Freeze mutable objects assigned to constants. Open
STATUS_CHOICES = [ "Active", "Expired" ]
- Read upRead up
- Exclude checks
This cop checks whether some constant value isn't a mutable literal (e.g. array or hash).
Example:
# bad
CONST = [1, 2, 3]
# good
CONST = [1, 2, 3].freeze
Do not use space inside array brackets. Open
STATUS_CHOICES = [ "Active", "Expired" ]
- 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
# 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 ] ]
# good
array = [ a, [ b, c ]]
Missing top-level class documentation comment. Open
class Grant < 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
Missing magic comment # frozen_string_literal: true
. Open
class Grant < ApplicationRecord
- Read upRead up
- Exclude checks
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
Favor modifier if
usage when having a single-line body. Another good alternative is the usage of control flow &&
/||
. Open
if end_date < start_date
- Read upRead up
- Exclude checks
Checks for if and unless statements that would fit on one line
if written as a modifier if/unless. The maximum line length is
configured in the Metrics/LineLength
cop.
Example:
# bad
if condition
do_stuff(bar)
end
unless qux.empty?
Foo.do_something
end
# good
do_stuff(bar) if condition
Foo.do_something unless qux.empty?
Prefer single-quoted strings when you don't need string interpolation or special symbols. Open
errors.add :end_date, "must be after start date"
- Read upRead up
- Exclude checks
Checks if uses of quotes match the configured preference.
Example: EnforcedStyle: single_quotes (default)
# bad
"No special symbols"
"No string interpolation"
"Just text"
# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"
Example: EnforcedStyle: double_quotes
# bad
'Just some text'
'No special chars or interpolation'
# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"
Prefer single-quoted strings when you don't need string interpolation or special symbols. Open
scope :active, -> { where(status: "Active") }
- Read upRead up
- Exclude checks
Checks if uses of quotes match the configured preference.
Example: EnforcedStyle: single_quotes (default)
# bad
"No special symbols"
"No string interpolation"
"Just text"
# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"
Example: EnforcedStyle: double_quotes
# bad
'Just some text'
'No special chars or interpolation'
# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"
Prefer single-quoted strings when you don't need string interpolation or special symbols. Open
STATUS_CHOICES = [ "Active", "Expired" ]
- Read upRead up
- Exclude checks
Checks if uses of quotes match the configured preference.
Example: EnforcedStyle: single_quotes (default)
# bad
"No special symbols"
"No string interpolation"
"Just text"
# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"
Example: EnforcedStyle: double_quotes
# bad
'Just some text'
'No special chars or interpolation'
# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"
Prefer single-quoted strings when you don't need string interpolation or special symbols. Open
STATUS_CHOICES = [ "Active", "Expired" ]
- Read upRead up
- Exclude checks
Checks if uses of quotes match the configured preference.
Example: EnforcedStyle: single_quotes (default)
# bad
"No special symbols"
"No string interpolation"
"Just text"
# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"
Example: EnforcedStyle: double_quotes
# bad
'Just some text'
'No special chars or interpolation'
# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"
Do not use space inside array brackets. Open
STATUS_CHOICES = [ "Active", "Expired" ]
- 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
# 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 ] ]
# good
array = [ a, [ b, c ]]
Use a guard clause instead of wrapping the code inside a conditional expression. Open
if end_date < start_date
- Read upRead up
- Exclude checks
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
Use %w
or %W
for an array of words. Open
STATUS_CHOICES = [ "Active", "Expired" ]
- Read upRead up
- Exclude checks
This cop can check for array literals made up of word-like strings, that are not using the %w() syntax.
Alternatively, it can check for uses of the %w() syntax, in projects which do not want to include 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
%w[foo bar baz]
# bad
['foo', 'bar', 'baz']
Example: EnforcedStyle: brackets
# good
['foo', 'bar', 'baz']
# bad
%w[foo bar baz]