Class: RuboCop::Cop::Style::EmptyLiteral
- Defined in:
- lib/rubocop/cop/style/empty_literal.rb
Overview
This cop checks for the use of a method, the result of which would be a literal, like an empty array, hash or string.
Constant Summary collapse
- ARR_MSG =
'Use array literal `[]` instead of `Array.new`.'
- HASH_MSG =
'Use hash literal `{}` instead of `Hash.new`.'
- STR_MSG =
"Use string literal `''` instead of `String.new`."
- ARRAY_NODE =
Empty array node
(send (const nil :Array) :new)
s(:send, s(:const, nil, :Array), :new)
- HASH_NODE =
Empty hash node
(send (const nil :Hash) :new)
s(:send, s(:const, nil, :Hash), :new)
- STR_NODE =
Empty string node
(send (const nil :String) :new)
s(:send, s(:const, nil, :String), :new)
Constants included from Util
Util::ASGN_NODES, Util::EQUALS_ASGN_NODES, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, Util::SHORTHAND_ASGN_NODES
Instance Attribute Summary
Attributes inherited from Cop
#config, #corrections, #offenses, #processed_source
Instance Method Summary collapse
- #autocorrect(node) ⇒ Object
- #first_arg_in_method_call_without_parentheses?(node) ⇒ Boolean
- #on_send(node) ⇒ Object
Methods inherited from Cop
#add_offense, all, #autocorrect?, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, cop_name_with_namespace, cop_type, #debug?, #display_cop_names?, inherited, #initialize, #join_force?, lint?, #message, non_rails, qualified_cop_name, rails?, #relevant_file?, #support_autocorrect?
Methods included from IgnoredNode
#ignore_node, #ignored_node?, #part_of_ignored_node?
Methods included from Util
begins_its_line?, block_length, command?, comment_line?, const_name, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, within_node?
Methods included from PathUtil
issue_deprecation_warning, match_path?, relative_path
Constructor Details
This class inherits a constructor from RuboCop::Cop::Cop
Instance Method Details
#autocorrect(node) ⇒ Object
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# File 'lib/rubocop/cop/style/empty_literal.rb', line 45 def autocorrect(node) name = case node when ARRAY_NODE '[]' when HASH_NODE # `some_method {}` is not same as `some_method Hash.new` # because the braces are interpreted as a block, so we avoid # the correction. Parentheses around the arguments would # solve the problem, but we let the user add those manually. if first_arg_in_method_call_without_parentheses?(node) fail CorrectionNotPossible end '{}' when STR_NODE "''" end @corrections << lambda do |corrector| corrector.replace(node.loc.expression, name) end end |
#first_arg_in_method_call_without_parentheses?(node) ⇒ Boolean
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# File 'lib/rubocop/cop/style/empty_literal.rb', line 66 def first_arg_in_method_call_without_parentheses?(node) return false unless node.parent && node.parent.send_type? _receiver, _method_name, *args = *node.parent node.object_id == args.first.object_id && !parentheses?(node.parent) end |
#on_send(node) ⇒ Object
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# File 'lib/rubocop/cop/style/empty_literal.rb', line 31 def on_send(node) case node when ARRAY_NODE add_offense(node, :expression, ARR_MSG) when HASH_NODE # If Hash.new takes a block, it can't be changed to {}. return if node.parent && node.parent.block_type? add_offense(node, :expression, HASH_MSG) when STR_NODE add_offense(node, :expression, STR_MSG) end end |