Class: RuboCop::Cop::Lint::MisplacedMagicComment

Inherits:

Base

• Object
• Base
• RuboCop::Cop::Lint::MisplacedMagicComment

Extended by:

AutoCorrector

Includes:

RangeHelp

Defined in:

lib/rubocop/cop/lint/misplaced_magic_comment.rb

Overview

Checks for magic comments placed where Ruby silently ignores them.

The encoding magic comment is only honored on the first line of a file, or on the second line when the first line is a shebang. Anywhere else it is silently ignored - even directly below another comment or a blank line.

Other magic comments (such as frozen_string_literal) are honored anywhere before the first token of code, but are ignored after any code, with a warning emitted only when running Ruby with -w.

A magic comment misplaced ahead of a shebang also renders the shebang ineffective, since a shebang is only recognized on the first line.

NOTE: An encoding comment that is only preceded by other magic comments is not flagged by this cop; that case is handled by Lint/OrderedMagicComments. shareable_constant_value is never flagged, as Ruby intentionally allows it mid-file with block scoping.

Examples:

# bad
# Documentation comment
# encoding: ascii-8bit
puts 'hello'

# good
# encoding: ascii-8bit
# Documentation comment
puts 'hello'

# bad
require 'foo'
# frozen_string_literal: true

# good
# frozen_string_literal: true
require 'foo'

# bad
# frozen_string_literal: true
#!/usr/bin/env ruby
puts 'hello'

# good
#!/usr/bin/env ruby
# frozen_string_literal: true
puts 'hello'

Constant Summary

MSG_ENCODING =

'The `encoding` magic comment is ignored unless placed on the first ' \
'line (or below a shebang on the first line).'

MSG_AFTER_CODE =

'The `%<directive>s` magic comment is ignored after any code.'

MSG_ABOVE_SHEBANG =

'A magic comment above a shebang renders the shebang ineffective.'

Constants included from RangeHelp

RangeHelp::BYTE_ORDER_MARK, RangeHelp::NOT_GIVEN

Constants inherited from Base

Base::DEPARTMENT_SEVERITIES, Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source, #project_index

Instance Method Summary

• #on_new_investigation ⇒ Object

Methods included from AutoCorrector

support_autocorrect?

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?, #message, #offenses, #on_investigation_end, #on_other_file, #parse, #parser_engine, #preview?, #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?, #skipped_unsafe_correction_with_disable_uncorrectable?

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

#on_new_investigation ⇒ Object

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

def on_new_investigation
  return if processed_source.buffer.source.empty?

  check_magic_comment_above_shebang
  processed_source.comments.each { |comment| check_comment(comment) }
end