class RuboCop::Cop::Lint::AmbiguousBlockAssociation

Checks for ambiguous block association with method when param passed without parentheses.

This cop can customize allowed methods with ‘AllowedMethods`. By default, there are no methods to allowed.

@example

# bad
some_method a { |val| puts val }

# good
# With parentheses, there's no ambiguity.
some_method(a { |val| puts val })
# or (different meaning)
some_method(a) { |val| puts val }

# good
# Operator methods require no disambiguation
foo == bar { |b| b.baz }

# good
# Lambda arguments require no disambiguation
foo = ->(bar) { bar.baz }

@example AllowedMethods: [] (default)

# bad
expect { do_something }.to change { object.attribute }

@example AllowedMethods: [change]

# good
expect { do_something }.to change { object.attribute }

@example AllowedPatterns: [] (default)

# bad
expect { do_something }.to change { object.attribute }

@example AllowedPatterns: [‘change’]

# good
expect { do_something }.to change { object.attribute }
expect { do_something }.to not_change { object.attribute }

Constants

MSG

Public Instance Methods

on_csend(node)
Alias for: on_send
on_send(node) click to toggle source
# File lib/rubocop/cop/lint/ambiguous_block_association.rb, line 62
def on_send(node)
  return unless node.arguments?

  return unless ambiguous_block_association?(node)
  return if node.parenthesized? || node.last_argument.lambda_or_proc? ||
            allowed_method_pattern?(node)

  message = message(node)

  add_offense(node, message: message) do |corrector|
    wrap_in_parentheses(corrector, node)
  end
end
Also aliased as: on_csend

Private Instance Methods

allowed_method_pattern?(node) click to toggle source
# File lib/rubocop/cop/lint/ambiguous_block_association.rb, line 83
def allowed_method_pattern?(node)
  node.assignment? || node.operator_method? || node.method?(:[]) ||
    allowed_method?(node.last_argument.method_name) ||
    matches_allowed_pattern?(node.last_argument.send_node.source)
end
ambiguous_block_association?(send_node) click to toggle source
# File lib/rubocop/cop/lint/ambiguous_block_association.rb, line 79
def ambiguous_block_association?(send_node)
  send_node.last_argument.block_type? && !send_node.last_argument.send_node.arguments?
end
message(send_node) click to toggle source
# File lib/rubocop/cop/lint/ambiguous_block_association.rb, line 89
def message(send_node)
  block_param = send_node.last_argument

  format(MSG, param: block_param.source, method: block_param.send_node.source)
end
wrap_in_parentheses(corrector, node) click to toggle source
# File lib/rubocop/cop/lint/ambiguous_block_association.rb, line 95
def wrap_in_parentheses(corrector, node)
  range = node.loc.selector.end.join(node.first_argument.source_range.begin)

  corrector.remove(range)
  corrector.insert_before(range, '(')
  corrector.insert_after(node.last_argument, ')')
end