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 literals you want to fold with CountAsOne. Available are: 'array', 'hash', and 'heredoc'. Each literal 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']

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

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

  <<~HEREDOC      # +1
    Heredoc
    content.
  HEREDOC
end               # 5 points

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

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 [])

This cop checks for the use of Time methods without zone.

Built on top of Ruby on Rails style guide (https://github.com/rubocop-hq/rails-style-guide#time) and the article http://danilenko.org/2012/7/6/rails_timezones/

Two styles are supported for this cop. When EnforcedStyle is 'strict' then only use of Time.zone is allowed.

When EnforcedStyle is 'flexible' then it's also allowed to use Time.intimezone.

Example: EnforcedStyle: strict

# `strict` means that `Time` should be used with `zone`.

# bad
Time.now
Time.parse('2015-03-02 19:05:37')

# bad
Time.current
Time.at(timestamp).in_time_zone

# good
Time.zone.now
Time.zone.parse('2015-03-02 19:05:37')

Example: EnforcedStyle: flexible (default)

# `flexible` allows usage of `in_time_zone` instead of `zone`.

# bad
Time.now
Time.parse('2015-03-02 19:05:37')

# good
Time.zone.now
Time.zone.parse('2015-03-02 19:05:37')

# good
Time.current
Time.at(timestamp).in_time_zone

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

Checks for every useless assignment to local variable in every scope. The basic idea for this cop was from the warning of ruby -cw:

assigned but unused variable - foo

Currently this cop has advanced logic that detects unreferenced reassignments and properly handles varied cases such as branch, loop, rescue, ensure, etc.

Example:

# bad

def some_method
  some_var = 1
  do_something
end

Example:

# good

def some_method
  some_var = 1
  do_something(some_var)
end

Checks for rescuing StandardError. There are two supported styles implicit and explicit. This cop will not register an offense if any error other than StandardError is specified.

Example: EnforcedStyle: explicit (default)

# `explicit` will enforce using `rescue StandardError`
# instead of `rescue`.

# bad
begin
  foo
rescue
  bar
end

# good
begin
  foo
rescue StandardError
  bar
end

# good
begin
  foo
rescue OtherError
  bar
end

# good
begin
  foo
rescue StandardError, SecurityError
  bar
end

Example: EnforcedStyle: implicit

# `implicit` will enforce using `rescue` instead of
# `rescue StandardError`.

# bad
begin
  foo
rescue StandardError
  bar
end

# good
begin
  foo
rescue
  bar
end

# good
begin
  foo
rescue OtherError
  bar
end

# good
begin
  foo
rescue StandardError, SecurityError
  bar
end

This cop checks for the use of Time methods without zone.

Built on top of Ruby on Rails style guide (https://github.com/rubocop-hq/rails-style-guide#time) and the article http://danilenko.org/2012/7/6/rails_timezones/

Two styles are supported for this cop. When EnforcedStyle is 'strict' then only use of Time.zone is allowed.

When EnforcedStyle is 'flexible' then it's also allowed to use Time.intimezone.

Example: EnforcedStyle: strict

# `strict` means that `Time` should be used with `zone`.

# bad
Time.now
Time.parse('2015-03-02 19:05:37')

# bad
Time.current
Time.at(timestamp).in_time_zone

# good
Time.zone.now
Time.zone.parse('2015-03-02 19:05:37')

Example: EnforcedStyle: flexible (default)

# `flexible` allows usage of `in_time_zone` instead of `zone`.

# bad
Time.now
Time.parse('2015-03-02 19:05:37')

# good
Time.zone.now
Time.zone.parse('2015-03-02 19:05:37')

# good
Time.current
Time.at(timestamp).in_time_zone