Class: RuboCop::Cop::Lint::Void
Relationships & Source Files | |
Super Chains via Extension / Inclusion / Inheritance | |
Class Chain:
self,
::RuboCop::Cop::AutoCorrector ,
::RuboCop::Cop::Base ,
::RuboCop::ExcludeLimit ,
NodePattern::Macros,
RuboCop::AST::Sexp
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|
Instance Chain:
self,
::RuboCop::Cop::RangeHelp ,
::RuboCop::Cop::Base ,
::RuboCop::Cop::AutocorrectLogic ,
::RuboCop::Cop::IgnoredNode ,
::RuboCop::Util ,
RuboCop::AST::Sexp
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Inherits: |
RuboCop::Cop::Base
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Defined in: | lib/rubocop/cop/lint/void.rb |
Overview
Checks for operators, variables, literals, lambda, proc and nonmutating methods used in void context.
each
blocks are allowed to prevent false positives.
For example, the expression inside the each
block below.
It’s not void, especially when the receiver is an Enumerator
:
enumerator = [1, 2, 3].filter
enumerator.each { |item| item >= 2 } #=> [2, 3]
Note
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Return values in assignment method definitions such as def foo=(arg) are
detected because they are in a void context. However, autocorrection does not remove
the return value, as that would change behavior. In such cases, whether to remove
the return value or rename the method to something more appropriate should be left to
the user.
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Constant Summary
-
BINARY_OPERATORS =
# File 'lib/rubocop/cop/lint/void.rb', line 72%i[* / % + - == === != < > <= >= <=>].freeze
-
CONST_MSG =
# File 'lib/rubocop/cop/lint/void.rb', line 66'Constant `%<var>s` used in void context.'
-
EXPRESSION_MSG =
# File 'lib/rubocop/cop/lint/void.rb', line 69'`%<expression>s` used in void context.'
-
LIT_MSG =
# File 'lib/rubocop/cop/lint/void.rb', line 67'Literal `%<lit>s` used in void context.'
-
METHODS_REPLACEABLE_BY_EACH =
# File 'lib/rubocop/cop/lint/void.rb', line 82%i[collect map].freeze
-
NONMUTATING_METHODS =
# File 'lib/rubocop/cop/lint/void.rb', line 84(NONMUTATING_METHODS_WITH_BANG_VERSION + METHODS_REPLACEABLE_BY_EACH).freeze
-
NONMUTATING_METHODS_WITH_BANG_VERSION =
# File 'lib/rubocop/cop/lint/void.rb', line 75%i[capitalize chomp chop compact delete_prefix delete_suffix downcase encode flatten gsub lstrip merge next reject reverse rotate rstrip scrub select shuffle slice sort sort_by squeeze strip sub succ swapcase tr tr_s transform_values unicode_normalize uniq upcase].freeze
-
NONMUTATING_MSG =
# File 'lib/rubocop/cop/lint/void.rb', line 70'Method `#%<method>s` used in void context. Did you mean `#%<suggest>s`?'
-
OPERATORS =
# File 'lib/rubocop/cop/lint/void.rb', line 74(BINARY_OPERATORS + UNARY_OPERATORS).freeze
-
OP_MSG =
# File 'lib/rubocop/cop/lint/void.rb', line 64'Operator `%<op>s` used in void context.'
-
SELF_MSG =
# File 'lib/rubocop/cop/lint/void.rb', line 68'`self` used in void context.'
-
UNARY_OPERATORS =
# File 'lib/rubocop/cop/lint/void.rb', line 73%i[+@ -@ ~ !].freeze
-
VAR_MSG =
# File 'lib/rubocop/cop/lint/void.rb', line 65'Variable `%<var>s` used in void context.'
::RuboCop::Cop::Base
- Inherited
EMPTY_OFFENSES, RESTRICT_ON_SEND
::RuboCop::Cop::RangeHelp
- Included
Class Attribute Summary
::RuboCop::Cop::AutoCorrector
- Extended
::RuboCop::Cop::Base
- Inherited
.gem_requirements, .lint?, | |
.support_autocorrect? | Returns if class supports autocorrect. |
.support_multiple_source? | Override if your cop should be called repeatedly for multiple investigations Between calls to |
Class Method Summary
::RuboCop::Cop::Base
- Inherited
.autocorrect_incompatible_with | List of cops that should not try to autocorrect at the same time as this cop. |
.badge | Naming. |
.callbacks_needed, .cop_name, .department, | |
.documentation_url | Returns a url to view this cops documentation online. |
.exclude_from_registry | Call for abstract Cop classes. |
.inherited, | |
.joining_forces | Override and return the Force class(es) you need to join. |
.match? | Returns true if the cop name or the cop namespace matches any of the given names. |
.new, | |
.requires_gem | Register a version requirement for the given gem name. |
.restrict_on_send |
::RuboCop::ExcludeLimit
- Extended
exclude_limit | Sets up a configuration option to have an exclude limit tracked. |
transform |
Instance Attribute Summary
::RuboCop::Cop::Base
- Inherited
::RuboCop::Cop::AutocorrectLogic
- Included
Instance Method Summary
- #on_begin(node) (also: #on_kwbegin)
- #on_block(node) (also: #on_numblock, #on_itblock)
- #on_ensure(node)
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#on_itblock(node)
Alias for #on_block.
-
#on_kwbegin(node)
Alias for #on_begin.
-
#on_numblock(node)
Alias for #on_block.
- #all_keys_entirely_literal?(node) ⇒ Boolean private
- #all_values_entirely_literal?(node) ⇒ Boolean private
- #autocorrect_nonmutating_send(corrector, node, suggestion) private
- #autocorrect_void_expression(corrector, node) private
- #autocorrect_void_op(corrector, node) private
- #check_begin(node) private
- #check_ensure(node) private
- #check_expression(expr) private
- #check_literal(node) private
- #check_nonmutating(node) private
- #check_self(node) private
-
#check_var(node)
private
Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity.
- #check_void_expression(node) private
-
#check_void_op(node, &block)
private
Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity.
- #entirely_literal?(node) ⇒ Boolean private
- #in_void_context?(node) ⇒ Boolean private
::RuboCop::Cop::RangeHelp
- Included
#add_range, | |
#arguments_range | A range containing the first to the last argument of a method call or method definition. |
#column_offset_between, | |
#contents_range | A range containing only the contents of a literal with delimiters (e.g. |
#directions, | |
#effective_column | Returns the column attribute of the range, except if the range is on the first line and there’s a byte order mark at the beginning of that line, in which case 1 is subtracted from the column value. |
#final_pos, #move_pos, #move_pos_str, #range_between, #range_by_whole_lines, #range_with_comments, #range_with_comments_and_lines, #range_with_surrounding_comma, #range_with_surrounding_space, #source_range |
::RuboCop::Cop::Base
- Inherited
#add_global_offense | Adds an offense that has no particular location. |
#add_offense | Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense. |
#begin_investigation | Called before any investigation. |
#callbacks_needed, | |
#cop_config | Configuration Helpers. |
#cop_name, #excluded_file?, | |
#external_dependency_checksum | This method should be overridden when a cop’s behavior depends on state that lives outside of these locations: |
#inspect, | |
#message | Gets called if no message is specified when calling |
#name | Alias for Base#cop_name. |
#offenses, | |
#on_investigation_end | Called after all on_… |
#on_new_investigation | Called before all on_… |
#on_other_file | Called instead of all on_… |
#parse | There should be very limited reasons for a Cop to do it’s own parsing. |
#parser_engine, | |
#ready | Called between investigations. |
#relevant_file?, | |
#target_gem_version | Returns a gems locked versions (i.e. |
#target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction, | |
#callback_argument | Reserved for Cop::Cop. |
#complete_investigation | Called to complete an investigation. |
#correct, #current_corrector, | |
#current_offense_locations | Reserved for Commissioner: |
#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range, | |
#reset_investigation | Actually private methods. |
#use_corrector |
::RuboCop::Cop::AutocorrectLogic
- Included
::RuboCop::Cop::IgnoredNode
- Included
Constructor Details
This class inherits a constructor from RuboCop::Cop::Base
Instance Method Details
#all_keys_entirely_literal?(node) ⇒ Boolean
(private)
# File 'lib/rubocop/cop/lint/void.rb', line 269
def all_keys_entirely_literal?(node) node.each_key.all? { |key| entirely_literal?(key) } end
#all_values_entirely_literal?(node) ⇒ Boolean
(private)
# File 'lib/rubocop/cop/lint/void.rb', line 273
def all_values_entirely_literal?(node) node.each_value.all? { |value| entirely_literal?(value) } end
#autocorrect_nonmutating_send(corrector, node, suggestion) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 247
def autocorrect_nonmutating_send(corrector, node, suggestion) send_node = if node.send_type? node else node.send_node end corrector.replace(send_node.loc.selector, suggestion) end
#autocorrect_void_expression(corrector, node) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 240
def autocorrect_void_expression(corrector, node) return if node.parent.if_type? return if (def_node = node.each_ancestor(:any_def).first) && def_node.assignment_method? corrector.remove(range_with_surrounding_space(range: node.source_range, side: :left)) end
#autocorrect_void_op(corrector, node) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 227
def autocorrect_void_op(corrector, node) if node.arguments.empty? corrector.replace(node, node.receiver.source) else corrector.remove(node.loc.dot) if node.loc.dot corrector.replace( range_with_surrounding_space(range: node.loc.selector, side: :both, newlines: false), "\n" ) end end
#check_begin(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 108
def check_begin(node) expressions = *node expressions.pop unless in_void_context?(node) expressions.each do |expr| check_void_op(expr) do block_node = node.each_ancestor(:any_block).first block_node&.method?(:each) end check_expression(expr) end end
#check_ensure(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 212
def check_ensure(node) return unless (body = node.branch) # NOTE: the `begin` node case is already handled via `on_begin` return if body.begin_type? check_expression(body) end
#check_expression(expr) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 122
def check_expression(expr) expr = expr.body if expr.if_type? return unless expr check_literal(expr) check_var(expr) check_self(expr) check_void_expression(expr) return unless cop_config['CheckForMethodsWithNoSideEffects'] check_nonmutating(expr) end
#check_literal(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 170
def check_literal(node) return if !entirely_literal?(node) || node.xstr_type? || node.range_type? add_offense(node, message: format(LIT_MSG, lit: node.source)) do |corrector| autocorrect_void_expression(corrector, node) end end
#check_nonmutating(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 194
def check_nonmutating(node) return unless node.type?(:send, :any_block) method_name = node.method_name return unless NONMUTATING_METHODS.include?(method_name) suggestion = if METHODS_REPLACEABLE_BY_EACH.include?(method_name) 'each' else "#{method_name}!" end add_offense(node, message: format(NONMUTATING_MSG, method: method_name, suggest: suggestion)) do |corrector| autocorrect_nonmutating_send(corrector, node, suggestion) end end
#check_self(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 178
def check_self(node) return unless node.self_type? add_offense(node, message: SELF_MSG) do |corrector| autocorrect_void_expression(corrector, node) end end
#check_var(node) (private)
Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
# File 'lib/rubocop/cop/lint/void.rb', line 152
def check_var(node) return unless node.variable? || node.const_type? if node.const_type? template = node.special_keyword? ? VAR_MSG : CONST_MSG offense_range = node = format(template, var: node.source) else offense_range = node.loc.name = format(VAR_MSG, var: node.loc.name.source) end add_offense(offense_range, message: ) do |corrector| autocorrect_void_expression(corrector, node) end end
#check_void_expression(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 186
def check_void_expression(node) return unless node.defined_type? || node.lambda_or_proc? add_offense(node, message: format(EXPRESSION_MSG, expression: node.source)) do |corrector| autocorrect_void_expression(corrector, node) end end
#check_void_op(node, &block) (private)
Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
# File 'lib/rubocop/cop/lint/void.rb', line 136
def check_void_op(node, &block) node = node.children.first while node&.begin_type? return unless node&.call_type? && OPERATORS.include?(node.method_name) if !UNARY_OPERATORS.include?(node.method_name) && node.loc.dot && node.arguments.none? return end return if block && yield(node) add_offense(node.loc.selector, message: format(OP_MSG, op: node.method_name)) do |corrector| autocorrect_void_op(corrector, node) end end
#entirely_literal?(node) ⇒ Boolean
(private)
# File 'lib/rubocop/cop/lint/void.rb', line 256
def entirely_literal?(node) case node.type when :array all_values_entirely_literal?(node) when :hash all_keys_entirely_literal?(node) && all_values_entirely_literal?(node) when :send, :csend node.method?(:freeze) && node.receiver && entirely_literal?(node.receiver) else node.literal? end end
#in_void_context?(node) ⇒ Boolean
(private)
# File 'lib/rubocop/cop/lint/void.rb', line 220
def in_void_context?(node) parent = node.parent return false unless parent && parent.children.last == node parent.respond_to?(:void_context?) && parent.void_context? end
#on_begin(node) Also known as: #on_kwbegin
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 97
def on_begin(node) check_begin(node) end
#on_block(node) Also known as: #on_numblock, #on_itblock
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 87
def on_block(node) return unless node.body && !node.body.begin_type? return unless in_void_context?(node.body) check_void_op(node.body) { node.method?(:each) } check_expression(node.body) end
#on_ensure(node)
[ GitHub ]# File 'lib/rubocop/cop/lint/void.rb', line 102
def on_ensure(node) check_ensure(node) end
#on_itblock(node)
Alias for #on_block.
# File 'lib/rubocop/cop/lint/void.rb', line 95
alias on_itblock on_block
#on_kwbegin(node)
Alias for #on_begin.
# File 'lib/rubocop/cop/lint/void.rb', line 100
alias on_kwbegin on_begin
#on_numblock(node)
Alias for #on_block.
# File 'lib/rubocop/cop/lint/void.rb', line 94
alias on_numblock on_block