kirushik/critical_chain

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

You can set constructs you want to fold with CountAsOne. Available are: 'array', 'hash', 'heredoc', and 'method_call'. Each construct will be counted as one line regardless of its actual size.

NOTE: The ExcludedMethods and IgnoredMethods configuration is deprecated and only kept for backwards compatibility. Please use AllowedMethods and AllowedPatterns instead. By default, there are no methods to allowed.

Example: CountAsOne: ['array', 'heredoc', 'method_call']

def m
  array = [       # +1
    1,
    2
  ]

  hash = {        # +3
    key: 'value'
  }

  <<~HEREDOC      # +1
    Heredoc
    content.
  HEREDOC

  foo(            # +1
    1,
    2
  )
end               # 6 points

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 assignments 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 assignments 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.

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.

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 and https://en.wikipedia.org/wiki/ABC_Software_Metric.

Interpreting ABC size:

• <= 17 satisfactory
• 18..30 unsatisfactory
• > 30 dangerous

You can have repeated "attributes" calls count as a single "branch". For this purpose, attributes are any method with no argument; no attempt is meant to distinguish actual attr_reader from other methods.

Example: CountRepeatedAttributes: false (default is true)

# `model` and `current_user`, referenced 3 times each,
 # are each counted as only 1 branch each if
 # `CountRepeatedAttributes` is set to 'false'

 def search
   @posts = model.active.visible_by(current_user)
             .search(params[:q])
   @posts = model.some_process(@posts, current_user)
   @posts = model.another_process(@posts, current_user)

   render 'pages/search/page'
 end

This cop also takes into account AllowedMethods (defaults to []) And AllowedPatterns (defaults to [])

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

Checks for places where string concatenation can be replaced with string interpolation.

The cop can autocorrect simple cases but will skip autocorrecting more complex cases where the resulting code would be harder to read. In those cases, it might be useful to extract statements to local variables or methods which you can then interpolate in a string.

NOTE: When concatenation between two strings is broken over multiple lines, this cop does not register an offense; instead, Style/LineEndConcatenation will pick up the offense if enabled.

Two modes are supported: 1. aggressive style checks and corrects all occurrences of + where either the left or right side of + is a string literal. 2. conservative style on the other hand, checks and corrects only if left side (receiver of + method call) is a string literal. This is useful when the receiver is some expression that returns string like Pathname instead of a string literal.

Safety:

This cop is unsafe in aggressive mode, as it cannot be guaranteed that the receiver is actually a string, which can result in a false positive.

Example: Mode: aggressive (default)

# bad
email_with_name = user.name + ' <' + user.email + '>'
Pathname.new('/') + 'test'

# good
email_with_name = "#{user.name} <#{user.email}>"
email_with_name = format('%s <%s>', user.name, user.email)
"#{Pathname.new('/')}test"

# accepted, line-end concatenation
name = 'First' +
  'Last'

Example: Mode: conservative

# bad
'Hello' + user.name

# good
"Hello #{user.name}"
user.name + '!!'
Pathname.new('/') + 'test'

Checks the indentation of the first key in a hash literal where the opening brace and the first key are on separate lines. The other keys' indentations are handled by the HashAlignment cop.

By default, Hash literals that are arguments in a method call with parentheses, and where the opening curly brace of the hash is on the same line as the opening parenthesis of the method call, shall have their first key indented one step (two spaces) more than the position inside the opening parenthesis.

Other hash literals shall have their first key indented one step more than the start of the line where the opening curly brace is.

This default style is called 'specialinsideparentheses'. Alternative styles are 'consistent' and 'align_braces'. Here are examples:

Example: EnforcedStyle: specialinsideparentheses (default)

# The `special_inside_parentheses` style enforces that the first key
# in a hash literal where the opening brace and the first key are on
# separate lines is indented one step (two spaces) more than the
# position inside the opening parentheses.

# bad
hash = {
  key: :value
}
and_in_a_method_call({
  no: :difference
                     })
takes_multi_pairs_hash(x: {
  a: 1,
  b: 2
},
                       y: {
                         c: 1,
                         d: 2
                       })

# good
special_inside_parentheses
hash = {
  key: :value
}
but_in_a_method_call({
                       its_like: :this
                     })
takes_multi_pairs_hash(x: {
                         a: 1,
                         b: 2
                       },
                       y: {
                         c: 1,
                         d: 2
                       })

Example: EnforcedStyle: consistent

# The `consistent` style enforces that the first key in a hash
# literal where the opening brace and the first key are on
# separate lines is indented the same as a hash literal which is not
# defined inside a method call.

# bad
hash = {
  key: :value
}
but_in_a_method_call({
                       its_like: :this
                      })

# good
hash = {
  key: :value
}
and_in_a_method_call({
  no: :difference
})

Example: EnforcedStyle: align_braces

# The `align_brackets` style enforces that the opening and closing
# braces are indented to the same position.

# bad
and_now_for_something = {
                          completely: :different
}
takes_multi_pairs_hash(x: {
  a: 1,
  b: 2
},
                        y: {
                             c: 1,
                             d: 2
                           })

# good
and_now_for_something = {
                          completely: :different
                        }
takes_multi_pairs_hash(x: {
                            a: 1,
                            b: 2
                          },
                       y: {
                            c: 1,
                            d: 2
                          })

Checks for trailing comma in hash literals. The configuration options are:

• consistent_comma: Requires a comma after the last item of all non-empty, multiline hash literals.
• comma: Requires a comma after the last item in a hash, but only when each item is on its own line.
• no_comma: Does not require a comma after the last item in a hash

Example: EnforcedStyleForMultiline: consistent_comma

# bad
a = { foo: 1, bar: 2, }

# good
a = { foo: 1, bar: 2 }

# good
a = {
  foo: 1, bar: 2,
  qux: 3,
}

# good
a = {
  foo: 1, bar: 2, qux: 3,
}

# good
a = {
  foo: 1,
  bar: 2,
}

Example: EnforcedStyleForMultiline: comma

# bad
a = { foo: 1, bar: 2, }

# good
a = { foo: 1, bar: 2 }

# bad
a = {
  foo: 1, bar: 2,
  qux: 3,
}

# good
a = {
  foo: 1, bar: 2,
  qux: 3
}

# bad
a = {
  foo: 1, bar: 2, qux: 3,
}

# good
a = {
  foo: 1, bar: 2, qux: 3
}

# good
a = {
  foo: 1,
  bar: 2,
}

Example: EnforcedStyleForMultiline: no_comma (default)

# bad
a = { foo: 1, bar: 2, }

# good
a = {
  foo: 1,
  bar: 2
}

Checks for trailing comma in hash literals. The configuration options are:

• consistent_comma: Requires a comma after the last item of all non-empty, multiline hash literals.
• comma: Requires a comma after the last item in a hash, but only when each item is on its own line.
• no_comma: Does not require a comma after the last item in a hash

Example: EnforcedStyleForMultiline: consistent_comma

# bad
a = { foo: 1, bar: 2, }

# good
a = { foo: 1, bar: 2 }

# good
a = {
  foo: 1, bar: 2,
  qux: 3,
}

# good
a = {
  foo: 1, bar: 2, qux: 3,
}

# good
a = {
  foo: 1,
  bar: 2,
}

Example: EnforcedStyleForMultiline: comma

# bad
a = { foo: 1, bar: 2, }

# good
a = { foo: 1, bar: 2 }

# bad
a = {
  foo: 1, bar: 2,
  qux: 3,
}

# good
a = {
  foo: 1, bar: 2,
  qux: 3
}

# bad
a = {
  foo: 1, bar: 2, qux: 3,
}

# good
a = {
  foo: 1, bar: 2, qux: 3
}

# good
a = {
  foo: 1,
  bar: 2,
}

Example: EnforcedStyleForMultiline: no_comma (default)

# bad
a = { foo: 1, bar: 2, }

# good
a = {
  foo: 1,
  bar: 2
}

Check that the keys, separators, and values of a multi-line hash literal are aligned according to configuration. The configuration options are:

• key (left align keys, one space before hash rockets and values)
• separator (align hash rockets and colons, right align keys)
• table (left align keys, hash rockets, and values)

The treatment of hashes passed as the last argument to a method call can also be configured. The options are:

• always_inspect
• always_ignore
• ignore_implicit (without curly braces)

Alternatively you can specify multiple allowed styles. That's done by passing a list of styles to EnforcedStyles.

Example: EnforcedHashRocketStyle: key (default)

# bad
{
  :foo => bar,
   :ba => baz
}
{
  :foo => bar,
  :ba  => baz
}

# good
{
  :foo => bar,
  :ba => baz
}

Example: EnforcedHashRocketStyle: separator

# bad
{
  :foo => bar,
  :ba => baz
}
{
  :foo => bar,
  :ba  => baz
}

# good
{
  :foo => bar,
   :ba => baz
}

Example: EnforcedHashRocketStyle: table

# bad
{
  :foo => bar,
   :ba => baz
}

# good
{
  :foo => bar,
  :ba  => baz
}

Example: EnforcedColonStyle: key (default)

# bad
{
  foo: bar,
   ba: baz
}
{
  foo: bar,
  ba:  baz
}

# good
{
  foo: bar,
  ba: baz
}

Example: EnforcedColonStyle: separator

# bad
{
  foo: bar,
  ba: baz
}

# good
{
  foo: bar,
   ba: baz
}

Example: EnforcedColonStyle: table

# bad
{
  foo: bar,
  ba: baz
}

# good
{
  foo: bar,
  ba:  baz
}

Example: EnforcedLastArgumentHashStyle: always_inspect (default)

# Inspect both implicit and explicit hashes.

# bad
do_something(foo: 1,
  bar: 2)

# bad
do_something({foo: 1,
  bar: 2})

# good
do_something(foo: 1,
             bar: 2)

# good
do_something(
  foo: 1,
  bar: 2
)

# good
do_something({foo: 1,
              bar: 2})

# good
do_something({
  foo: 1,
  bar: 2
})

Example: EnforcedLastArgumentHashStyle: always_ignore

# Ignore both implicit and explicit hashes.

# good
do_something(foo: 1,
  bar: 2)

# good
do_something({foo: 1,
  bar: 2})

Example: EnforcedLastArgumentHashStyle: ignore_implicit

# Ignore only implicit hashes.

# bad
do_something({foo: 1,
  bar: 2})

# good
do_something(foo: 1,
  bar: 2)

Example: EnforcedLastArgumentHashStyle: ignore_explicit

# Ignore only explicit hashes.

# bad
do_something(foo: 1,
  bar: 2)

# good
do_something({foo: 1,
  bar: 2})

Check that the keys, separators, and values of a multi-line hash literal are aligned according to configuration. The configuration options are:

• key (left align keys, one space before hash rockets and values)
• separator (align hash rockets and colons, right align keys)
• table (left align keys, hash rockets, and values)

The treatment of hashes passed as the last argument to a method call can also be configured. The options are:

• always_inspect
• always_ignore
• ignore_implicit (without curly braces)

Alternatively you can specify multiple allowed styles. That's done by passing a list of styles to EnforcedStyles.

Example: EnforcedHashRocketStyle: key (default)

# bad
{
  :foo => bar,
   :ba => baz
}
{
  :foo => bar,
  :ba  => baz
}

# good
{
  :foo => bar,
  :ba => baz
}

Example: EnforcedHashRocketStyle: separator

# bad
{
  :foo => bar,
  :ba => baz
}
{
  :foo => bar,
  :ba  => baz
}

# good
{
  :foo => bar,
   :ba => baz
}

Example: EnforcedHashRocketStyle: table

# bad
{
  :foo => bar,
   :ba => baz
}

# good
{
  :foo => bar,
  :ba  => baz
}

Example: EnforcedColonStyle: key (default)

# bad
{
  foo: bar,
   ba: baz
}
{
  foo: bar,
  ba:  baz
}

# good
{
  foo: bar,
  ba: baz
}

Example: EnforcedColonStyle: separator

# bad
{
  foo: bar,
  ba: baz
}

# good
{
  foo: bar,
   ba: baz
}

Example: EnforcedColonStyle: table

# bad
{
  foo: bar,
  ba: baz
}

# good
{
  foo: bar,
  ba:  baz
}

Example: EnforcedLastArgumentHashStyle: always_inspect (default)

# Inspect both implicit and explicit hashes.

# bad
do_something(foo: 1,
  bar: 2)

# bad
do_something({foo: 1,
  bar: 2})

# good
do_something(foo: 1,
             bar: 2)

# good
do_something(
  foo: 1,
  bar: 2
)

# good
do_something({foo: 1,
              bar: 2})

# good
do_something({
  foo: 1,
  bar: 2
})

Example: EnforcedLastArgumentHashStyle: always_ignore

# Ignore both implicit and explicit hashes.

# good
do_something(foo: 1,
  bar: 2)

# good
do_something({foo: 1,
  bar: 2})

Example: EnforcedLastArgumentHashStyle: ignore_implicit

# Ignore only implicit hashes.

# bad
do_something({foo: 1,
  bar: 2})

# good
do_something(foo: 1,
  bar: 2)

Example: EnforcedLastArgumentHashStyle: ignore_explicit

# Ignore only explicit hashes.

# bad
do_something(foo: 1,
  bar: 2)

# good
do_something({foo: 1,
  bar: 2})

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

Checks the indentation of the first key in a hash literal where the opening brace and the first key are on separate lines. The other keys' indentations are handled by the HashAlignment cop.

By default, Hash literals that are arguments in a method call with parentheses, and where the opening curly brace of the hash is on the same line as the opening parenthesis of the method call, shall have their first key indented one step (two spaces) more than the position inside the opening parenthesis.

Other hash literals shall have their first key indented one step more than the start of the line where the opening curly brace is.

This default style is called 'specialinsideparentheses'. Alternative styles are 'consistent' and 'align_braces'. Here are examples:

Example: EnforcedStyle: specialinsideparentheses (default)

# The `special_inside_parentheses` style enforces that the first key
# in a hash literal where the opening brace and the first key are on
# separate lines is indented one step (two spaces) more than the
# position inside the opening parentheses.

# bad
hash = {
  key: :value
}
and_in_a_method_call({
  no: :difference
                     })
takes_multi_pairs_hash(x: {
  a: 1,
  b: 2
},
                       y: {
                         c: 1,
                         d: 2
                       })

# good
special_inside_parentheses
hash = {
  key: :value
}
but_in_a_method_call({
                       its_like: :this
                     })
takes_multi_pairs_hash(x: {
                         a: 1,
                         b: 2
                       },
                       y: {
                         c: 1,
                         d: 2
                       })

Example: EnforcedStyle: consistent

# The `consistent` style enforces that the first key in a hash
# literal where the opening brace and the first key are on
# separate lines is indented the same as a hash literal which is not
# defined inside a method call.

# bad
hash = {
  key: :value
}
but_in_a_method_call({
                       its_like: :this
                      })

# good
hash = {
  key: :value
}
and_in_a_method_call({
  no: :difference
})

Example: EnforcedStyle: align_braces

# The `align_brackets` style enforces that the opening and closing
# braces are indented to the same position.

# bad
and_now_for_something = {
                          completely: :different
}
takes_multi_pairs_hash(x: {
  a: 1,
  b: 2
},
                        y: {
                             c: 1,
                             d: 2
                           })

# good
and_now_for_something = {
                          completely: :different
                        }
takes_multi_pairs_hash(x: {
                            a: 1,
                            b: 2
                          },
                       y: {
                            c: 1,
                            d: 2
                          })

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"