This cop checks if the length a class exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

This cop checks that the ABC size of methods is not higher than the configured maximum. The ABC size is based on assignments, branches (method calls), and conditions. See http://c2.com/cgi/wiki?AbcMetric

This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

This cop checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.

An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn't add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one.

This cop tries to produce a complexity score that's a measure of the complexity the reader experiences when looking at a method. For that reason it considers when nodes as something that doesn't add as much complexity as an if or a &&. Except if it's one of those special case/when constructs where there's no expression after case. Then the cop treats it as an if/elsif/elsif... and lets all the when nodes count. In contrast to the CyclomaticComplexity cop, this cop considers else nodes as adding complexity.

Example:

def my_method                   # 1
  if cond                       # 1
    case var                    # 2 (0.8 + 4 * 0.2, rounded)
    when 1 then func_one
    when 2 then func_two
    when 3 then func_three
    when 4..10 then func_other
    end
  else                          # 1
    do_something until a && b   # 2
  end                           # ===
end                             # 7 complexity points

This cop checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.

An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn't add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one.

This cop checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.

An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn't add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one.

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

A method with Too Many Statements is any method that has a large number of lines.

Too Many Statements warns about any method that has more than 5 statements. Reek's smell detector for Too Many Statements counts +1 for every simple statement in a method and +1 for every statement within a control structure (if, else, case, when, for, while, until, begin, rescue) but it doesn't count the control structure itself.

So the following method would score +6 in Reek's statement-counting algorithm:

def parse(arg, argv, &error)
  if !(val = arg) and (argv.empty? or /\A-/ =~ (val = argv[0]))
    return nil, block, nil                                         # +1
  end
  opt = (val = parse_arg(val, &error))[1]                          # +2
  val = conv_arg(*val)                                             # +3
  if opt and !arg
    argv.shift                                                     # +4
  else
    val[0] = nil                                                   # +5
  end
  val                                                              # +6
end

(You might argue that the two assigments within the first @if@ should count as statements, and that perhaps the nested assignment should count as +2.)

A method with Too Many Statements is any method that has a large number of lines.

Too Many Statements warns about any method that has more than 5 statements. Reek's smell detector for Too Many Statements counts +1 for every simple statement in a method and +1 for every statement within a control structure (if, else, case, when, for, while, until, begin, rescue) but it doesn't count the control structure itself.

So the following method would score +6 in Reek's statement-counting algorithm:

def parse(arg, argv, &error)
  if !(val = arg) and (argv.empty? or /\A-/ =~ (val = argv[0]))
    return nil, block, nil                                         # +1
  end
  opt = (val = parse_arg(val, &error))[1]                          # +2
  val = conv_arg(*val)                                             # +3
  if opt and !arg
    argv.shift                                                     # +4
  else
    val[0] = nil                                                   # +5
  end
  val                                                              # +6
end

(You might argue that the two assigments within the first @if@ should count as statements, and that perhaps the nested assignment should count as +2.)

Too Many Instance Variables is a special case of LargeClass.

Example

Given this configuration

TooManyInstanceVariables:
  max_instance_variables: 3

and this code:

class TooManyInstanceVariables
  def initialize
    @arg_1 = :dummy
    @arg_2 = :dummy
    @arg_3 = :dummy
    @arg_4 = :dummy
  end
end

Reek would emit the following warning:

test.rb -- 5 warnings:
  [1]:TooManyInstanceVariables has at least 4 instance variables (TooManyInstanceVariables)

A method with Too Many Statements is any method that has a large number of lines.

Too Many Statements warns about any method that has more than 5 statements. Reek's smell detector for Too Many Statements counts +1 for every simple statement in a method and +1 for every statement within a control structure (if, else, case, when, for, while, until, begin, rescue) but it doesn't count the control structure itself.

So the following method would score +6 in Reek's statement-counting algorithm:

def parse(arg, argv, &error)
  if !(val = arg) and (argv.empty? or /\A-/ =~ (val = argv[0]))
    return nil, block, nil                                         # +1
  end
  opt = (val = parse_arg(val, &error))[1]                          # +2
  val = conv_arg(*val)                                             # +3
  if opt and !arg
    argv.shift                                                     # +4
  else
    val[0] = nil                                                   # +5
  end
  val                                                              # +6
end

(You might argue that the two assigments within the first @if@ should count as statements, and that perhaps the nested assignment should count as +2.)

Repeated Conditional is a special case of Simulated Polymorphism. Basically it means you are checking the same value throughout a single class and take decisions based on this.

Example

Given

class RepeatedConditionals
  attr_accessor :switch

  def repeat_1
    puts "Repeat 1!" if switch
  end

  def repeat_2
    puts "Repeat 2!" if switch
  end

  def repeat_3
    puts "Repeat 3!" if switch
  end
end

Reek would emit the following warning:

test.rb -- 4 warnings:
  [5, 9, 13]:RepeatedConditionals tests switch at least 3 times (RepeatedConditional)

If you get this warning then you are probably not using the right abstraction or even more probable, missing an additional abstraction.

Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.

Reek implements a check for Duplicate Method Call.

Example

Here's a very much simplified and contrived example. The following method will report a warning:

def double_thing()
  @other.thing + @other.thing
end

One quick approach to silence Reek would be to refactor the code thus:

def double_thing()
  thing = @other.thing
  thing + thing
end

A slightly different approach would be to replace all calls of double_thing by calls to @other.double_thing:

class Other
  def double_thing()
    thing + thing
  end
end

The approach you take will depend on balancing other factors in your code.

Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.

Reek implements a check for Duplicate Method Call.

Example

Here's a very much simplified and contrived example. The following method will report a warning:

def double_thing()
  @other.thing + @other.thing
end

One quick approach to silence Reek would be to refactor the code thus:

def double_thing()
  thing = @other.thing
  thing + thing
end

A slightly different approach would be to replace all calls of double_thing by calls to @other.double_thing:

class Other
  def double_thing()
    thing + thing
  end
end

The approach you take will depend on balancing other factors in your code.

Classes should not assume that instance variables are set or present outside of the current class definition.

Good:

class Foo
  def initialize
    @bar = :foo
  end

  def foo?
    @bar == :foo
  end
end

Good as well:

class Foo
  def foo?
    bar == :foo
  end

  def bar
    @bar ||= :foo
  end
end

Bad:

class Foo
  def go_foo!
    @bar = :foo
  end

  def foo?
    @bar == :foo
  end
end

Example

Running Reek on:

class Dummy
  def test
    @ivar
  end
end

would report:

[1]:InstanceVariableAssumption: Dummy assumes too much for instance variable @ivar

Note that this example would trigger this smell warning as well:

class Parent
  def initialize(omg)
    @omg = omg
  end
end

class Child < Parent
  def foo
    @omg
  end
end

The way to address the smell warning is that you should create an attr_reader to use @omg in the subclass and not access @omg directly like this:

class Parent
  attr_reader :omg

  def initialize(omg)
    @omg = omg
  end
end

class Child < Parent
  def foo
    omg
  end
end

Directly accessing instance variables is considered a smell because it breaks encapsulation and makes it harder to reason about code.

If you don't want to expose those methods as public API just make them private like this:

class Parent
  def initialize(omg)
    @omg = omg
  end

  private
  attr_reader :omg
end

class Child < Parent
  def foo
    omg
  end
end

Current Support in Reek

An instance variable must:

• be set in the constructor
• or be accessed through a method with lazy initialization / memoization.

If not, Instance Variable Assumption will be reported.

Class variables form part of the global runtime state, and as such make it easy for one part of the system to accidentally or inadvertently depend on another part of the system. So the system becomes more prone to problems where changing something over here breaks something over there. In particular, class variables can make it hard to set up tests (because the context of the test includes all global state).

For a detailed explanation, check out this article

Example

Given

class Dummy
  @@class_variable = :whatever
end

Reek would emit the following warning:

reek test.rb

test.rb -- 1 warning:
  [2]:Dummy declares the class variable @@class_variable (ClassVariable)

Getting rid of the smell

You can use class-instance variable to mitigate the problem (as also suggested in the linked article above):

class Dummy
  @class_variable = :whatever
end

Classes should not assume that instance variables are set or present outside of the current class definition.

Good:

class Foo
  def initialize
    @bar = :foo
  end

  def foo?
    @bar == :foo
  end
end

Good as well:

class Foo
  def foo?
    bar == :foo
  end

  def bar
    @bar ||= :foo
  end
end

Bad:

class Foo
  def go_foo!
    @bar = :foo
  end

  def foo?
    @bar == :foo
  end
end

Example

Running Reek on:

class Dummy
  def test
    @ivar
  end
end

would report:

[1]:InstanceVariableAssumption: Dummy assumes too much for instance variable @ivar

Note that this example would trigger this smell warning as well:

class Parent
  def initialize(omg)
    @omg = omg
  end
end

class Child < Parent
  def foo
    @omg
  end
end

The way to address the smell warning is that you should create an attr_reader to use @omg in the subclass and not access @omg directly like this:

class Parent
  attr_reader :omg

  def initialize(omg)
    @omg = omg
  end
end

class Child < Parent
  def foo
    omg
  end
end

Directly accessing instance variables is considered a smell because it breaks encapsulation and makes it harder to reason about code.

If you don't want to expose those methods as public API just make them private like this:

class Parent
  def initialize(omg)
    @omg = omg
  end

  private
  attr_reader :omg
end

class Child < Parent
  def foo
    omg
  end
end

Current Support in Reek

An instance variable must:

• be set in the constructor
• or be accessed through a method with lazy initialization / memoization.

If not, Instance Variable Assumption will be reported.

Classes should not assume that instance variables are set or present outside of the current class definition.

Good:

class Foo
  def initialize
    @bar = :foo
  end

  def foo?
    @bar == :foo
  end
end

Good as well:

class Foo
  def foo?
    bar == :foo
  end

  def bar
    @bar ||= :foo
  end
end

Bad:

class Foo
  def go_foo!
    @bar = :foo
  end

  def foo?
    @bar == :foo
  end
end

Example

Running Reek on:

class Dummy
  def test
    @ivar
  end
end

would report:

[1]:InstanceVariableAssumption: Dummy assumes too much for instance variable @ivar

Note that this example would trigger this smell warning as well:

class Parent
  def initialize(omg)
    @omg = omg
  end
end

class Child < Parent
  def foo
    @omg
  end
end

The way to address the smell warning is that you should create an attr_reader to use @omg in the subclass and not access @omg directly like this:

class Parent
  attr_reader :omg

  def initialize(omg)
    @omg = omg
  end
end

class Child < Parent
  def foo
    omg
  end
end

Directly accessing instance variables is considered a smell because it breaks encapsulation and makes it harder to reason about code.

If you don't want to expose those methods as public API just make them private like this:

class Parent
  def initialize(omg)
    @omg = omg
  end

  private
  attr_reader :omg
end

class Child < Parent
  def foo
    omg
  end
end

Current Support in Reek

An instance variable must:

• be set in the constructor
• or be accessed through a method with lazy initialization / memoization.

If not, Instance Variable Assumption will be reported.

Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.

Reek implements a check for Duplicate Method Call.

Example

Here's a very much simplified and contrived example. The following method will report a warning:

def double_thing()
  @other.thing + @other.thing
end

One quick approach to silence Reek would be to refactor the code thus:

def double_thing()
  thing = @other.thing
  thing + thing
end

A slightly different approach would be to replace all calls of double_thing by calls to @other.double_thing:

class Other
  def double_thing()
    thing + thing
  end
end

The approach you take will depend on balancing other factors in your code.

Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.

Reek implements a check for Duplicate Method Call.

Example

Here's a very much simplified and contrived example. The following method will report a warning:

def double_thing()
  @other.thing + @other.thing
end

One quick approach to silence Reek would be to refactor the code thus:

def double_thing()
  thing = @other.thing
  thing + thing
end

A slightly different approach would be to replace all calls of double_thing by calls to @other.double_thing:

class Other
  def double_thing()
    thing + thing
  end
end

The approach you take will depend on balancing other factors in your code.

Classes should not assume that instance variables are set or present outside of the current class definition.

Good:

class Foo
  def initialize
    @bar = :foo
  end

  def foo?
    @bar == :foo
  end
end

Good as well:

class Foo
  def foo?
    bar == :foo
  end

  def bar
    @bar ||= :foo
  end
end

Bad:

class Foo
  def go_foo!
    @bar = :foo
  end

  def foo?
    @bar == :foo
  end
end

Example

Running Reek on:

class Dummy
  def test
    @ivar
  end
end

would report:

[1]:InstanceVariableAssumption: Dummy assumes too much for instance variable @ivar

Note that this example would trigger this smell warning as well:

class Parent
  def initialize(omg)
    @omg = omg
  end
end

class Child < Parent
  def foo
    @omg
  end
end

The way to address the smell warning is that you should create an attr_reader to use @omg in the subclass and not access @omg directly like this:

class Parent
  attr_reader :omg

  def initialize(omg)
    @omg = omg
  end
end

class Child < Parent
  def foo
    omg
  end
end

Directly accessing instance variables is considered a smell because it breaks encapsulation and makes it harder to reason about code.

If you don't want to expose those methods as public API just make them private like this:

class Parent
  def initialize(omg)
    @omg = omg
  end

  private
  attr_reader :omg
end

class Child < Parent
  def foo
    omg
  end
end

Current Support in Reek

An instance variable must:

• be set in the constructor
• or be accessed through a method with lazy initialization / memoization.

If not, Instance Variable Assumption will be reported.

This cop checks whether the end keywords are aligned properly.

Three modes are supported through the EnforcedStyleAlignWith configuration parameter:

If it's set to keyword (which is the default), the end shall be aligned with the start of the keyword (if, class, etc.).

If it's set to variable the end shall be aligned with the left-hand-side of the variable assignment, if there is one.

If it's set to start_of_line, the end shall be aligned with the start of the line where the matching keyword appears.

Example: EnforcedStyleAlignWith: keyword (default)

# bad

variable = if true
    end

# good

variable = if true
           end

Example: EnforcedStyleAlignWith: variable

# bad

variable = if true
    end

# good

variable = if true
end

Example: EnforcedStyleAlignWith: startofline

# bad

variable = if true
    end

# good

puts(if true
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

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

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"

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"

Access modifiers should be surrounded by blank lines.

Example:

# bad
class Foo
  def bar; end
  private
  def baz; end
end

# good
class Foo
  def bar; end

  private

  def baz; end
end

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

Example: EnforcedStyle: empty_lines

# good

foo do |bar|

  # ...

end

Example: EnforcedStyle: noemptylines (default)

# good

foo do |bar|
  # ...
end

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

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"

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"

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

This cop checks for uses of and and or, and suggests using && and || instead. It can be configured to check only in conditions, or in all contexts.

Example: EnforcedStyle: always (default)

# bad
foo.save and return

# bad
if foo and bar
end

# good
foo.save && return

# good
if foo && bar
end

Example: EnforcedStyle: conditionals

# bad
if foo and bar
end

# good
foo.save && return

# good
foo.save and return

# good
if foo && bar
end

This cop checks for uses of and and or, and suggests using && and || instead. It can be configured to check only in conditions, or in all contexts.

Example: EnforcedStyle: always (default)

# bad
foo.save and return

# bad
if foo and bar
end

# good
foo.save && return

# good
if foo && bar
end

Example: EnforcedStyle: conditionals

# bad
if foo and bar
end

# good
foo.save && return

# good
foo.save and return

# good
if foo && bar
end

Checks for uses of if with a negated condition. Only ifs without else are considered. There are three different styles:

- both
- prefix
- postfix

Example: EnforcedStyle: both (default)

# enforces `unless` for `prefix` and `postfix` conditionals

# bad

if !foo
  bar
end

# good

unless foo
  bar
end

# bad

bar if !foo

# good

bar unless foo

Example: EnforcedStyle: prefix

# enforces `unless` for just `prefix` conditionals

# bad

if !foo
  bar
end

# good

unless foo
  bar
end

# good

bar if !foo

Example: EnforcedStyle: postfix

# enforces `unless` for just `postfix` conditionals

# bad

bar if !foo

# good

bar unless foo

# good

if !foo
  bar
end

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

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"

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"

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"

This cops checks for indentation that doesn't use the specified number of spaces.

See also the IndentationConsistency cop which is the companion to this one.

Example:

# bad
class A
 def test
  puts 'hello'
 end
end

# good
class A
  def test
    puts 'hello'
  end
end

Example: IgnoredPatterns: ['^\s*module']

# bad
module A
class B
  def test
  puts 'hello'
  end
end
end

# good
module A
class B
  def test
    puts 'hello'
  end
end
end

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

This cops checks for indentation that doesn't use the specified number of spaces.

See also the IndentationConsistency cop which is the companion to this one.

Example:

# bad
class A
 def test
  puts 'hello'
 end
end

# good
class A
  def test
    puts 'hello'
  end
end

Example: IgnoredPatterns: ['^\s*module']

# bad
module A
class B
  def test
  puts 'hello'
  end
end
end

# good
module A
class B
  def test
    puts 'hello'
  end
end
end

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

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"

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"

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"

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

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"

This cops checks for indentation that doesn't use the specified number of spaces.

See also the IndentationConsistency cop which is the companion to this one.

Example:

# bad
class A
 def test
  puts 'hello'
 end
end

# good
class A
  def test
    puts 'hello'
  end
end

Example: IgnoredPatterns: ['^\s*module']

# bad
module A
class B
  def test
  puts 'hello'
  end
end
end

# good
module A
class B
  def test
    puts 'hello'
  end
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

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for uses of and and or, and suggests using && and || instead. It can be configured to check only in conditions, or in all contexts.

Example: EnforcedStyle: always (default)

# bad
foo.save and return

# bad
if foo and bar
end

# good
foo.save && return

# good
if foo && bar
end

Example: EnforcedStyle: conditionals

# bad
if foo and bar
end

# good
foo.save && return

# good
foo.save and return

# good
if foo && bar
end

This cop checks for uses of and and or, and suggests using && and || instead. It can be configured to check only in conditions, or in all contexts.

Example: EnforcedStyle: always (default)

# bad
foo.save and return

# bad
if foo and bar
end

# good
foo.save && return

# good
if foo && bar
end

Example: EnforcedStyle: conditionals

# bad
if foo and bar
end

# good
foo.save && return

# good
foo.save and return

# good
if foo && bar
end

This cop checks for the use of a method, the result of which would be a literal, like an empty array, hash or string.

Example:

# bad
a = Array.new
h = Hash.new
s = String.new

# good
a = []
h = {}
s = ''

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"

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for uses of class variables. Offenses are signaled only on assignment to class variables to reduce the number of offenses that would be reported.

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

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"

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"

This cops checks for indentation that doesn't use the specified number of spaces.

See also the IndentationConsistency cop which is the companion to this one.

Example:

# bad
class A
 def test
  puts 'hello'
 end
end

# good
class A
  def test
    puts 'hello'
  end
end

Example: IgnoredPatterns: ['^\s*module']

# bad
module A
class B
  def test
  puts 'hello'
  end
end
end

# good
module A
class B
  def test
    puts 'hello'
  end
end
end

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cops checks the indentation of comments.

Example:

# bad
  # comment here
def method_name
end

  # comment here
a = 'hello'

# yet another comment
  if true
    true
  end

# good
# comment here
def method_name
end

# comment here
a = 'hello'

# yet another comment
if true
  true
end

This cops checks for indentation that doesn't use the specified number of spaces.

See also the IndentationConsistency cop which is the companion to this one.

Example:

# bad
class A
 def test
  puts 'hello'
 end
end

# good
class A
  def test
    puts 'hello'
  end
end

Example: IgnoredPatterns: ['^\s*module']

# bad
module A
class B
  def test
  puts 'hello'
  end
end
end

# good
module A
class B
  def test
    puts 'hello'
  end
end
end

This cops checks for inconsistent indentation.

Example:

class A
  def test
    puts 'hello'
     puts 'world'
  end
end

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

This cop checks for redundant parentheses.

Example:

# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

Modifiers should be indented as deep as method definitions, or as deep as the class/module keyword, depending on configuration.

Example: EnforcedStyle: indent (default)

# bad
class Plumbus
private
  def smooth; end
end

# good
class Plumbus
  private
  def smooth; end
end

Example: EnforcedStyle: outdent

# bad
class Plumbus
  private
  def smooth; end
end

# good
class Plumbus
private
  def smooth; end
end

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks whether comments have a leading space after the # denoting the start of the comment. The leading space is not required for some RDoc special syntax, like #++, #--, #:nodoc, =begin- and =end comments, "shebang" directives, or rackup options.

Example:

# bad
#Some comment

# good
# Some comment

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

Checks for spaces inside ordinary round parentheses.

Example:

# bad
f( 3)
g = (a + 3 )

# good
f(3)
g = (a + 3)

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

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"

This cop checks for the presence of superfluous parentheses around the condition of if/unless/while/until.

Example:

# bad
x += 1 while (x < 10)
foo unless (bar || baz)

if (x > 10)
elsif (x < 3)
end

# good
x += 1 while x < 10
foo unless bar || baz

if x > 10
elsif x < 3
end

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"