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Class: RuboCop::Cop::Lint::RaiseException

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:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/lint/raise_exception.rb

Overview

Checks for raise or fail statements which raise Exception or Exception.new. Use StandardError or a specific exception class instead.

If you have defined your own namespaced Exception class, it is possible to configure the cop to allow it by setting AllowedImplicitNamespaces to an array with the names of the namespaces to allow. By default, this is set to ['Gem'], which allows Gem::Exception to be raised without an explicit namespace. If not allowed, a false positive may be registered if raise Exception is called within the namespace.

Alternatively, use a fully qualified name with raise/fail (eg. raise Namespace::Exception).

Examples:

# bad
raise Exception, 'Error message here'
raise Exception.new('Error message here')

# good
raise StandardError, 'Error message here'
raise MyError.new, 'Error message here'

AllowedImplicitNamespaces: ['Gem'] (default)

# bad - {Foo} is not an allowed implicit namespace
module Foo
  def self.foo
    raise Exception # This is qualified to {Foo::Exception}.
  end
end

# good
module Gem
  def self.foo
    raise Exception # This is qualified to {Gem::Exception}.
  end
end

# good
module Foo
  def self.foo
    raise Foo::Exception
  end
end

Cop Safety Information:

  • This cop is unsafe because it will change the exception class being raised, which is a change in behavior.

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

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 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

::RuboCop::ExcludeLimit - Extended

exclude_limit

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

transform

Instance Attribute Summary

Instance Method Summary

::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 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, #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

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

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

Instance Method Details

#allow_implicit_namespaces (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/raise_exception.rb', line 104

def allow_implicit_namespaces
  cop_config['AllowedImplicitNamespaces'] || []
end

#check(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/raise_exception.rb', line 76

def check(node)
  lambda do |exception_class, cbase|
    return if cbase.nil? && implicit_namespace?(node)

    add_offense(exception_class) do |corrector|
      prefer_exception = if exception_class.children.first&.cbase_type?
                           '::StandardError'
                         else
                           'StandardError'
                         end

      corrector.replace(exception_class, prefer_exception)
    end
  end
end

#exception?(node)

[ GitHub ]

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

def_node_matcher :exception?, <<~PATTERN
  (send nil? {:raise :fail} $(const ${cbase nil?} :Exception) ... )
PATTERN

#exception_new_with_message?(node)

[ GitHub ]

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

def_node_matcher :exception_new_with_message?, <<~PATTERN
  (send nil? {:raise :fail}
    (send $(const ${cbase nil?} :Exception) :new ... ))
PATTERN

#implicit_namespace?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/raise_exception.rb', line 92

def implicit_namespace?(node)
  return false unless (parent = node.parent)

  if parent.module_type?
    namespace = parent.identifier.source

    return allow_implicit_namespaces.include?(namespace)
  end

  implicit_namespace?(parent)
end

#on_send(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/raise_exception.rb', line 70

def on_send(node)
  exception?(node, &check(node)) || exception_new_with_message?(node, &check(node))
end