Class: RuboCop::Cop::Style::SignalException

Inherits:
Cop
  • Object
show all
Includes:
ConfigurableEnforcedStyle
Defined in:
lib/rubocop/cop/style/signal_exception.rb

Overview

This cop checks for uses of ‘fail` and `raise`.

Examples:

EnforcedStyle: only_raise (default)

# The `only_raise` style enforces the sole use of `raise`.
# bad
begin
  fail
rescue Exception
  # handle it
end

def watch_out
  fail
rescue Exception
  # handle it
end

Kernel.fail

# good
begin
  raise
rescue Exception
  # handle it
end

def watch_out
  raise
rescue Exception
  # handle it
end

Kernel.raise

EnforcedStyle: only_fail

# The `only_fail` style enforces the sole use of `fail`.
# bad
begin
  raise
rescue Exception
  # handle it
end

def watch_out
  raise
rescue Exception
  # handle it
end

Kernel.raise

# good
begin
  fail
rescue Exception
  # handle it
end

def watch_out
  fail
rescue Exception
  # handle it
end

Kernel.fail

EnforcedStyle: semantic

# The `semantic` style enforces the use of `fail` to signal an
# exception, then will use `raise` to trigger an offense after
# it has been rescued.
# bad
begin
  raise
rescue Exception
  # handle it
end

def watch_out
  # Error thrown
rescue Exception
  fail
end

Kernel.fail
Kernel.raise

# good
begin
  fail
rescue Exception
  # handle it
end

def watch_out
  fail
rescue Exception
  raise 'Preferably with descriptive message'
end

explicit_receiver.fail
explicit_receiver.raise

Constant Summary collapse

FAIL_MSG = 
'Use `fail` instead of `raise` to signal exceptions.'.freeze
RAISE_MSG = 
'Use `raise` instead of `fail` to ' \
'rethrow exceptions.'.freeze

Constants included from Util

Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

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_detected, #style_parameter_name, #supported_styles, #unexpected_style_detected

Methods inherited from Cop

#add_offense, all, autocorrect_incompatible_with, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #messages, non_rails, #parse, qualified_cop_name, #relevant_file?, #target_rails_version, #target_ruby_version

Methods included from AST::Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, comment_line?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, operator?, parentheses?, parenthesized_call?, precede?, range_between, range_by_whole_lines, range_with_surrounding_comma, range_with_surrounding_space, same_line?, source_range, strip_quotes, stripped_source_upto, symbol_without_quote?, to_string_literal, to_supported_styles, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, find_file_upwards, match_path?, pwd, relative_path, reset_pwd, smart_path

Constructor Details

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

Instance Method Details

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/signal_exception.rb', line 147

def autocorrect(node)
  lambda do |corrector|
    name =
      case style
      when :semantic
        command_or_kernel_call?(:raise, node) ? 'fail' : 'raise'
      when :only_raise then 'raise'
      when :only_fail then 'fail'
      end

    corrector.replace(node.loc.selector, name)
  end
end

#investigate(processed_source) ⇒ Object 



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# File 'lib/rubocop/cop/style/signal_exception.rb', line 118

def investigate(processed_source)
  ast = processed_source.ast
  @custom_fail_defined = ast && custom_fail_methods(ast).any?
end

#on_rescue(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/signal_exception.rb', line 123

def on_rescue(node)
  return unless style == :semantic

  begin_node, *rescue_nodes, _else_node = *node
  check_scope(:raise, begin_node)

  rescue_nodes.each do |rescue_node|
    check_scope(:fail, rescue_node)
    allow(:raise, rescue_node)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/signal_exception.rb', line 135

def on_send(node)
  case style
  when :semantic
    check_send(:raise, node) unless ignored_node?(node)
  when :only_raise
    return if @custom_fail_defined
    check_send(:fail, node)
  when :only_fail
    check_send(:raise, node)
  end
end