Freeze mutable objects assigned to constants. Open
COLLECTIONS = [ :authentications, :comments, :events, :proposals, :votes ]
- Read upRead up
- Exclude checks
This cop checks whether some constant value isn't a mutable literal (e.g. array or hash).
Strict mode can be used to freeze all constants, rather than just literals. Strict mode is considered an experimental feature. It has not been updated with an exhaustive list of all methods that will produce frozen objects so there is a decent chance of getting some false positives. Luckily, there is no harm in freezing an already frozen object.
Example: EnforcedStyle: literals (default)
# bad
CONST = [1, 2, 3]
# good
CONST = [1, 2, 3].freeze
# good
CONST = <<~TESTING.freeze
This is a heredoc
TESTING
# good
CONST = Something.new
Example: EnforcedStyle: strict
# bad
CONST = Something.new
# bad
CONST = Struct.new do
def foo
puts 1
end
end
# good
CONST = Something.new.freeze
# good
CONST = Struct.new do
def foo
puts 1
end
end.freeze
Do not use space inside array brackets. Open
COLLECTIONS = [ :authentications, :comments, :events, :proposals, :votes ]
- 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 = [ ]
Avoid using {...}
for multi-line blocks. Open
@profiles_to_remove.map { |profile|
- 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
}
Avoid using {...}
for multi-line blocks. Open
profiles.sort { |p1, p2|
- 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
}
Missing magic comment # frozen_string_literal: true
. Open
class MergeUser
- 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
Do not use space inside array brackets. Open
COLLECTIONS = [ :authentications, :comments, :events, :proposals, :votes ]
- 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 max
instead of sort...last
. Open
profiles.sort { |p1, p2|
count_associations(p1) <=> count_associations(p2)
}.last
- Read upRead up
- Exclude checks
This cop is used to identify instances of sorting and then
taking only the first or last element. The same behavior can
be accomplished without a relatively expensive sort by using
Enumerable#min
instead of sorting and taking the first
element and Enumerable#max
instead of sorting and taking the
last element. Similarly, Enumerable#min_by
and
Enumerable#max_by
can replace Enumerable#sort_by
calls
after which only the first or last element is used.
Example:
# bad
[2, 1, 3].sort.first
[2, 1, 3].sort[0]
[2, 1, 3].sort.at(0)
[2, 1, 3].sort.slice(0)
# good
[2, 1, 3].min
# bad
[2, 1, 3].sort.last
[2, 1, 3].sort[-1]
[2, 1, 3].sort.at(-1)
[2, 1, 3].sort.slice(-1)
# good
[2, 1, 3].max
# bad
arr.sort_by(&:foo).first
arr.sort_by(&:foo)[0]
arr.sort_by(&:foo).at(0)
arr.sort_by(&:foo).slice(0)
# good
arr.min_by(&:foo)
# bad
arr.sort_by(&:foo).last
arr.sort_by(&:foo)[-1]
arr.sort_by(&:foo).at(-1)
arr.sort_by(&:foo).slice(-1)
# good
arr.max_by(&:foo)
Add empty line after guard clause. Open
return if user.photo?
- Read upRead up
- Exclude checks
This cop enforces empty line after guard clause
Example:
# bad
def foo
return if need_return?
bar
end
# good
def foo
return if need_return?
bar
end
# good
def foo
return if something?
return if something_different?
bar
end
# also good
def foo
if something?
do_something
return if need_return?
end
end
Missing top-level class documentation comment. Open
class MergeUser
- 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
Use %i
or %I
for an array of symbols. Open
COLLECTIONS = [ :authentications, :comments, :events, :proposals, :votes ]
- 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]