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Class: RuboCop::Cop::Lint::SymbolConversion

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/symbol_conversion.rb

Overview

Checks for uses of literal strings converted to a symbol where a literal symbol could be used instead.

There are two possible styles for this cop. strict (default) will register an offense for any incorrect usage. consistent additionally requires hashes to use the same style for every symbol key (ie. if any symbol key needs to be quoted it requires all keys to be quoted).

Examples:

# bad
'string'.to_sym
:symbol.to_sym
'underscored_string'.to_sym
:'underscored_symbol'
'hyphenated-string'.to_sym
"string_#{interpolation}".to_sym

# good
:string
:symbol
:underscored_string
:underscored_symbol
:'hyphenated-string'
:"string_#{interpolation}"

EnforcedStyle: strict (default)

# bad
{
  'a': 1,
  "b": 2,
  'c-d': 3
}

# good (don't quote keys that don't require quoting)
{
  a: 1,
  b: 2,
  'c-d': 3
}

EnforcedStyle: consistent

# bad
{
  a: 1,
  'b-c': 2
}

# good (quote all keys if any need quoting)
{
  'a': 1,
  'b-c': 2
}

# good (no quoting required)
{
  a: 1,
  b: 2
}

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

SYMBOL_TO_STRING_CACHE

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 an 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::SymbolHelp - Included

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

::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_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

#correct_hash_key(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 147

def correct_hash_key(node)
  # Although some operators can be converted to symbols normally
  # (ie. `:==`), these are not accepted as hash keys and will
  # raise a syntax error (eg. `{ ==: ... }`). Therefore, if the
  # symbol does not start with an alphanumeric or underscore, it
  # will be ignored.
  return unless node.value.to_s.match?(/\A[a-z0-9_]/i)

  correction = node.value.inspect
  correction = correction.delete_prefix(':') if node.parent.colon?
  return if properly_quoted?(node.source, correction)

  register_offense(
    node,
    correction: correction,
    message: format(MSG, correction: node.parent.colon? ? "#{correction}:" : correction)
  )
end

#correct_inconsistent_hash_keys(keys) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 166

def correct_inconsistent_hash_keys(keys)
  keys.each do |key|
    ignore_node(key)

    next if requires_quotes?(key)
    next if properly_quoted?(key.source, %("#{key.value}"))

    correction = %("#{key.value}")
    register_offense(
      key,
      correction: correction,
      message: format(MSG_CONSISTENCY, correction: "#{correction}:")
    )
  end
end

#in_alias?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 139

def in_alias?(node)
  node.parent&.alias_type?
end

#in_percent_literal_array?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 143

def in_percent_literal_array?(node)
  node.parent&.array_type? && node.parent&.percent_literal?
end

#on_hash(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 105

def on_hash(node)
  # For `EnforcedStyle: strict`, hash keys are evaluated in `on_sym`
  return unless style == :consistent

  keys = node.keys.select(&:sym_type?)

  if keys.any? { |key| requires_quotes?(key) }
    correct_inconsistent_hash_keys(keys)
  else
    # If there are no symbol keys requiring quoting,
    # treat the hash like `EnforcedStyle: strict`.
    keys.each { |key| correct_hash_key(key) }
  end
end

#on_send(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 78

def on_send(node)
  return unless node.receiver

  if node.receiver.str_type? || node.receiver.sym_type?
    register_offense(node, correction: node.receiver.value.to_sym.inspect)
  elsif node.receiver.dstr_type?
    register_offense(node, correction: ":\"#{node.receiver.value.to_sym}\"")
  end
end

#on_sym(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 88

def on_sym(node)
  return if ignored_node?(node) || properly_quoted?(node.source, node.value.inspect)

  # `alias` arguments are symbols but since a symbol that requires
  # being quoted is not a valid method identifier, it can be ignored
  return if in_alias?(node)

  # The `%I[]` and `%i[]` macros are parsed as normal arrays of symbols
  # so they need to be ignored.
  return if in_percent_literal_array?(node)

  # Symbol hash keys have a different format and need to be handled separately
  return correct_hash_key(node) if hash_key?(node)

  register_offense(node, correction: node.value.inspect)
end

#properly_quoted?(source, value) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 126

def properly_quoted?(source, value)
  return true if style == :strict && (!source.match?(/['"]/) || value.end_with?('='))

  source == value ||
    # `Symbol#inspect` uses double quotes, but allow single-quoted
    # symbols to work as well.
    source.gsub('"', '\"').tr("'", '"') == value
end

#register_offense(node, correction:, message: format(MSG, correction: correction)) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 122

def register_offense(node, correction:, message: format(MSG, correction: correction))
  add_offense(node, message: message) { |corrector| corrector.replace(node, correction) }
end

#requires_quotes?(sym_node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/symbol_conversion.rb', line 135

def requires_quotes?(sym_node)
  sym_node.value.inspect.match?(/^:".*?"|=$/)
end