Class: RuboCop::Cop::Naming::PredicateName

Inherits:
Base
  • Object
show all
Includes:
AllowedMethods
Defined in:
lib/rubocop/cop/naming/predicate_name.rb

Overview

Checks that predicate methods names end with a question mark and do not start with a forbidden prefix.

A method is determined to be a predicate method if its name starts with one of the prefixes defined in the NamePrefix configuration. You can change what prefixes are considered by changing this option. Any method name that starts with one of these prefixes is required by the cop to end with a ?. Other methods can be allowed by adding to the AllowedMethods configuration.

Note
 The is_a? method is allowed by default.

If ForbiddenPrefixes is set, methods that start with the configured prefixes will not be allowed and will be removed by autocorrection.

In other words, if ForbiddenPrefixes is empty, a method named is_foo will register an offense only due to the lack of question mark (and will be autocorrected to is_foo?). If ForbiddenPrefixes contains is_, is_foo will register an offense both because the ? is missing and because of the is_ prefix, and will be corrected to foo?.

Note
 ForbiddenPrefixes is only applied to prefixes in NamePrefix; a prefix in the former but not the latter will not be considered by this cop.

Examples:

# bad
def is_even(value)
end

def is_even?(value)
end

# good
def even?(value)
end

# bad
def has_value
end

def has_value?
end

# good
def value?
end

AllowedMethods: ['is_a?'] (default)

# good
def is_a?(value)
end

Constant Summary

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #begin_investigation, callbacks_needed, #callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

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

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#dynamic_method_define(node) ⇒ Object 



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# File 'lib/rubocop/cop/naming/predicate_name.rb', line 63

def_node_matcher :dynamic_method_define, <<~PATTERN
  (send nil? #method_definition_macros
    (sym $_)
    ...)
PATTERN

#on_def(node) ⇒ Object Also known as: on_defs 



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# File 'lib/rubocop/cop/naming/predicate_name.rb', line 82

def on_def(node)
  predicate_prefixes.each do |prefix|
    method_name = node.method_name.to_s

    next if allowed_method_name?(method_name, prefix)

    add_offense(
      node.loc.name,
      message: message(method_name, expected_name(method_name, prefix))
    )
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/naming/predicate_name.rb', line 69

def on_send(node)
  dynamic_method_define(node) do |method_name|
    predicate_prefixes.each do |prefix|
      next if allowed_method_name?(method_name.to_s, prefix)

      add_offense(
        node.first_argument.source_range,
        message: message(method_name, expected_name(method_name.to_s, prefix))
      )
    end
  end
end