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Class: RuboCop::Cop::Lint::ArgumentMismatch

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
self, ::RuboCop::Cop::IndexedMethodArity, ::RuboCop::Cop::ProjectIndexHelp, ::RuboCop::Cop::Base, ::RuboCop::Cop::AutocorrectLogic, ::RuboCop::Cop::IgnoredNode, ::RuboCop::Util, RuboCop::AST::Sexp
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/lint/argument_mismatch.rb

Overview

Checks for calls that pass the wrong number of positional arguments to a method whose definition is known from the project index.

The check is powered by the project-wide index, so it only runs when AllCops/UseProjectIndex is enabled and the rubydex gem is installed. Without the index the cop does nothing.

Only calls on constant receivers (Foo.bar) are considered, and only when the receiver resolves in the index, its entire ancestry is resolved (so a method inherited from a gem or the standard library never produces an offense), and the called method resolves to a single, unambiguous signature. Calls that forward arguments (, *, …​) are skipped because their argument count is not statically known. Keyword arguments passed to a method that declares no keyword parameters are counted as the single positional hash they collapse into, matching Ruby’s semantics.

Constructor calls (Foo.new) and keyword-argument validation are out of scope: only positional arity of explicitly defined singleton methods is checked. new is skipped outright, because Class#new is not in the index: any new the index does find sits below it in the method resolution order, where Ruby would never reach it.

Examples:

# Given the project defines:
#   class Report
#     def self.generate(source, format); end
#   end

# bad
Report.generate(source)

# bad
Report.generate(source, :pdf, :extra)

# good
Report.generate(source, :pdf)

Constant Summary

::RuboCop::Cop::Base - Inherited

DEPARTMENT_SEVERITIES, EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::ProjectIndexHelp - Included

BUILTIN_DOCUMENT_URI, FILE_URI_PREFIX, WINDOWS_DRIVE_PREFIX

Class Attribute Summary

::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 on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

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

Reserved for Commissioner.

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.
transform

Instance Attribute Summary

::RuboCop::Cop::Base - Inherited

#active_support_extensions_enabled?, #always_autocorrect?, #config, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?,
#preview?

Whether the user opted in to unstable behavior, with --preview or AllCops: Preview.
#processed_source, #project_index, #string_literals_frozen_by_default?, #target_satisfies_all_gem_version_requirements?

::RuboCop::Cop::AutocorrectLogic - Included

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?,
#skipped_unsafe_correction_with_disable_uncorrectable?

Whether a correction exists but is skipped because it is unsafe in a safe autocorrect run, while --disable-uncorrectable asks for a todo comment on everything this run cannot correct.

Instance Method Summary

::RuboCop::Cop::IndexedMethodArity - Included

#arity_satisfied?, #double_splat?, #expected_range, #forwards_arguments?,
#indexed_member_shape

The agreed [min, max, has_keywords] shape of an indexed member’s method definitions, or nil when the member is not backed by plain method definitions (attr, alias), has no signature, forwards arguments, or its definitions disagree on arity (e.g.
#keyword_hash, #keyword_parameters?, #maximum_positional,
#positional_argument_count

The number of positional arguments the call passes, or nil when it cannot be determined statically (argument forwarding).
#shape_for, #signature_shape

::RuboCop::Cop::ProjectIndexHelp - Included

#external_dependency_checksum, #compute_project_index_signature,
#definitions_in_other_files

Returns the definitions among definitions that live in a file other than the one being inspected, ordered by path and line.
#fully_resolved_index_ancestry?

Whether every link of the declaration’s ancestry is resolved in the index: no definition of any ancestor has an unresolved superclass or mixin reference.
#indexed_singleton_member

A namespace without any singleton method has no singleton-class declaration of its own, so the lookup starts from the first ancestor that has one; its find_member covers the rest of the chain.
#indexed_singleton_of

The declaration of `declaration’s singleton class, or nil when no singleton method is defined on it anywhere in the project.
#inherited_index_member?

Whether an ancestor of scope other than scope itself defines member_name.
#lexical_nesting_of

The lexical nesting the node’s constants resolve through, outermost first.
#prior_definition_in_other_file, #project_index_signature,
#resolve_constant_in_index

Resolves a constant node the way Ruby does: the first segment through the lexical nesting and every following segment inside the previous one.
#resolved_mixin_references?, #resolved_superclass_reference?, #same_file?

::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

 — grouped under the Commissioner heading above.
#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 add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.
#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, #covering_disabled_range, #current_corrector,
#current_offense_locations

Reserved for Commissioner:
#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?,
#enabled_lines?

A multi-line offense is suppressed by a directive on any line of its range, not only its first line, matching the intuition that the directive is attached to the offending code.
#file_name_matches_any?, #find_message, #find_severity, #matches_absolute_include_pattern?, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.
#suppression_reason

The -- reason on the directive that suppresses offenses on this range, or nil when the directive carries none.
#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, #eol_comment, #eol_comment_would_be_inside_literal?, #heredoc_range, #line_with_eol_comment_too_long?, #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, #string_continuation?, #surrounding_heredoc?, #surrounding_percent_array?

::RuboCop::Cop::IgnoredNode - Included

#ignore_node, #ignored_node?, #part_of_ignored_node?, #ignored_nodes

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#checkable_call?(node) ⇒ Boolean (private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/lint/argument_mismatch.rb', line 65



def checkable_call?(node)
  project_index && node.receiver&.const_type? && !node.method?(:new)
end


  








  

    #message(node, given, min, max)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/argument_mismatch.rb', line 69



def message(node, given, min, max)
  format(MSG, method: node.method_name, given: given, expected: expected_range(min, max))
end


  








  

    #on_csend(node)  
  



  

    


Alias for #on_send.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/argument_mismatch.rb', line 61



alias on_csend on_send


  








  

    #on_send(node)  
    Also known as: #on_csend
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/argument_mismatch.rb', line 49



def on_send(node)
  return unless checkable_call?(node)

  shape = resolved_signature_shape(node)
  return unless shape

  min, max, has_keywords = shape
  given = positional_argument_count(node, has_keywords)
  return if given.nil? || arity_satisfied?(given, min, max)

  add_offense(node.loc.selector, message: message(node, given, min, max))
end


  








  

    #resolved_signature_shape(node)   (private)
  



  

    


[min, max, has_keywords] for the called singleton method, or nil when
the receiver or its ancestry is not resolved.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/argument_mismatch.rb', line 75



def resolved_signature_shape(node)
  declaration = resolve_constant_in_index(node.receiver)
  return nil unless declaration.is_a?(Rubydex::Namespace)
  return nil unless fully_resolved_index_ancestry?(declaration)

  singleton_signature_shape(declaration, node.method_name)
rescue StandardError
  nil
end


  








  

    #singleton_signature_shape(declaration, method_name)   (private)
  



  

    


A call with an explicit receiver cannot reach a private method, so its
signature says nothing about the call. This matters because Object
closes the singleton ancestry of every constant, and a bare def at
the top level of any file — what every block-based DSL produces — is a
private instance method of Object.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/argument_mismatch.rb', line 90



def singleton_signature_shape(declaration, method_name)
  member = indexed_singleton_member(declaration, "#{method_name}()")
  return nil unless member&.public?

  indexed_member_shape(member)
end