Use def with parentheses when there are parameters. Open
def self.from_omniauth auth, current_user = nil
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Checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.
Regardless of style, parentheses are necessary for:
- Endless methods
- Argument lists containing a
forward-arg
(...
) - Argument lists containing an anonymous rest arguments forwarding (
*
) - Argument lists containing an anonymous keyword rest arguments forwarding (
**
) - Argument lists containing an anonymous block forwarding (
&
)
Removing the parens would be a syntax error here.
Example: EnforcedStyle: require_parentheses (default)
# The `require_parentheses` style requires method definitions
# to always use parentheses
# bad
def bar num1, num2
num1 + num2
end
def foo descriptive_var_name,
another_descriptive_var_name,
last_descriptive_var_name
do_something
end
# good
def bar(num1, num2)
num1 + num2
end
def foo(descriptive_var_name,
another_descriptive_var_name,
last_descriptive_var_name)
do_something
end
Example: EnforcedStyle: requirenoparentheses
# The `require_no_parentheses` style requires method definitions
# to never use parentheses
# bad
def bar(num1, num2)
num1 + num2
end
def foo(descriptive_var_name,
another_descriptive_var_name,
last_descriptive_var_name)
do_something
end
# good
def bar num1, num2
num1 + num2
end
def foo descriptive_var_name,
another_descriptive_var_name,
last_descriptive_var_name
do_something
end
Example: EnforcedStyle: requirenoparenthesesexceptmultiline
# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.
# bad
def bar(num1, num2)
num1 + num2
end
def foo descriptive_var_name,
another_descriptive_var_name,
last_descriptive_var_name
do_something
end
# good
def bar num1, num2
num1 + num2
end
def foo(descriptive_var_name,
another_descriptive_var_name,
last_descriptive_var_name)
do_something
end
Missing frozen string literal comment. Open
# == Schema Information
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Helps you transition from mutable string literals
to frozen string literals.
It will add the # frozen_string_literal: true
magic comment to the top
of files to enable frozen string literals. Frozen string literals may be
default in future Ruby. The comment will be added below a shebang and
encoding comment. The frozen string literal comment is only valid in Ruby 2.3+.
Note that the cop will accept files where the comment exists but is set
to false
instead of true
.
To require a blank line after this comment, please see
Layout/EmptyLineAfterMagicComment
cop.
Safety:
This cop's autocorrection is unsafe since any strings mutations will
change from being accepted to raising FrozenError
, as all strings
will become frozen by default, and will need to be manually refactored.
Example: EnforcedStyle: always (default)
# 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
# good
# frozen_string_literal: false
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
Example: EnforcedStyle: always_true
# The `always_true` style enforces that the frozen string literal
# comment is set to `true`. This is a stricter option than `always`
# and forces projects to use frozen string literals.
# bad
# frozen_string_literal: false
module Baz
# ...
end
# bad
module Baz
# ...
end
# good
# frozen_string_literal: true
module Bar
# ...
end
Missing top-level documentation comment for class User
. Open
class User < ActiveRecord::Base
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Checks for missing top-level documentation of classes and modules. Classes with no body are exempt from the check and so are namespace modules - modules that have nothing in their bodies except classes, other modules, constant definitions or constant visibility declarations.
The documentation requirement is annulled if the class or module has
a #:nodoc:
comment next to it. Likewise, #:nodoc: all
does the
same for all its children.
Example:
# bad
class Person
# ...
end
module Math
end
# good
# Description/Explanation of Person class
class Person
# ...
end
# allowed
# Class without body
class Person
end
# Namespace - A namespace can be a class or a module
# Containing a class
module Namespace
# Description/Explanation of Person class
class Person
# ...
end
end
# Containing constant visibility declaration
module Namespace
class Private
end
private_constant :Private
end
# Containing constant definition
module Namespace
Public = Class.new
end
# Macro calls
module Namespace
extend Foo
end
Example: AllowedConstants: ['ClassMethods']
# good
module A
module ClassMethods
# ...
end
end
Use the new Ruby 1.9 hash syntax. Open
devise :omniauthable, :rememberable, :trackable, :omniauth_providers => [:google_oauth2]
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Checks hash literal syntax.
It can enforce either the use of the class hash rocket syntax or the use of the newer Ruby 1.9 syntax (when applicable).
A separate offense is registered for each problematic pair.
The supported styles are:
- ruby19 - forces use of the 1.9 syntax (e.g.
{a: 1}
) when hashes have all symbols for keys - hash_rockets - forces use of hash rockets for all hashes
- nomixedkeys - simply checks for hashes with mixed syntaxes
- ruby19nomixed_keys - forces use of ruby 1.9 syntax and forbids mixed syntax hashes
This cop has EnforcedShorthandSyntax
option.
It can enforce either the use of the explicit hash value syntax or
the use of Ruby 3.1's hash value shorthand syntax.
The supported styles are:
- always - forces use of the 3.1 syntax (e.g. {foo:})
- never - forces use of explicit hash literal value
- either - accepts both shorthand and explicit use of hash literal value
- consistent - forces use of the 3.1 syntax only if all values can be omitted in the hash
Example: EnforcedStyle: ruby19 (default)
# bad
{:a => 2}
{b: 1, :c => 2}
# good
{a: 2, b: 1}
{:c => 2, 'd' => 2} # acceptable since 'd' isn't a symbol
{d: 1, 'e' => 2} # technically not forbidden
Example: EnforcedStyle: hash_rockets
# bad
{a: 1, b: 2}
{c: 1, 'd' => 5}
# good
{:a => 1, :b => 2}
Example: EnforcedStyle: nomixedkeys
# bad
{:a => 1, b: 2}
{c: 1, 'd' => 2}
# good
{:a => 1, :b => 2}
{c: 1, d: 2}
Example: EnforcedStyle: ruby19nomixed_keys
# bad
{:a => 1, :b => 2}
{c: 2, 'd' => 3} # should just use hash rockets
# good
{a: 1, b: 2}
{:c => 3, 'd' => 4}
Example: EnforcedShorthandSyntax: always (default)
# bad
{foo: foo, bar: bar}
# good
{foo:, bar:}
Example: EnforcedShorthandSyntax: never
# bad
{foo:, bar:}
# good
{foo: foo, bar: bar}
Example: EnforcedShorthandSyntax: either
# good
{foo: foo, bar: bar}
# good
{foo: foo, bar:}
# good
{foo:, bar:}
Example: EnforcedShorthandSyntax: consistent
# bad - `foo` and `bar` values can be omitted
{foo: foo, bar: bar}
# bad - `bar` value can be omitted
{foo:, bar: bar}
# bad - mixed syntaxes
{foo:, bar: baz}
# good
{foo:, bar:}
# good - can't omit `baz`
{foo: foo, bar: baz}
Extra empty line detected at method body end. Open
end
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Checks if empty lines exist around the bodies of methods.
Example:
# good
def foo
# ...
end
# bad
def bar
# ...
end
Trailing whitespace detected. Open
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Looks for trailing whitespace in the source code.
Example:
# The line in this example contains spaces after the 0.
# bad
x = 0
# The line in this example ends directly after the 0.
# good
x = 0
Example: AllowInHeredoc: false (default)
# The line in this example contains spaces after the 0.
# bad
code = <<~RUBY
x = 0
RUBY
# ok
code = <<~RUBY
x = 0 #{}
RUBY
# good
trailing_whitespace = ' '
code = <<~RUBY
x = 0#{trailing_whitespace}
RUBY
Example: AllowInHeredoc: true
# The line in this example contains spaces after the 0.
# good
code = <<~RUBY
x = 0
RUBY