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/
redundant_cop_disable_directive.rb
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/
redundant_cop_disable_directive.rb
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# frozen_string_literal: true
# The Lint/RedundantCopDisableDirective cop needs to be disabled so as
# to be able to provide a (bad) example of a redundant disable.
# rubocop:disable Lint/RedundantCopDisableDirective
module RuboCop
module Cop
module Lint
# This cop detects instances of rubocop:disable comments that can be
# removed without causing any offenses to be reported. It's implemented
# as a cop in that it inherits from the Cop base class and calls
# add_offense. The unusual part of its implementation is that it doesn't
# have any on_* methods or an investigate method. This means that it
# doesn't take part in the investigation phase when the other cops do
# their work. Instead, it waits until it's called in a later stage of the
# execution. The reason it can't be implemented as a normal cop is that
# it depends on the results of all other cops to do its work.
#
#
# @example
# # bad
# # rubocop:disable Layout/LineLength
# x += 1
# # rubocop:enable Layout/LineLength
#
# # good
# x += 1
class RedundantCopDisableDirective < Base
include RangeHelp
extend AutoCorrector
COP_NAME = 'Lint/RedundantCopDisableDirective'
attr_accessor :offenses_to_check
def initialize(config = nil, options = nil, offenses = nil)
@offenses_to_check = offenses
super(config, options)
end
def on_new_investigation
return unless offenses_to_check
cop_disabled_line_ranges = processed_source.disabled_line_ranges
redundant_cops = Hash.new { |h, k| h[k] = Set.new }
each_redundant_disable(cop_disabled_line_ranges,
offenses_to_check) do |comment, redundant_cop|
redundant_cops[comment].add(redundant_cop)
end
add_offenses(redundant_cops)
super
end
private
def previous_line_blank?(range)
processed_source.buffer.source_line(range.line - 1).blank?
end
def comment_range_with_surrounding_space(range)
if previous_line_blank?(range)
# When the previous line is blank, it should be retained
range_with_surrounding_space(range: range, side: :right)
else
# Eat the entire comment, the preceding space, and the preceding
# newline if there is one.
original_begin = range.begin_pos
range = range_with_surrounding_space(range: range,
side: :left,
newlines: true)
range_with_surrounding_space(range: range,
side: :right,
# Special for a comment that
# begins the file: remove
# the newline at the end.
newlines: original_begin.zero?)
end
end
def directive_range_in_list(range, ranges)
# Is there any cop between this one and the end of the line, which
# is NOT being removed?
if ends_its_line?(ranges.last) && trailing_range?(ranges, range)
# Eat the comma on the left.
range = range_with_surrounding_space(range: range, side: :left)
range = range_with_surrounding_comma(range, :left)
end
range = range_with_surrounding_comma(range, :right)
# Eat following spaces up to EOL, but not the newline itself.
range_with_surrounding_space(range: range,
side: :right,
newlines: false)
end
def each_redundant_disable(cop_disabled_line_ranges, offenses,
&block)
disabled_ranges = cop_disabled_line_ranges[COP_NAME] || [0..0]
cop_disabled_line_ranges.each do |cop, line_ranges|
each_already_disabled(line_ranges,
disabled_ranges) do |comment|
yield comment, cop
end
each_line_range(line_ranges, disabled_ranges, offenses,
cop, &block)
end
end
def each_line_range(line_ranges, disabled_ranges, offenses,
cop)
line_ranges.each_with_index do |line_range, ix|
comment = processed_source.comment_at_line(line_range.begin)
next if ignore_offense?(disabled_ranges, line_range)
redundant_cop = find_redundant(comment, offenses, cop, line_range,
line_ranges[ix + 1])
yield comment, redundant_cop if redundant_cop
end
end
def each_already_disabled(line_ranges, disabled_ranges)
line_ranges.each_cons(2) do |previous_range, range|
next if ignore_offense?(disabled_ranges, range)
next if previous_range.end != range.begin
# If a cop is disabled in a range that begins on the same line as
# the end of the previous range, it means that the cop was
# already disabled by an earlier comment. So it's redundant
# whether there are offenses or not.
comment = processed_source.comment_at_line(range.begin)
# Comments disabling all cops don't count since it's reasonable
# to disable a few select cops first and then all cops further
# down in the code.
yield comment if comment && !all_disabled?(comment)
end
end
# rubocop:todo Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
def find_redundant(comment, offenses, cop, line_range, next_line_range)
if all_disabled?(comment)
# If there's a disable all comment followed by a comment
# specifically disabling `cop`, we don't report the `all`
# comment. If the disable all comment is truly redundant, we will
# detect that when examining the comments of another cop, and we
# get the full line range for the disable all.
if (next_line_range.nil? ||
line_range.last != next_line_range.first) &&
offenses.none? { |o| line_range.cover?(o.line) }
'all'
end
else
cop_offenses = offenses.select { |o| o.cop_name == cop }
cop if cop_offenses.none? { |o| line_range.cover?(o.line) }
end
end
# rubocop:enable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
def all_disabled?(comment)
/rubocop\s*:\s*(?:disable|todo)\s+all\b/.match?(comment.text)
end
def ignore_offense?(disabled_ranges, line_range)
disabled_ranges.any? do |range|
range.cover?(line_range.min) && range.cover?(line_range.max)
end
end
def directive_count(comment)
match = comment.text.match(CommentConfig::COMMENT_DIRECTIVE_REGEXP)
_, cops_string = match.captures
cops_string.split(/,\s*/).size
end
def add_offenses(redundant_cops)
redundant_cops.each do |comment, cops|
if all_disabled?(comment) ||
directive_count(comment) == cops.size
add_offense_for_entire_comment(comment, cops)
else
add_offense_for_some_cops(comment, cops)
end
end
end
def add_offense_for_entire_comment(comment, cops)
location = comment.loc.expression
cop_list = cops.sort.map { |c| describe(c) }
add_offense(
location,
message: "Unnecessary disabling of #{cop_list.join(', ')}."
) do |corrector|
range = comment_range_with_surrounding_space(location)
corrector.remove(range)
end
end
def add_offense_for_some_cops(comment, cops)
cop_ranges = cops.map { |c| [c, cop_range(comment, c)] }
cop_ranges.sort_by! { |_, r| r.begin_pos }
ranges = cop_ranges.map { |_, r| r }
cop_ranges.each do |cop, range|
add_offense(
range,
message: "Unnecessary disabling of #{describe(cop)}."
) do |corrector|
range = directive_range_in_list(range, ranges)
corrector.remove(range)
end
end
end
def cop_range(comment, cop)
matching_range(comment.loc.expression, cop) ||
matching_range(comment.loc.expression, Badge.parse(cop).cop_name) ||
raise("Couldn't find #{cop} in comment: #{comment.text}")
end
def matching_range(haystack, needle)
offset = haystack.source.index(needle)
return unless offset
offset += haystack.begin_pos
Parser::Source::Range.new(haystack.source_buffer, offset,
offset + needle.size)
end
def trailing_range?(ranges, range)
ranges
.drop_while { |r| !r.equal?(range) }
.each_cons(2)
.map { |range1, range2| range1.end.join(range2.begin).source }
.all? { |intervening| /\A\s*,\s*\Z/.match?(intervening) }
end
def describe(cop)
if cop == 'all'
'all cops'
elsif all_cop_names.include?(cop)
"`#{cop}`"
else
similar = NameSimilarity.find_similar_name(cop, all_cop_names)
if similar
"`#{cop}` (did you mean `#{similar}`?)"
else
"`#{cop}` (unknown cop)"
end
end
end
def all_cop_names
@all_cop_names ||= Registry.global.names
end
def ends_its_line?(range)
line = range.source_buffer.source_line(range.last_line)
(line =~ /\s*\z/) == range.last_column
end
end
end
end
end
# rubocop:enable Lint/RedundantCopDisableDirective