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

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

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 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 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.

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

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

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

This cop checks if the length of a block exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable. The cop can be configured to ignore blocks passed to certain methods.

This cop checks if the length of a block exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable. The cop can be configured to ignore blocks passed to certain methods.

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

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

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.

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 block exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable. The cop can be configured to ignore blocks passed to certain methods.

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

This cop checks if the length of a block exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable. The cop can be configured to ignore blocks passed to certain methods.

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

This cop checks whether the multiline do end blocks have a newline after the start of the block. Additionally, it checks whether the block arguments, if any, are on the same line as the start of the block.

Example:

# bad
blah do |i| foo(i)
  bar(i)
end

# bad
blah do
  |i| foo(i)
  bar(i)
end

# good
blah do |i|
  foo(i)
  bar(i)
end

# bad
blah { |i| foo(i)
  bar(i)
}

# good
blah { |i|
  foo(i)
  bar(i)
}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

This cop checks whether the multiline do end blocks have a newline after the start of the block. Additionally, it checks whether the block arguments, if any, are on the same line as the start of the block.

Example:

# bad
blah do |i| foo(i)
  bar(i)
end

# bad
blah do
  |i| foo(i)
  bar(i)
end

# good
blah do |i|
  foo(i)
  bar(i)
end

# bad
blah { |i| foo(i)
  bar(i)
}

# good
blah { |i|
  foo(i)
  bar(i)
}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

This cop checks how the whens of a case expression are indented in relation to its case or end keyword.

It will register a separate offense for each misaligned when.

Example:

# If Layout/EndAlignment is set to keyword style (default)
# *case* and *end* should always be aligned to same depth,
# and therefore *when* should always be aligned to both -
# regardless of configuration.

# bad for all styles
case n
  when 0
    x * 2
  else
    y / 3
end

# good for all styles
case n
when 0
  x * 2
else
  y / 3
end

Example: EnforcedStyle: case (default)

# if EndAlignment is set to other style such as
# start_of_line (as shown below), then *when* alignment
# configuration does have an effect.

# bad
a = case n
when 0
  x * 2
else
  y / 3
end

# good
a = case n
    when 0
      x * 2
    else
      y / 3
end

Example: EnforcedStyle: end

# bad
a = case n
    when 0
      x * 2
    else
      y / 3
end

# good
a = case n
when 0
  x * 2
else
  y / 3
end

This cop checks for braces around the last parameter in a method call if the last parameter is a hash. It supports braces, no_braces and context_dependent styles.

Example: EnforcedStyle: braces

# The `braces` style enforces braces around all method
# parameters that are hashes.

# bad
some_method(x, y, a: 1, b: 2)

# good
some_method(x, y, {a: 1, b: 2})

Example: EnforcedStyle: no_braces (default)

# The `no_braces` style checks that the last parameter doesn't
# have braces around it.

# bad
some_method(x, y, {a: 1, b: 2})

# good
some_method(x, y, a: 1, b: 2)

Example: EnforcedStyle: context_dependent

# The `context_dependent` style checks that the last parameter
# doesn't have braces around it, but requires braces if the
# second to last parameter is also a hash literal.

# bad
some_method(x, y, {a: 1, b: 2})
some_method(x, y, {a: 1, b: 2}, a: 1, b: 2)

# good
some_method(x, y, a: 1, b: 2)
some_method(x, y, {a: 1, b: 2}, {a: 1, b: 2})

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 cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

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)

This cop 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

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 that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

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 double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

This cop checks how the whens of a case expression are indented in relation to its case or end keyword.

It will register a separate offense for each misaligned when.

Example:

# If Layout/EndAlignment is set to keyword style (default)
# *case* and *end* should always be aligned to same depth,
# and therefore *when* should always be aligned to both -
# regardless of configuration.

# bad for all styles
case n
  when 0
    x * 2
  else
    y / 3
end

# good for all styles
case n
when 0
  x * 2
else
  y / 3
end

Example: EnforcedStyle: case (default)

# if EndAlignment is set to other style such as
# start_of_line (as shown below), then *when* alignment
# configuration does have an effect.

# bad
a = case n
when 0
  x * 2
else
  y / 3
end

# good
a = case n
    when 0
      x * 2
    else
      y / 3
end

Example: EnforcedStyle: end

# bad
a = case n
    when 0
      x * 2
    else
      y / 3
end

# good
a = case n
when 0
  x * 2
else
  y / 3
end

This cops checks the alignment of else keywords. Normally they should be aligned with an if/unless/while/until/begin/def keyword, but there are special cases when they should follow the same rules as the alignment of end.

Example:

# bad
if something
  code
 else
  code
end

# bad
if something
  code
 elsif something
  code
end

# good
if something
  code
else
  code
end

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

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

This cops checks the alignment of else keywords. Normally they should be aligned with an if/unless/while/until/begin/def keyword, but there are special cases when they should follow the same rules as the alignment of end.

Example:

# bad
if something
  code
 else
  code
end

# bad
if something
  code
 elsif something
  code
end

# good
if something
  code
else
  code
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

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

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 that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

This cop checks for braces around the last parameter in a method call if the last parameter is a hash. It supports braces, no_braces and context_dependent styles.

Example: EnforcedStyle: braces

# The `braces` style enforces braces around all method
# parameters that are hashes.

# bad
some_method(x, y, a: 1, b: 2)

# good
some_method(x, y, {a: 1, b: 2})

Example: EnforcedStyle: no_braces (default)

# The `no_braces` style checks that the last parameter doesn't
# have braces around it.

# bad
some_method(x, y, {a: 1, b: 2})

# good
some_method(x, y, a: 1, b: 2)

Example: EnforcedStyle: context_dependent

# The `context_dependent` style checks that the last parameter
# doesn't have braces around it, but requires braces if the
# second to last parameter is also a hash literal.

# bad
some_method(x, y, {a: 1, b: 2})
some_method(x, y, {a: 1, b: 2}, a: 1, b: 2)

# good
some_method(x, y, a: 1, b: 2)
some_method(x, y, {a: 1, b: 2}, {a: 1, b: 2})

This cop checks for braces around the last parameter in a method call if the last parameter is a hash. It supports braces, no_braces and context_dependent styles.

Example: EnforcedStyle: braces

# The `braces` style enforces braces around all method
# parameters that are hashes.

# bad
some_method(x, y, a: 1, b: 2)

# good
some_method(x, y, {a: 1, b: 2})

Example: EnforcedStyle: no_braces (default)

# The `no_braces` style checks that the last parameter doesn't
# have braces around it.

# bad
some_method(x, y, {a: 1, b: 2})

# good
some_method(x, y, a: 1, b: 2)

Example: EnforcedStyle: context_dependent

# The `context_dependent` style checks that the last parameter
# doesn't have braces around it, but requires braces if the
# second to last parameter is also a hash literal.

# bad
some_method(x, y, {a: 1, b: 2})
some_method(x, y, {a: 1, b: 2}, a: 1, b: 2)

# good
some_method(x, y, a: 1, b: 2)
some_method(x, y, {a: 1, b: 2}, {a: 1, b: 2})

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

This cop checks for braces around the last parameter in a method call if the last parameter is a hash. It supports braces, no_braces and context_dependent styles.

Example: EnforcedStyle: braces

# The `braces` style enforces braces around all method
# parameters that are hashes.

# bad
some_method(x, y, a: 1, b: 2)

# good
some_method(x, y, {a: 1, b: 2})

Example: EnforcedStyle: no_braces (default)

# The `no_braces` style checks that the last parameter doesn't
# have braces around it.

# bad
some_method(x, y, {a: 1, b: 2})

# good
some_method(x, y, a: 1, b: 2)

Example: EnforcedStyle: context_dependent

# The `context_dependent` style checks that the last parameter
# doesn't have braces around it, but requires braces if the
# second to last parameter is also a hash literal.

# bad
some_method(x, y, {a: 1, b: 2})
some_method(x, y, {a: 1, b: 2}, a: 1, b: 2)

# good
some_method(x, y, a: 1, b: 2)
some_method(x, y, {a: 1, b: 2}, {a: 1, b: 2})

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for underscore-prefixed variables that are actually used.

Example:

# bad

[1, 2, 3].each do |_num|
  do_something(_num)
end

Example:

# good

[1, 2, 3].each do |num|
  do_something(num)
end

Example:

# good

[1, 2, 3].each do |_num|
  do_something # not using `_num`
end

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop looks for uses of the for keyword, or each method. The preferred alternative is set in the EnforcedStyle configuration parameter. An each call with a block on a single line is always allowed, however.

This cop checks for potential usage of the ||= operator.

Example:

# bad
name = name ? name : 'Bozhidar'

# bad
name = if name
         name
       else
         'Bozhidar'
       end

# bad
unless name
  name = 'Bozhidar'
end

# bad
name = 'Bozhidar' unless name

# good - set name to 'Bozhidar', only if it's nil or false
name ||= 'Bozhidar'

This cop 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: 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

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

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 uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

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

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for usage of comparison operators (==, >, <) to test numbers as zero, positive, or negative. These can be replaced by their respective predicate methods. The cop can also be configured to do the reverse.

The cop disregards #nonzero? as it its value is truthy or falsey, but not true and false, and thus not always interchangeable with != 0.

The cop ignores comparisons to global variables, since they are often populated with objects which can be compared with integers, but are not themselves Interger polymorphic.

Example: EnforcedStyle: predicate (default)

# bad

foo == 0
0 > foo
bar.baz > 0

# good

foo.zero?
foo.negative?
bar.baz.positive?

Example: EnforcedStyle: comparison

# bad

foo.zero?
foo.negative?
bar.baz.positive?

# good

foo == 0
0 > foo
bar.baz > 0

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 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)

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

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)

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for braces around the last parameter in a method call if the last parameter is a hash. It supports braces, no_braces and context_dependent styles.

Example: EnforcedStyle: braces

# The `braces` style enforces braces around all method
# parameters that are hashes.

# bad
some_method(x, y, a: 1, b: 2)

# good
some_method(x, y, {a: 1, b: 2})

Example: EnforcedStyle: no_braces (default)

# The `no_braces` style checks that the last parameter doesn't
# have braces around it.

# bad
some_method(x, y, {a: 1, b: 2})

# good
some_method(x, y, a: 1, b: 2)

Example: EnforcedStyle: context_dependent

# The `context_dependent` style checks that the last parameter
# doesn't have braces around it, but requires braces if the
# second to last parameter is also a hash literal.

# bad
some_method(x, y, {a: 1, b: 2})
some_method(x, y, {a: 1, b: 2}, a: 1, b: 2)

# good
some_method(x, y, a: 1, b: 2)
some_method(x, y, {a: 1, b: 2}, {a: 1, b: 2})

This cop checks for braces around the last parameter in a method call if the last parameter is a hash. It supports braces, no_braces and context_dependent styles.

Example: EnforcedStyle: braces

# The `braces` style enforces braces around all method
# parameters that are hashes.

# bad
some_method(x, y, a: 1, b: 2)

# good
some_method(x, y, {a: 1, b: 2})

Example: EnforcedStyle: no_braces (default)

# The `no_braces` style checks that the last parameter doesn't
# have braces around it.

# bad
some_method(x, y, {a: 1, b: 2})

# good
some_method(x, y, a: 1, b: 2)

Example: EnforcedStyle: context_dependent

# The `context_dependent` style checks that the last parameter
# doesn't have braces around it, but requires braces if the
# second to last parameter is also a hash literal.

# bad
some_method(x, y, {a: 1, b: 2})
some_method(x, y, {a: 1, b: 2}, a: 1, b: 2)

# good
some_method(x, y, a: 1, b: 2)
some_method(x, y, {a: 1, b: 2}, {a: 1, b: 2})

This cop 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

This cop checks for braces around the last parameter in a method call if the last parameter is a hash. It supports braces, no_braces and context_dependent styles.

Example: EnforcedStyle: braces

# The `braces` style enforces braces around all method
# parameters that are hashes.

# bad
some_method(x, y, a: 1, b: 2)

# good
some_method(x, y, {a: 1, b: 2})

Example: EnforcedStyle: no_braces (default)

# The `no_braces` style checks that the last parameter doesn't
# have braces around it.

# bad
some_method(x, y, {a: 1, b: 2})

# good
some_method(x, y, a: 1, b: 2)

Example: EnforcedStyle: context_dependent

# The `context_dependent` style checks that the last parameter
# doesn't have braces around it, but requires braces if the
# second to last parameter is also a hash literal.

# bad
some_method(x, y, {a: 1, b: 2})
some_method(x, y, {a: 1, b: 2}, a: 1, b: 2)

# good
some_method(x, y, a: 1, b: 2)
some_method(x, y, {a: 1, b: 2}, {a: 1, b: 2})

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

This cop checks for braces around the last parameter in a method call if the last parameter is a hash. It supports braces, no_braces and context_dependent styles.

Example: EnforcedStyle: braces

# The `braces` style enforces braces around all method
# parameters that are hashes.

# bad
some_method(x, y, a: 1, b: 2)

# good
some_method(x, y, {a: 1, b: 2})

Example: EnforcedStyle: no_braces (default)

# The `no_braces` style checks that the last parameter doesn't
# have braces around it.

# bad
some_method(x, y, {a: 1, b: 2})

# good
some_method(x, y, a: 1, b: 2)

Example: EnforcedStyle: context_dependent

# The `context_dependent` style checks that the last parameter
# doesn't have braces around it, but requires braces if the
# second to last parameter is also a hash literal.

# bad
some_method(x, y, {a: 1, b: 2})
some_method(x, y, {a: 1, b: 2}, a: 1, b: 2)

# good
some_method(x, y, a: 1, b: 2)
some_method(x, y, {a: 1, b: 2}, {a: 1, b: 2})

This cop checks for big numeric literals without _ between groups of digits in them.

Example:

# bad

1000000
1_00_000
1_0000

# good

1_000_000
1000

# good unless Strict is set

10_000_00 # typical representation of $10,000 in cents

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

Checks for empty else-clauses, possibly including comments and/or an explicit nil depending on the EnforcedStyle.

Example: EnforcedStyle: empty

# warn only on empty else

# bad
if condition
  statement
else
end

# good
if condition
  statement
else
  nil
end

# good
if condition
  statement
else
  statement
end

# good
if condition
  statement
end

Example: EnforcedStyle: nil

# warn on else with nil in it

# bad
if condition
  statement
else
  nil
end

# good
if condition
  statement
else
end

# good
if condition
  statement
else
  statement
end

# good
if condition
  statement
end

Example: EnforcedStyle: both (default)

# warn on empty else and else with nil in it

# bad
if condition
  statement
else
  nil
end

# bad
if condition
  statement
else
end

# good
if condition
  statement
else
  statement
end

# good
if condition
  statement
end

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Example:

# bad
!!something

# good
!something.nil?

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

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?

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 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?

This cop checks for the presence of method_missing without also defining respond_to_missing? and falling back on super.

Example:

#bad
def method_missing(name, *args)
  # ...
end

#good
def respond_to_missing?(name, include_private)
  # ...
end

def method_missing(name, *args)
  # ...
  super
end

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)

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 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 of3` 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]

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