Class: RuboCop::Cop::Style::SymbolProc

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
CommentsHelp, IgnoredMethods, RangeHelp
Defined in:
lib/rubocop/cop/style/symbol_proc.rb

Overview

Use symbols as procs when possible.

If you prefer a style that allows block for method with arguments, please set true to AllowMethodsWithArguments.

Examples:

# bad
something.map { |s| s.upcase }
something.map { _1.upcase }

# good
something.map(&:upcase)

AllowMethodsWithArguments: false (default)

# bad
something.do_something(foo) { |o| o.bar }

# good
something.do_something(foo, &:bar)

AllowMethodsWithArguments: true

# good
something.do_something(foo) { |o| o.bar }

AllowComments: false (default)

# bad
something.do_something do |s| # some comment
  # some comment
  s.upcase # some comment
  # some comment
end

AllowComments: true

# good  - if there are comment in either position
something.do_something do |s| # some comment
  # some comment
  s.upcase # some comment
  # some comment
end

Cop Safety Information:

  • This cop is unsafe because procs and blocks work differently when additional arguments are passed in. A block will silently ignore additional arguments, but a proc will raise an ArgumentError.

    For example:

    [source,ruby]

    class Foo def bar :bar end end

    def call(options = {}, &block) block.call(Foo.new, options) end

    call { |x| x.bar }

    => :bar

    call(&:bar)

    ArgumentError: wrong number of arguments (given 1, expected 0)


Constant Summary collapse

MSG =
'Pass `&:%<method>s` as an argument to `%<block_method>s` instead of a block.'
SUPER_TYPES =
%i[super zsuper].freeze

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Class Method Summary collapse

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods included from IgnoredMethods

#ignored_method?, #ignored_methods, included

Methods included from CommentsHelp

#contains_comments?, #source_range_with_comment

Methods inherited from Base

#add_global_offense, #add_offense, badge, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Class Method Details

.autocorrect_incompatible_withObject


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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 94

def self.autocorrect_incompatible_with
  [Layout::SpaceBeforeBlockBraces]
end

Instance Method Details

#destructuring_block_argument?(argument_node) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 117

def destructuring_block_argument?(argument_node)
  argument_node.one? && argument_node.source.include?(',')
end

#on_block(node) ⇒ Object Also known as: on_numblock

rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity


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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 99

def on_block(node)
  symbol_proc?(node) do |dispatch_node, arguments_node, method_name|
    # TODO: Rails-specific handling that we should probably make
    # configurable - https://github.com/rubocop/rubocop/issues/1485
    # we should ignore lambdas & procs
    return if proc_node?(dispatch_node)
    return if %i[lambda proc].include?(dispatch_node.method_name)
    return if ignored_method?(dispatch_node.method_name)
    return if allow_if_method_has_argument?(node)
    return if node.block_type? && destructuring_block_argument?(arguments_node)
    return if allow_comments? && contains_comments?(node)

    register_offense(node, method_name, dispatch_node.method_name)
  end
end

#proc_node?(node) ⇒ Object


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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 81

def_node_matcher :proc_node?, '(send (const {nil? cbase} :Proc) :new)'

#symbol_proc?(node) ⇒ Object


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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 87

def_node_matcher :symbol_proc?, <<~PATTERN
  {
    (block $#symbol_proc_receiver? $(args (arg _var)) (send (lvar _var) $_))
    (numblock $#symbol_proc_receiver? $1 (send (lvar :_1) $_))
  }
PATTERN

#symbol_proc_receiver?(node) ⇒ Object


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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 84

def_node_matcher :symbol_proc_receiver?, '{(send ...) (super ...) zsuper}'