When defining the ==
operator, name its argument other
. Open
def ==(profile)
- Read upRead up
- Exclude checks
This cop makes sure that certain binary operator methods have their
sole parameter named other
.
Example:
# bad
def +(amount); end
# good
def +(other); end
Use alias
instead of alias_method
in a class body. Open
alias_method :eql?, :==
- Read upRead up
- Exclude checks
This cop enforces the use of either #alias
or #alias_method
depending on configuration.
It also flags uses of alias :symbol
rather than alias bareword
.
Example: EnforcedStyle: prefer_alias (default)
# bad
alias_method :bar, :foo
alias :bar :foo
# good
alias bar foo
Example: EnforcedStyle: preferaliasmethod
# bad
alias :bar :foo
alias bar foo
# good
alias_method :bar, :foo
Do not use space inside array brackets. Open
[ :name, :image, :email ].each do |_method|
- Read upRead up
- Exclude checks
Checks that brackets used for array literals have or don't have surrounding space depending on configuration.
Example: EnforcedStyle: space
# The `space` style enforces that array literals have
# surrounding space.
# bad
array = [a, b, c, d]
# good
array = [ a, b, c, d ]
Example: EnforcedStyle: no_space (default)
# The `no_space` style enforces that array literals have
# no surrounding space.
# bad
array = [ a, b, c, d ]
# good
array = [a, b, c, d]
Example: EnforcedStyle: compact
# The `compact` style normally requires a space inside
# array brackets, with the exception that successive left
# or right brackets are collapsed together in nested arrays.
# bad
array = [ a, [ b, c ] ]
array = [
[ a ],
[ b, c ]
]
# good
array = [ a, [ b, c ]]
array = [[ a ],
[ b, c ]]
Example: EnforcedStyleForEmptyBrackets: no_space (default)
# The `no_space` EnforcedStyleForEmptyBrackets style enforces that
# empty array brackets do not contain spaces.
# bad
foo = [ ]
bar = [ ]
# good
foo = []
bar = []
Example: EnforcedStyleForEmptyBrackets: space
# The `space` EnforcedStyleForEmptyBrackets style enforces that
# empty array brackets contain exactly one space.
# bad
foo = []
bar = [ ]
# good
foo = [ ]
bar = [ ]
Line is too long. [86/80] Open
current_providers = authentications.map { |auth| provider_by_name(auth.provider) }
- Exclude checks
Missing top-level class documentation comment. Open
class Provider
- Read upRead up
- Exclude checks
This cop 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, or constant definitions.
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
# good
# Description/Explanation of Person class
class Person
# ...
end
Missing magic comment # frozen_string_literal: true
. Open
class Authentication < ApplicationRecord
- Read upRead up
- Exclude checks
This cop is designed to help upgrade to after 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
after 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: 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
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
Avoid comma after the last item of an array. Open
Provider.new(:google_oauth2, :google),
- Read upRead up
- Exclude checks
This cop checks for trailing comma in array 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
]
Missing top-level class documentation comment. Open
class Authentication < ApplicationRecord
- Read upRead up
- Exclude checks
This cop 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, or constant definitions.
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
# good
# Description/Explanation of Person class
class Person
# ...
end
Avoid comparing a variable with multiple items in a conditional, use Array#include?
instead. Open
provider.name == name_or_aka || provider.aka == name_or_aka
- Read upRead up
- Exclude checks
This cop checks against comparing a variable with multiple items, where
Array#include?
could be used instead to avoid code repetition.
Example:
# bad
a = 'a'
foo if a == 'a' || a == 'b' || a == 'c'
# good
a = 'a'
foo if ['a', 'b', 'c'].include?(a)
Avoid using {...}
for multi-line blocks. Open
providers.find { |provider|
- Read upRead up
- Exclude checks
Check for uses of braces or do/end around single line or multi-line blocks.
Example: EnforcedStyle: linecountbased (default)
# bad - single line block
items.each do |item| item / 5 end
# good - single line block
items.each { |item| item / 5 }
# bad - multi-line block
things.map { |thing|
something = thing.some_method
process(something)
}
# good - multi-line block
things.map do |thing|
something = thing.some_method
process(something)
end
Example: EnforcedStyle: semantic
# Prefer `do...end` over `{...}` for procedural blocks.
# return value is used/assigned
# bad
foo = map do |x|
x
end
puts (map do |x|
x
end)
# return value is not used out of scope
# good
map do |x|
x
end
# Prefer `{...}` over `do...end` for functional blocks.
# return value is not used out of scope
# bad
each { |x|
x
}
# return value is used/assigned
# good
foo = map { |x|
x
}
map { |x|
x
}.inspect
# The AllowBracesOnProceduralOneLiners option is ignored unless the
# EnforcedStyle is set to `semantic`. If so:
# If the AllowBracesOnProceduralOneLiners option is unspecified, or
# set to `false` or any other falsey value, then semantic purity is
# maintained, so one-line procedural blocks must use do-end, not
# braces.
# bad
collection.each { |element| puts element }
# good
collection.each do |element| puts element end
# If the AllowBracesOnProceduralOneLiners option is set to `true`, or
# any other truthy value, then one-line procedural blocks may use
# either style. (There is no setting for requiring braces on them.)
# good
collection.each { |element| puts element }
# also good
collection.each do |element| puts element end
Example: EnforcedStyle: bracesforchaining
# bad
words.each do |word|
word.flip.flop
end.join("-")
# good
words.each { |word|
word.flip.flop
}.join("-")
Example: EnforcedStyle: always_braces
# bad
words.each do |word|
word.flip.flop
end
# good
words.each { |word|
word.flip.flop
}
Do not use space inside array brackets. Open
[ :name, :image, :email ].each do |_method|
- Read upRead up
- Exclude checks
Checks that brackets used for array literals have or don't have surrounding space depending on configuration.
Example: EnforcedStyle: space
# The `space` style enforces that array literals have
# surrounding space.
# bad
array = [a, b, c, d]
# good
array = [ a, b, c, d ]
Example: EnforcedStyle: no_space (default)
# The `no_space` style enforces that array literals have
# no surrounding space.
# bad
array = [ a, b, c, d ]
# good
array = [a, b, c, d]
Example: EnforcedStyle: compact
# The `compact` style normally requires a space inside
# array brackets, with the exception that successive left
# or right brackets are collapsed together in nested arrays.
# bad
array = [ a, [ b, c ] ]
array = [
[ a ],
[ b, c ]
]
# good
array = [ a, [ b, c ]]
array = [[ a ],
[ b, c ]]
Example: EnforcedStyleForEmptyBrackets: no_space (default)
# The `no_space` EnforcedStyleForEmptyBrackets style enforces that
# empty array brackets do not contain spaces.
# bad
foo = [ ]
bar = [ ]
# good
foo = []
bar = []
Example: EnforcedStyleForEmptyBrackets: space
# The `space` EnforcedStyleForEmptyBrackets style enforces that
# empty array brackets contain exactly one space.
# bad
foo = []
bar = [ ]
# good
foo = [ ]
bar = [ ]
Use %i
or %I
for an array of symbols. Open
[ :name, :image, :email ].each do |_method|
- Read upRead up
- Exclude checks
This cop can check for array literals made up of symbols that are not using the %i() syntax.
Alternatively, it checks for symbol arrays using the %i() syntax on projects which do not want to use that syntax.
Configuration option: MinSize
If set, arrays with fewer elements than this value will not trigger the
cop. For example, a MinSize of
3` will not enforce a style on an array
of 2 or fewer elements.
Example: EnforcedStyle: percent (default)
# good
%i[foo bar baz]
# bad
[:foo, :bar, :baz]
Example: EnforcedStyle: brackets
# good
[:foo, :bar, :baz]
# bad
%i[foo bar baz]
Do not use prefix _
for a variable that is used. Open
[ :name, :image, :email ].each do |_method|
- Read upRead up
- Exclude checks
This cop checks for underscore-prefixed variables that are actually used.
Since block keyword arguments cannot be arbitrarily named at call
sites, the AllowKeywordBlockArguments
will allow use of underscore-
prefixed block keyword arguments.
Example: AllowKeywordBlockArguments: false (default)
# bad
[1, 2, 3].each do |_num|
do_something(_num)
end
query(:sales) do |_id:, revenue:, cost:|
{_id: _id, profit: revenue - cost}
end
# good
[1, 2, 3].each do |num|
do_something(num)
end
[1, 2, 3].each do |_num|
do_something # not using `_num`
end
Example: AllowKeywordBlockArguments: true
# good
query(:sales) do |_id:, revenue:, cost:|
{_id: _id, profit: revenue - cost}
end
Use the double pipe equals operator ||=
instead. Open
@aka = @name unless @aka
- Read upRead up
- Exclude checks
This cop checks for potential usage of the ||=
operator.
Example:
# bad
name = name ? name : 'Bozhidar'
# bad
name = if name
name
else
'Bozhidar'
end
# bad
unless name
name = 'Bozhidar'
end
# bad
name = 'Bozhidar' unless name
# good - set name to 'Bozhidar', only if it's nil or false
name ||= 'Bozhidar'
Do not use parallel assignment. Open
@name, @aka = name, aka
- Read upRead up
- Exclude checks
Checks for simple usages of parallel assignment. This will only complain when the number of variables being assigned matched the number of assigning variables.
Example:
# bad
a, b, c = 1, 2, 3
a, b, c = [1, 2, 3]
# good
one, two = *foo
a, b = foo()
a, b = b, a
a = 1
b = 2
c = 3
Unused method argument - raw
. If it's necessary, use _
or _raw
as an argument name to indicate that it won't be used. You can also write as providers(*)
if you want the method to accept any arguments but don't care about them. Open
def self.providers(raw = false)
- Read upRead up
- Exclude checks
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