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, #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, 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.loc.expression,
        message: message(method_name, expected_name(method_name.to_s, prefix))
      )
    end
  end
end