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Class: RuboCop::Cop::Style::MethodCallWithArgsParentheses

Overview

Enforces the presence (default) or absence of parentheses in method calls containing arguments.

In the default style (require_parentheses), macro methods are allowed. Additional methods can be added to the AllowedMethods or AllowedPatterns list. These options are valid only in the default style. Macros can be included by either setting IgnoreMacros to false or adding specific macros to the IncludedMacros list.

Precedence of options is as follows:

  1. AllowedMethods

  2. AllowedPatterns

  3. IncludedMacros

If a method is listed in both IncludedMacros and AllowedMethods, then the latter takes precedence (that is, the method is allowed).

In the alternative style (omit_parentheses), there are three additional options.

  1. AllowParenthesesInChaining is false by default. Setting it to true allows the presence of parentheses in the last call during method chaining.

  2. AllowParenthesesInMultilineCall is false by default. Setting it to true allows the presence of parentheses in multi-line method calls.

  3. AllowParenthesesInCamelCaseMethod is false by default. This allows the presence of parentheses when calling a method whose name begins with a capital letter and which has no arguments. Setting it to true allows the presence of parentheses in such a method call even with arguments.

Note
The style of omit_parentheses allows parentheses in cases where omitting them results in ambiguous or syntactically incorrect code.

Non-exhaustive list of examples:

  • Parentheses are required allowed in method calls with arguments inside literals, logical operators, setting default values in position and keyword arguments, chaining and more.

  • Parentheses are allowed in method calls with arguments inside operators to avoid ambiguity. triple-dot syntax introduced in Ruby 2.7 as omitting them starts an endless range.

  • Parentheses are allowed when forwarding arguments with the triple-dot syntax introduced in Ruby 2.7 as omitting them starts an endless range.

  • Parentheses are required in calls with arguments when inside an endless method definition introduced in Ruby 3.0.

  • Ruby 3.1’s hash omission syntax allows parentheses if the method call is in conditionals and requires parentheses if the call is not the value-returning expression. See https://bugs.ruby-lang.org/issues/18396.

  • Parentheses are required in anonymous arguments, keyword arguments and block passing in Ruby 3.2.

Examples:

EnforcedStyle: require_parentheses (default)

# bad
array.delete e

# good
array.delete(e)

# good
# Operators don't need parens
foo == bar

# good
# Setter methods don't need parens
foo.bar = baz

# okay with `puts` listed in `AllowedMethods`
puts 'test'

# okay with `^assert` listed in `AllowedPatterns`
assert_equal 'test', x

EnforcedStyle: omit_parentheses

# bad
array.delete(e)

# good
array.delete e

# bad
action.enforce(strict: true)

# good
action.enforce strict: true

# good
# Parentheses are allowed for code that can be ambiguous without
# them.
action.enforce(condition) || other_condition

# good
# Parentheses are allowed for calls that won't produce valid Ruby
# without them.
yield path, File.basename(path)

# good
# Omitting the parentheses in Ruby 3.1 hash omission syntax can lead
# to ambiguous code. We allow them in conditionals and non-last
# expressions. See https://bugs.ruby-lang.org/issues/18396
if meets(criteria:, action:)
  safe_action(action) || dangerous_action(action)
end

IgnoreMacros: true (default)

# good
class Foo
  bar :baz
end

IgnoreMacros: false

# bad
class Foo
  bar :baz
end

AllowParenthesesInMultilineCall: false (default)

# bad
foo.enforce(
  strict: true
)

# good
foo.enforce \
  strict: true

AllowParenthesesInMultilineCall: true

# good
foo.enforce(
  strict: true
)

# good
foo.enforce \
  strict: true

AllowParenthesesInChaining: false (default)

# bad
foo().bar(1)

# good
foo().bar 1

AllowParenthesesInChaining: true

# good
foo().bar(1)

# good
foo().bar 1

AllowParenthesesInCamelCaseMethod: false (default)

# bad
Array(1)

# good
Array 1

AllowParenthesesInCamelCaseMethod: true

# good
Array(1)

# good
Array 1

AllowParenthesesInStringInterpolation: false (default)

# bad
"#{t('this.is.bad')}"

# good
"#{t 'this.is.better'}"

AllowParenthesesInStringInterpolation: true

# good
"#{t('this.is.good')}"

# good
"#{t 'this.is.also.good'}"

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

SYMBOL_TO_STRING_CACHE

RequireParentheses - Included

REQUIRE_MSG

OmitParentheses - Included

OMIT_MSG, TRAILING_WHITESPACE_REGEX

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns an url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

OmitParentheses - Included

RequireParentheses - Included

::RuboCop::Cop::AllowedPattern - Included

::RuboCop::Cop::AllowedMethods - Included

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Class Method Details

.autocorrect_incompatible_with

[ GitHub ]

  
# File 'lib/rubocop/cop/style/method_call_with_args_parentheses.rb', line 213

def self.autocorrect_incompatible_with
  [Style::NestedParenthesizedCalls, Style::RescueModifier]
end

Instance Method Details

#args_begin(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/method_call_with_args_parentheses.rb', line 225

def args_begin(node)
  loc = node.loc
  selector = node.yield_type? ? loc.keyword : loc.selector

  resize_by = args_parenthesized?(node) ? 2 : 1
  selector.end.resize(resize_by)
end

#args_end(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/method_call_with_args_parentheses.rb', line 233

def args_end(node)
  node.source_range.end
end

#args_parenthesized?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/method_call_with_args_parentheses.rb', line 237

def args_parenthesized?(node)
  return false unless node.arguments.one?

  first_node = node.first_argument
  first_node.begin_type? && first_node.parenthesized_call?
end

#on_csend(node)

Alias for #on_send.

[ GitHub ]

  
# File 'lib/rubocop/cop/style/method_call_with_args_parentheses.rb', line 220

alias on_csend on_send

#on_send(node) Also known as: #on_csend, #on_yield

[ GitHub ]

  
# File 'lib/rubocop/cop/style/method_call_with_args_parentheses.rb', line 217

def on_send(node)
  send(style, node) # call require_parentheses or omit_parentheses
end

#on_yield(node)

Alias for #on_send.

[ GitHub ]

  
# File 'lib/rubocop/cop/style/method_call_with_args_parentheses.rb', line 221

alias on_yield on_send