Class: RuboCop::Cop::Style::MapIntoArray
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
|
|
Instance Chain:
self,
::RuboCop::Cop::RangeHelp ,
::RuboCop::Cop::Base ,
::RuboCop::Cop::AutocorrectLogic ,
::RuboCop::Cop::IgnoredNode ,
::RuboCop::Util ,
RuboCop::AST::Sexp
|
|
Inherits: |
RuboCop::Cop::Base
|
Defined in: | lib/rubocop/cop/style/map_into_array.rb |
Overview
Checks for usages of each
with <<
, push
, or append
which
can be replaced by map
.
If PreferredMethods
is configured for map
in Style/CollectionMethods
,
this cop uses the specified method for replacement.
Note
|
The return value of Enumerable#each is self , whereas the
return value of Enumerable#map is an Array . They are not autocorrected
when a return value could be used because these types differ.
|
Note
|
It only detects when the mapping destination is either:
* a local variable initialized as an empty array and referred to only by the
pushing operation;
* or, if it is the single block argument to a [].tap block.
This is because, if not, it’s challenging to statically guarantee that the
mapping destination variable remains an empty array:
|
ret = []
src.each { |e| ret << e * 2 } # {<<} method may mutate {ret}
dest = []
src.each { |e| dest << transform(e, dest) } # {transform} method may mutate {dest}
Constant Summary
-
MSG =
# File 'lib/rubocop/cop/style/map_into_array.rb', line 64'Use `%<new_method_name>s` instead of `each` to map elements into an array.'
::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
- #after_leaving_scope(scope, _variable_table)
- #each_block_with_push?(node)
- #empty_array_asgn?(node)
- #empty_array_tap(node)
- #lvar_ref?(node, name)
- #on_block(node) (also: #on_numblock)
-
#on_numblock(node)
Alias for #on_block.
- #suitable_argument_node?(node)
- #correct_push_node(corrector, push_node) private
- #correct_return_value_handling(corrector, block, dest_var) private
- #dest_used_only_for_mapping?(block, dest_var, asgn) ⇒ Boolean private
- #find_closest_assignment(block, dest_var) private
- #find_dest_var(block) private
- #new_method_name private
- #offending_empty_array_tap?(node, dest_var) ⇒ Boolean private
- #register_offense(block, dest_var, asgn) private
- #remove_assignment(corrector, asgn) private
- #remove_tap(corrector, node, block_node) private
- #return_value_used?(node) ⇒ Boolean private
::RuboCop::Cop::RangeHelp
- Included
#add_range, #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_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
#disable_offense, #disable_offense_at_end_of_line, #disable_offense_before_and_after, #disable_offense_with_eol_or_surround_comment, #heredoc_range, #max_line_length, #multiline_ranges, #multiline_string?, | |
#range_by_lines | Expand the given range to include all of any lines it covers. |
#range_of_first_line, #range_overlaps_offense?, #string_continuation?, #surrounding_heredoc?, #surrounding_percent_array? |
::RuboCop::Cop::IgnoredNode
- Included
Constructor Details
This class inherits a constructor from RuboCop::Cop::Base
Class Method Details
.joining_forces
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 105
def self.joining_forces VariableForce end
Instance Method Details
#after_leaving_scope(scope, _variable_table)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 109
def after_leaving_scope(scope, _variable_table) (@scopes ||= []) << scope end
#correct_push_node(corrector, push_node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 213
def correct_push_node(corrector, push_node) range = push_node.source_range arg_range = push_node.first_argument.source_range corrector.remove(range_between(range.begin_pos, arg_range.begin_pos)) corrector.remove(range_between(arg_range.end_pos, range.end_pos)) end
#correct_return_value_handling(corrector, block, dest_var) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 221
def correct_return_value_handling(corrector, block, dest_var) next_node = block.right_sibling if lvar_ref?(next_node, dest_var.name) corrector.remove(range_with_surrounding_space(next_node.source_range, side: :left)) end corrector.insert_before(block, "#{dest_var.name} = ") end
#dest_used_only_for_mapping?(block, dest_var, asgn) ⇒ Boolean
(private)
# File 'lib/rubocop/cop/style/map_into_array.rb', line 156
def dest_used_only_for_mapping?(block, dest_var, asgn) range = asgn.source_range.join(block.source_range) asgn.parent.equal?(block.parent) && dest_var.references.one? { |r| range.contains?(r.node.source_range) } && dest_var.assignments.one? { |a| range.contains?(a.node.source_range) } end
#each_block_with_push?(node)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 72
def_node_matcher :each_block_with_push?, <<-PATTERN [ ^({begin kwbegin block} ...) ({block numblock} (send !{nil? self} :each) _ (send (lvar _) {:<< :push :append} #suitable_argument_node?)) ] PATTERN
#empty_array_asgn?(node)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 81
def_node_matcher :empty_array_asgn?, <<~PATTERN ( lvasgn _ { (array) (send (const {nil? cbase} :Array) :[]) (send (const {nil? cbase} :Array) :new (array)?) (send nil? :Array (array)) } ) PATTERN
#empty_array_tap(node)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 93
def_node_matcher :empty_array_tap, <<~PATTERN ^^$( block (send (array) :tap) (args (arg _)) ... ) PATTERN
#find_closest_assignment(block, dest_var) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 150
def find_closest_assignment(block, dest_var) dest_var.assignments.reverse_each.lazy.map(&:node).find do |node| node.source_range.end_pos < block.source_range.begin_pos end end
#find_dest_var(block) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 133
def find_dest_var(block) node = block.body.receiver name = node.children.first candidates = @scopes.lazy.filter_map { |s| s.variables[name] } candidates.find { |v| v.references.any? { |n| n.node.equal?(node) } } end
#lvar_ref?(node, name)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 103
def_node_matcher :lvar_ref?, '(lvar %1)'
#new_method_name (private)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 181
def new_method_name default = 'map' alternative = config.for_cop('Style/CollectionMethods').dig('PreferredMethods', default) alternative || default end
#offending_empty_array_tap?(node, dest_var) ⇒ Boolean
(private)
# File 'lib/rubocop/cop/style/map_into_array.rb', line 141
def offending_empty_array_tap?(node, dest_var) return false unless (tap_block_node = empty_array_tap(dest_var.declaration_node)) # A `tap` block only offends if the array push is the only thing in it; # otherwise we cannot guarantee that the block variable is still an empty # array when pushed to. tap_block_node.body == node end
#on_block(node) Also known as: #on_numblock
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 113
def on_block(node) return unless each_block_with_push?(node) dest_var = find_dest_var(node) if offending_empty_array_tap?(node, dest_var) asgn = dest_var.declaration_node else return unless (asgn = find_closest_assignment(node, dest_var)) return unless empty_array_asgn?(asgn) return unless dest_used_only_for_mapping?(node, dest_var, asgn) end register_offense(node, dest_var, asgn) end
#on_numblock(node)
Alias for #on_block.
# File 'lib/rubocop/cop/style/map_into_array.rb', line 129
alias on_numblock on_block
#register_offense(block, dest_var, asgn) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 164
def register_offense(block, dest_var, asgn) add_offense(block, message: format(MSG, new_method_name: new_method_name)) do |corrector| next if return_value_used?(block) corrector.replace(block.send_node.selector, new_method_name) if (tap_block_node = empty_array_tap(dest_var.declaration_node)) remove_tap(corrector, block, tap_block_node) else remove_assignment(corrector, asgn) end correct_push_node(corrector, block.body) correct_return_value_handling(corrector, block, dest_var) end end
#remove_assignment(corrector, asgn) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 200
def remove_assignment(corrector, asgn) range = range_with_surrounding_space(asgn.source_range, side: :right) range = range_with_surrounding_space(range, side: :right, newlines: false) corrector.remove(range) end
#remove_tap(corrector, node, block_node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 207
def remove_tap(corrector, node, block_node) range = range_between(block_node.source_range.begin_pos, node.source_range.begin_pos) corrector.remove(range) corrector.remove(range_with_surrounding_space(block_node.loc.end, side: :left)) end
#return_value_used?(node) ⇒ Boolean
(private)
# File 'lib/rubocop/cop/style/map_into_array.rb', line 187
def return_value_used?(node) parent = node.parent case parent&.type when nil false when :begin, :kwbegin !node.right_sibling && return_value_used?(parent) else !parent.respond_to?(:void_context?) || !parent.void_context? end end
#suitable_argument_node?(node)
[ GitHub ]# File 'lib/rubocop/cop/style/map_into_array.rb', line 67
def_node_matcher :suitable_argument_node?, <<-PATTERN !{splat forwarded-restarg forwarded-args (hash (forwarded-kwrestarg)) (block-pass nil?)} PATTERN