class RuboCop::Cop::Naming::BlockForwarding
In Ruby 3.1, anonymous block forwarding has been added.
This cop identifies places where ‘do_something(&block)` can be replaced by `do_something(&)`.
It also supports the opposite style by alternative ‘explicit` option. You can specify the block variable name for autocorrection with `BlockForwardingName`. The default variable name is `block`. If the name is already in use, it will not be autocorrected.
- NOTE
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¶ ↑
Because of a bug in Ruby 3.3.0, when a block is referenced inside of another block, no offense will be registered until Ruby 3.4:
- source,ruby
def foo(&block)
# Using an anonymous block would be a syntax error on Ruby 3.3.0 block_method { bar(&block) }
end
¶ ↑
@example EnforcedStyle: anonymous (default)
# bad def foo(&block) bar(&block) end # good def foo(&) bar(&) end
@example EnforcedStyle: explicit
# bad def foo(&) bar(&) end # good def foo(&block) bar(&block) end
Constants
- MSG
Public Class Methods
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 64 def self.autocorrect_incompatible_with [Lint::AmbiguousOperator, Style::ArgumentsForwarding, Style::ExplicitBlockArgument] end
Public Instance Methods
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 68 def on_def(node) return if node.arguments.empty? last_argument = node.last_argument return if expected_block_forwarding_style?(node, last_argument) forwarded_args = node.each_descendant(:block_pass).with_object([]) do |block_pass, result| return nil if invalidates_syntax?(block_pass) next unless block_argument_name_matched?(block_pass, last_argument) result << block_pass end forwarded_args.each do |forwarded_arg| register_offense(forwarded_arg, node) end register_offense(last_argument, node) end
Private Instance Methods
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 118 def anonymous_block_argument?(node) node.blockarg_type? && node.name.nil? end
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 101 def block_argument_name_matched?(block_pass_node, last_argument) return false if block_pass_node.children.first&.sym_type? last_argument.source == block_pass_node.source end
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 150 def block_forwarding_name cop_config.fetch('BlockForwardingName', 'block') end
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 91 def expected_block_forwarding_style?(node, last_argument) if style == :anonymous !explicit_block_argument?(last_argument) || use_kwarg_in_method_definition?(node) || use_block_argument_as_local_variable?(node, last_argument.source[1..]) else !anonymous_block_argument?(last_argument) end end
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 122 def explicit_block_argument?(node) node.blockarg_type? && !node.name.nil? end
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 110 def invalidates_syntax?(block_pass_node) target_ruby_version <= 3.3 && block_pass_node.each_ancestor(:any_block).any? end
Ruby 3.3.0 had a bug where accessing an anonymous block argument inside of a block was a syntax error in unambiguous cases: bugs.ruby-lang.org/issues/20090 We disallow this also for earlier Ruby versions so that code is forwards compatible.
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 126 def register_offense(block_argument, node) add_offense(block_argument, message: format(MSG, style: style)) do |corrector| if style == :anonymous corrector.replace(block_argument, '&') arguments = block_argument.parent add_parentheses(arguments, corrector) unless arguments.parenthesized_call? else unless use_block_argument_as_local_variable?(node, block_forwarding_name) corrector.replace(block_argument, "&#{block_forwarding_name}") end end end end
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 142 def use_block_argument_as_local_variable?(node, last_argument) return false if node.body.nil? node.body.each_node(:lvar, :lvasgn).any? do |lvar| !lvar.parent.block_pass_type? && lvar.node_parts[0].to_s == last_argument end end
Source
# File lib/rubocop/cop/naming/block_forwarding.rb, line 114 def use_kwarg_in_method_definition?(node) node.arguments.each_descendant(:kwarg, :kwoptarg).any? end