class RuboCop::Cop::Lint::AmbiguousRange
Checks for ambiguous ranges.
Ranges have quite low precedence, which leads to unexpected behavior when using a range with other operators. This cop avoids that by making ranges explicit by requiring parenthesis around complex range boundaries (anything that is not a literal: numerics, strings, symbols, etc.).
This cop can be configured with ‘RequireParenthesesForMethodChains` in order to specify whether method chains (including `self.foo`) should be wrapped in parens by this cop.
NOTE: Regardless of this configuration, if a method receiver is a basic literal value, it will be wrapped in order to prevent the ambiguity of ‘1..2.to_a`.
@safety
The cop autocorrects by wrapping the entire boundary in parentheses, which makes the outcome more explicit but is possible to not be the intention of the programmer. For this reason, this cop's autocorrect is unsafe (it will not change the behavior of the code, but will not necessarily match the intent of the program).
@example
# bad x || 1..2 x - 1..2 (x || 1..2) x || 1..y || 2 1..2.to_a # good, unambiguous 1..2 'a'..'z' :bar..:baz MyClass::MIN..MyClass::MAX @min..@max a..b -a..b # good, ambiguity removed x || (1..2) (x - 1)..2 (x || 1)..2 (x || 1)..(y || 2) (1..2).to_a
@example RequireParenthesesForMethodChains: false (default)
# good a.foo..b.bar (a.foo)..(b.bar)
@example RequireParenthesesForMethodChains: true
# bad a.foo..b.bar # good (a.foo)..(b.bar)
Constants
- MSG
Public Instance Methods
Source
# File lib/rubocop/cop/lint/ambiguous_range.rb, line 68 def on_irange(node) each_boundary(node) do |boundary| next if acceptable?(boundary) add_offense(boundary) do |corrector| corrector.wrap(boundary, '(', ')') end end end
Private Instance Methods
Source
# File lib/rubocop/cop/lint/ambiguous_range.rb, line 87 def acceptable?(node) node.begin_type? || node.literal? || rational_literal?(node) || node.variable? || node.const_type? || node.self_type? || (node.call_type? && acceptable_call?(node)) end
rubocop:disable Metrics/CyclomaticComplexity
Source
# File lib/rubocop/cop/lint/ambiguous_range.rb, line 95 def acceptable_call?(node) return true if node.unary_operation? # Require parentheses when making a method call on a literal # to avoid the ambiguity of `1..2.to_a`. return false if node.receiver&.basic_literal? return false if node.operator_method? && !node.method?(:[]) require_parentheses_for_method_chain? || node.receiver.nil? end
rubocop:enable Metrics/CyclomaticComplexity
Source
# File lib/rubocop/cop/lint/ambiguous_range.rb, line 81 def each_boundary(range) yield range.begin if range.begin yield range.end if range.end end
Source
# File lib/rubocop/cop/lint/ambiguous_range.rb, line 107 def require_parentheses_for_method_chain? !cop_config['RequireParenthesesForMethodChains'] end