Class: RuboCop::Cop::Lint::InheritException

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
ConfigurableEnforcedStyle, ProjectIndexHelp
Defined in:
lib/rubocop/cop/lint/inherit_exception.rb

Overview

Looks for error classes inheriting from Exception. It is configurable to suggest using either StandardError (default) or RuntimeError instead.

When AllCops/UseProjectIndex is enabled and the rubydex gem is installed, indirect inheritance is also detected: a class whose parent (defined anywhere in the project) ultimately inherits from Exception is reported, without autocorrection.

Examples:

EnforcedStyle: standard_error (default)

# bad

class C < Exception; end

C = Class.new(Exception)

# good

class C < StandardError; end

C = Class.new(StandardError)

EnforcedStyle: runtime_error

# bad

class C < Exception; end

C = Class.new(Exception)

# good

class C < RuntimeError; end

C = Class.new(RuntimeError)

Constant Summary collapse

MSG = 
'Inherit from `%<prefer>s` instead of `Exception`.'
INDIRECT_MSG = 
'Inherit from `%<prefer>s` instead of `Exception` (inherited via `%<via>s`).'
PREFERRED_BASE_CLASS = 
{
  runtime_error: 'RuntimeError',
  standard_error: 'StandardError'
}.freeze
RESTRICT_ON_SEND = 
%i[new].freeze

Constants included from ProjectIndexHelp

ProjectIndexHelp::BUILTIN_DOCUMENT_URI, ProjectIndexHelp::FILE_URI_PREFIX, ProjectIndexHelp::WINDOWS_DRIVE_PREFIX

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source, #project_index

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods included from ProjectIndexHelp

#external_dependency_checksum

Methods included from ConfigurableEnforcedStyle

#alternative_style, #alternative_styles, #ambiguous_style_detected, #correct_style_detected, #detected_style, #detected_style=, #no_acceptable_style!, #no_acceptable_style?, #opposite_style_detected, #style, #style_configured?, #style_detected, #style_parameter_name, #supported_styles, #unexpected_style_detected

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #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, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_gem_version, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

cop_dir_for, #exclude_limit, read_limits

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

#class_new_call?(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/inherit_exception.rb', line 60

def_node_matcher :class_new_call?, <<~PATTERN
  (send
    (const {cbase nil?} :Class) :new
    $(const {cbase nil?} _))
PATTERN

#on_class(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/inherit_exception.rb', line 66

def on_class(node)
  parent_class = node.parent_class
  return unless parent_class

  if exception_class?(parent_class)
    return if inherit_exception_class_with_omitted_namespace?(node)

    add_offense(parent_class, message: message(parent_class)) do |corrector|
      corrector.replace(parent_class, preferred_base_class)
    end
  elsif (via = inherits_exception_via(parent_class))
    # No autocorrection: the `Exception` inheritance lives at another
    # class' definition site, possibly in another file.
    message = format(INDIRECT_MSG, prefer: preferred_base_class, via: via)
    add_offense(parent_class, message: message)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/inherit_exception.rb', line 84

def on_send(node)
  constant = class_new_call?(node)
  return unless constant && exception_class?(constant)

  message = message(constant)

  add_offense(constant, message: message) do |corrector|
    corrector.replace(constant, preferred_base_class)
  end
end