class RuboCop::Cop::Style::HashConversion
Checks the usage of pre-2.1 ‘Hash` method of converting enumerables and sequences of values to hashes.
Correction code from splat argument (‘Hash`) is not simply determined. For
example, `Hash` can be replaced with `ary.each_slice(2).to_h` but it will be complicated. So, `AllowSplatArgument` option is true by default to allow splat argument for simple code.
@safety
This cop's autocorrection is unsafe because `ArgumentError` occurs if the number of elements is odd: [source,ruby] ---- Hash[[[1, 2], [3]]] #=> {1=>2, 3=>nil} [[1, 2], [5]].to_h #=> wrong array length at 1 (expected 2, was 1) (ArgumentError) ----
@example
# bad Hash[ary] # good ary.to_h # bad Hash[key1, value1, key2, value2] # good {key1 => value1, key2 => value2}
@example AllowSplatArgument: true (default)
# good Hash[*ary]
@example AllowSplatArgument: false
# bad Hash[*ary]
Constants
- MSG_LITERAL_HASH_ARG
- MSG_LITERAL_MULTI_ARG
- MSG_SPLAT
- MSG_TO_H
- RESTRICT_ON_SEND
Public Instance Methods
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 56 def on_send(node) return if part_of_ignored_node?(node) || !hash_from_array?(node) # There are several cases: # If there is one argument: # Hash[ary] => ary.to_h # Hash[*ary] => don't suggest corrections # If there is 0 or 2+ arguments: # Hash[a1, a2, a3, a4] => {a1 => a2, a3 => a4} # ...but don't suggest correction if there is odd number of them (it is a bug) node.arguments.one? ? single_argument(node) : multi_argument(node) ignore_node(node) end
Private Instance Methods
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 145 def allowed_splat_argument? cop_config.fetch('AllowSplatArgument', true) end
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 138 def args_to_hash(args) content = args.each_slice(2) .map { |arg1, arg2| "#{arg1.source} => #{arg2.source}" } .join(', ') "{#{content}}" end
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 123 def multi_argument(node) if node.arguments.count.odd? add_offense(node, message: MSG_LITERAL_MULTI_ARG) else add_offense(node, message: MSG_LITERAL_MULTI_ARG) do |corrector| corrector.replace(node, args_to_hash(node.arguments)) parent = node.parent if parent&.send_type? && !parent.method?(:to_h) && !parent.parenthesized? add_parentheses(parent, corrector) end end end end
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 95 def register_offense_for_hash(node, hash_argument) add_offense(node, message: MSG_LITERAL_HASH_ARG) do |corrector| corrector.replace(node, "{#{hash_argument.source}}") parent = node.parent add_parentheses(parent, corrector) if parent&.send_type? && !parent.parenthesized? end end
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 104 def register_offense_for_zip_method(node, zip_method) add_offense(node, message: MSG_TO_H) do |corrector| if zip_method.parenthesized? corrector.insert_before(zip_method.loc.end, '[]') else corrector.insert_after(zip_method, '([])') end end end
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 114 def requires_parens?(node) if node.call_type? return false if node.method?(:[]) return true if node.arguments.any? && !node.parenthesized? end node.operator_keyword? end
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 72 def single_argument(node) first_argument = node.first_argument if first_argument.hash_type? register_offense_for_hash(node, first_argument) elsif first_argument.splat_type? add_offense(node, message: MSG_SPLAT) unless allowed_splat_argument? elsif use_zip_method_without_argument?(first_argument) register_offense_for_zip_method(node, first_argument) else add_offense(node, message: MSG_TO_H) do |corrector| replacement = first_argument.source replacement = "(#{replacement})" if requires_parens?(first_argument) corrector.replace(node, "#{replacement}.to_h") end end end
Source
# File lib/rubocop/cop/style/hash_conversion.rb, line 89 def use_zip_method_without_argument?(first_argument) return false unless first_argument&.send_type? first_argument.method?(:zip) && first_argument.arguments.empty? end