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

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

class Foo
  ARRAY = [         # +1
    1,
    2
  ]

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

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

NOTE: This cop also applies for Struct definitions.

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 the length of lines in the source code. The maximum length is configurable. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop. It also ignores a shebang line by default.

This cop has some autocorrection capabilities. It can programmatically shorten certain long lines by inserting line breaks into expressions that can be safely split across lines. These include arrays, hashes, and method calls with argument lists.

If autocorrection is enabled, the following Layout cops are recommended to further format the broken lines. (Many of these are enabled by default.)

• ArgumentAlignment
• BlockAlignment
• BlockDelimiters
• BlockEndNewline
• ClosingParenthesisIndentation
• FirstArgumentIndentation
• FirstArrayElementIndentation
• FirstHashElementIndentation
• FirstParameterIndentation
• HashAlignment
• IndentationWidth
• MultilineArrayLineBreaks
• MultilineBlockLayout
• MultilineHashBraceLayout
• MultilineHashKeyLineBreaks
• MultilineMethodArgumentLineBreaks
• ParameterAlignment

Together, these cops will pretty print hashes, arrays, method calls, etc. For example, let's say the max columns is 25:

Example:

# bad
{foo: "0000000000", bar: "0000000000", baz: "0000000000"}

# good
{foo: "0000000000",
bar: "0000000000", baz: "0000000000"}

# good (with recommended cops enabled)
{
  foo: "0000000000",
  bar: "0000000000",
  baz: "0000000000",
}

This cop checks the length of lines in the source code. The maximum length is configurable. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop. It also ignores a shebang line by default.

This cop has some autocorrection capabilities. It can programmatically shorten certain long lines by inserting line breaks into expressions that can be safely split across lines. These include arrays, hashes, and method calls with argument lists.

If autocorrection is enabled, the following Layout cops are recommended to further format the broken lines. (Many of these are enabled by default.)

• ArgumentAlignment
• BlockAlignment
• BlockDelimiters
• BlockEndNewline
• ClosingParenthesisIndentation
• FirstArgumentIndentation
• FirstArrayElementIndentation
• FirstHashElementIndentation
• FirstParameterIndentation
• HashAlignment
• IndentationWidth
• MultilineArrayLineBreaks
• MultilineBlockLayout
• MultilineHashBraceLayout
• MultilineHashKeyLineBreaks
• MultilineMethodArgumentLineBreaks
• ParameterAlignment

Together, these cops will pretty print hashes, arrays, method calls, etc. For example, let's say the max columns is 25:

Example:

# bad
{foo: "0000000000", bar: "0000000000", baz: "0000000000"}

# good
{foo: "0000000000",
bar: "0000000000", baz: "0000000000"}

# good (with recommended cops enabled)
{
  foo: "0000000000",
  bar: "0000000000",
  baz: "0000000000",
}

This cop checks the length of lines in the source code. The maximum length is configurable. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop. It also ignores a shebang line by default.

This cop has some autocorrection capabilities. It can programmatically shorten certain long lines by inserting line breaks into expressions that can be safely split across lines. These include arrays, hashes, and method calls with argument lists.

If autocorrection is enabled, the following Layout cops are recommended to further format the broken lines. (Many of these are enabled by default.)

• ArgumentAlignment
• BlockAlignment
• BlockDelimiters
• BlockEndNewline
• ClosingParenthesisIndentation
• FirstArgumentIndentation
• FirstArrayElementIndentation
• FirstHashElementIndentation
• FirstParameterIndentation
• HashAlignment
• IndentationWidth
• MultilineArrayLineBreaks
• MultilineBlockLayout
• MultilineHashBraceLayout
• MultilineHashKeyLineBreaks
• MultilineMethodArgumentLineBreaks
• ParameterAlignment

Together, these cops will pretty print hashes, arrays, method calls, etc. For example, let's say the max columns is 25:

Example:

# bad
{foo: "0000000000", bar: "0000000000", baz: "0000000000"}

# good
{foo: "0000000000",
bar: "0000000000", baz: "0000000000"}

# good (with recommended cops enabled)
{
  foo: "0000000000",
  bar: "0000000000",
  baz: "0000000000",
}

This cop checks the length of lines in the source code. The maximum length is configurable. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop. It also ignores a shebang line by default.

This cop has some autocorrection capabilities. It can programmatically shorten certain long lines by inserting line breaks into expressions that can be safely split across lines. These include arrays, hashes, and method calls with argument lists.

If autocorrection is enabled, the following Layout cops are recommended to further format the broken lines. (Many of these are enabled by default.)

• ArgumentAlignment
• BlockAlignment
• BlockDelimiters
• BlockEndNewline
• ClosingParenthesisIndentation
• FirstArgumentIndentation
• FirstArrayElementIndentation
• FirstHashElementIndentation
• FirstParameterIndentation
• HashAlignment
• IndentationWidth
• MultilineArrayLineBreaks
• MultilineBlockLayout
• MultilineHashBraceLayout
• MultilineHashKeyLineBreaks
• MultilineMethodArgumentLineBreaks
• ParameterAlignment

Together, these cops will pretty print hashes, arrays, method calls, etc. For example, let's say the max columns is 25:

Example:

# bad
{foo: "0000000000", bar: "0000000000", baz: "0000000000"}

# good
{foo: "0000000000",
bar: "0000000000", baz: "0000000000"}

# good (with recommended cops enabled)
{
  foo: "0000000000",
  bar: "0000000000",
  baz: "0000000000",
}

This cop checks the length of lines in the source code. The maximum length is configurable. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop. It also ignores a shebang line by default.

This cop has some autocorrection capabilities. It can programmatically shorten certain long lines by inserting line breaks into expressions that can be safely split across lines. These include arrays, hashes, and method calls with argument lists.

If autocorrection is enabled, the following Layout cops are recommended to further format the broken lines. (Many of these are enabled by default.)

• ArgumentAlignment
• BlockAlignment
• BlockDelimiters
• BlockEndNewline
• ClosingParenthesisIndentation
• FirstArgumentIndentation
• FirstArrayElementIndentation
• FirstHashElementIndentation
• FirstParameterIndentation
• HashAlignment
• IndentationWidth
• MultilineArrayLineBreaks
• MultilineBlockLayout
• MultilineHashBraceLayout
• MultilineHashKeyLineBreaks
• MultilineMethodArgumentLineBreaks
• ParameterAlignment

Together, these cops will pretty print hashes, arrays, method calls, etc. For example, let's say the max columns is 25:

Example:

# bad
{foo: "0000000000", bar: "0000000000", baz: "0000000000"}

# good
{foo: "0000000000",
bar: "0000000000", baz: "0000000000"}

# good (with recommended cops enabled)
{
  foo: "0000000000",
  bar: "0000000000",
  baz: "0000000000",
}

This cop checks the length of lines in the source code. The maximum length is configurable. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop. It also ignores a shebang line by default.

This cop has some autocorrection capabilities. It can programmatically shorten certain long lines by inserting line breaks into expressions that can be safely split across lines. These include arrays, hashes, and method calls with argument lists.

If autocorrection is enabled, the following Layout cops are recommended to further format the broken lines. (Many of these are enabled by default.)

• ArgumentAlignment
• BlockAlignment
• BlockDelimiters
• BlockEndNewline
• ClosingParenthesisIndentation
• FirstArgumentIndentation
• FirstArrayElementIndentation
• FirstHashElementIndentation
• FirstParameterIndentation
• HashAlignment
• IndentationWidth
• MultilineArrayLineBreaks
• MultilineBlockLayout
• MultilineHashBraceLayout
• MultilineHashKeyLineBreaks
• MultilineMethodArgumentLineBreaks
• ParameterAlignment

Together, these cops will pretty print hashes, arrays, method calls, etc. For example, let's say the max columns is 25:

Example:

# bad
{foo: "0000000000", bar: "0000000000", baz: "0000000000"}

# good
{foo: "0000000000",
bar: "0000000000", baz: "0000000000"}

# good (with recommended cops enabled)
{
  foo: "0000000000",
  bar: "0000000000",
  baz: "0000000000",
}

This cop checks the length of lines in the source code. The maximum length is configurable. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop. It also ignores a shebang line by default.

This cop has some autocorrection capabilities. It can programmatically shorten certain long lines by inserting line breaks into expressions that can be safely split across lines. These include arrays, hashes, and method calls with argument lists.

If autocorrection is enabled, the following Layout cops are recommended to further format the broken lines. (Many of these are enabled by default.)

• ArgumentAlignment
• BlockAlignment
• BlockDelimiters
• BlockEndNewline
• ClosingParenthesisIndentation
• FirstArgumentIndentation
• FirstArrayElementIndentation
• FirstHashElementIndentation
• FirstParameterIndentation
• HashAlignment
• IndentationWidth
• MultilineArrayLineBreaks
• MultilineBlockLayout
• MultilineHashBraceLayout
• MultilineHashKeyLineBreaks
• MultilineMethodArgumentLineBreaks
• ParameterAlignment

Together, these cops will pretty print hashes, arrays, method calls, etc. For example, let's say the max columns is 25:

Example:

# bad
{foo: "0000000000", bar: "0000000000", baz: "0000000000"}

# good
{foo: "0000000000",
bar: "0000000000", baz: "0000000000"}

# good (with recommended cops enabled)
{
  foo: "0000000000",
  bar: "0000000000",
  baz: "0000000000",
}

This cop checks the length of lines in the source code. The maximum length is configurable. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop. It also ignores a shebang line by default.

This cop has some autocorrection capabilities. It can programmatically shorten certain long lines by inserting line breaks into expressions that can be safely split across lines. These include arrays, hashes, and method calls with argument lists.

If autocorrection is enabled, the following Layout cops are recommended to further format the broken lines. (Many of these are enabled by default.)

• ArgumentAlignment
• BlockAlignment
• BlockDelimiters
• BlockEndNewline
• ClosingParenthesisIndentation
• FirstArgumentIndentation
• FirstArrayElementIndentation
• FirstHashElementIndentation
• FirstParameterIndentation
• HashAlignment
• IndentationWidth
• MultilineArrayLineBreaks
• MultilineBlockLayout
• MultilineHashBraceLayout
• MultilineHashKeyLineBreaks
• MultilineMethodArgumentLineBreaks
• ParameterAlignment

Together, these cops will pretty print hashes, arrays, method calls, etc. For example, let's say the max columns is 25:

Example:

# bad
{foo: "0000000000", bar: "0000000000", baz: "0000000000"}

# good
{foo: "0000000000",
bar: "0000000000", baz: "0000000000"}

# good (with recommended cops enabled)
{
  foo: "0000000000",
  bar: "0000000000",
  baz: "0000000000",
}

This cop 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 if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
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 makes sure that predicates are named properly.

Example:

# bad
def is_even(value)
end

def is_even?(value)
end

# good
def even?(value)
end

# bad
def has_value
end

def has_value?
end

# good
def value?
end

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
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 parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

This cop checks whether some constant value isn't a mutable literal (e.g. array or hash).

Strict mode can be used to freeze all constants, rather than just literals. Strict mode is considered an experimental feature. It has not been updated with an exhaustive list of all methods that will produce frozen objects so there is a decent chance of getting some false positives. Luckily, there is no harm in freezing an already frozen object.

From Ruby 3.0, this cop honours the magic comment 'shareableconstantvalue'. When this magic comment is set to any acceptable value other than none, it will suppress the offenses raised by this cop. It enforces frozen state.

NOTE: Regexp and Range literals are frozen objects since Ruby 3.0.

NOTE: From Ruby 3.0, interpolated strings are not frozen when # frozen-string-literal: true is used, so this cop enforces explicit freezing for such strings.

NOTE: From Ruby 3.0, this cop allows explicit freezing of constants when the shareable_constant_value directive is used.

Safety:

This cop's autocorrection is unsafe since any mutations on objects that are made frozen will change from being accepted to raising FrozenError, and will need to be manually refactored.

Example: EnforcedStyle: literals (default)

# bad
CONST = [1, 2, 3]

# good
CONST = [1, 2, 3].freeze

# good
CONST = <<~TESTING.freeze
  This is a heredoc
TESTING

# good
CONST = Something.new

Example: EnforcedStyle: strict

# bad
CONST = Something.new

# bad
CONST = Struct.new do
  def foo
    puts 1
  end
end

# good
CONST = Something.new.freeze

# good
CONST = Struct.new do
  def foo
    puts 1
  end
end.freeze

Example:

# Magic comment - shareable_constant_value: literal

# bad
CONST = [1, 2, 3]

# good
# shareable_constant_value: literal
CONST = [1, 2, 3]

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks 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 parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

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 of 3 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]

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

This cop checks for missing top-level documentation of classes and modules. Classes with no body are exempt from the check and so are namespace modules - modules that have nothing in their bodies except classes, other modules, 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

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
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 of 3 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]

This cop 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

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

This cop checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.

This cop does not consider endless methods, since parentheses are always required for them.

Example: EnforcedStyle: require_parentheses (default)

# The `require_parentheses` style requires method definitions
# to always use parentheses

# bad
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Example: EnforcedStyle: requirenoparentheses

# The `require_no_parentheses` style requires method definitions
# to never use parentheses

# bad
def bar(num1, num2)
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

Example: EnforcedStyle: requirenoparenthesesexceptmultiline

# The `require_no_parentheses_except_multiline` style prefers no
# parentheses when method definition arguments fit on single line,
# but prefers parentheses when arguments span multiple lines.

# bad
def bar(num1, num2)
  num1 + num2
end

def foo descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name
  do_something
end

# good
def bar num1, num2
  num1 + num2
end

def foo(descriptive_var_name,
        another_descriptive_var_name,
        last_descriptive_var_name)
  do_something
end

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

Checks for if and unless statements that would fit on one line if written as modifier if/unless. The cop also checks for modifier if/unless lines that exceed the maximum line length.

The maximum line length is configured in the Layout/LineLength cop. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop.

Example:

# bad
if condition
  do_stuff(bar)
end

unless qux.empty?
  Foo.do_something
end

do_something_with_a_long_name(arg) if long_condition_that_prevents_code_fit_on_single_line

# good
do_stuff(bar) if condition
Foo.do_something unless qux.empty?

if long_condition_that_prevents_code_fit_on_single_line
  do_something_with_a_long_name(arg)
end

if short_condition # a long comment that makes it too long if it were just a single line
  do_something
end

This cop checks the args passed to fail and raise. For exploded style (default), it recommends passing the exception class and message to raise, rather than construct an instance of the error. It will still allow passing just a message, or the construction of an error with more than one argument.

The exploded style works identically, but with the addition that it will also suggest constructing error objects when the exception is passed multiple arguments.

The exploded style has an AllowedCompactTypes configuration option that takes an Array of exception name Strings.

Example: EnforcedStyle: exploded (default)

# bad
raise StandardError.new('message')

# good
raise StandardError, 'message'
fail 'message'
raise MyCustomError
raise MyCustomError.new(arg1, arg2, arg3)
raise MyKwArgError.new(key1: val1, key2: val2)

# With `AllowedCompactTypes` set to ['MyWrappedError']
raise MyWrappedError.new(obj)
raise MyWrappedError.new(obj), 'message'

Example: EnforcedStyle: compact

# bad
raise StandardError, 'message'
raise RuntimeError, arg1, arg2, arg3

# good
raise StandardError.new('message')
raise MyCustomError
raise MyCustomError.new(arg1, arg2, arg3)
fail 'message'

This cop can check for array literals made up of word-like strings, that are not using the %w() syntax.

Alternatively, it can check for uses of the %w() syntax, in projects which do not want to include that syntax.

NOTE: When using the percent style, %w() arrays containing a space will be registered as offenses.

Configuration option: MinSize If set, arrays with fewer elements than this value will not trigger the cop. For example, a MinSize of 3 will not enforce a style on an array of 2 or fewer elements.

Example: EnforcedStyle: percent (default)

# good
%w[foo bar baz]

# bad
['foo', 'bar', 'baz']

# bad (contains spaces)
%w[foo\ bar baz\ quux]

Example: EnforcedStyle: brackets

# good
['foo', 'bar', 'baz']

# bad
%w[foo bar baz]

# good (contains spaces)
['foo bar', 'baz quux']