo

  def bar
    # ...
  end

end

Example: EnforcedStyle: emptylinesexcept_namespace

# good

class Foo
  class Bar

    # ...

  end
end

Example: EnforcedStyle: emptylinesspecial

# good
class Foo

  def bar; end

end

Example: EnforcedStyle: noemptylines (default)

# good

class Foo
  def bar
    # ...
  end
end

Use a guard clause instead of wrapping the code inside a conditional expression

Example:

# bad
def test
  if something
    work
  end
end

# good
def test
  return unless something
  work
end

# also good
def test
  work if something
end

# bad
if something
  raise 'exception'
else
  ok
end

# good
raise 'exception' if something
ok