lib/rubocop/cop/layout/trailing_whitespace.rb
# frozen_string_literal: true
module RuboCop
module Cop
module Layout
# Looks for trailing whitespace in the source code.
#
# @example
# # The line in this example contains spaces after the 0.
# # bad
# x = 0
#
# # The line in this example ends directly after the 0.
# # good
# x = 0
#
# @example AllowInHeredoc: false (default)
# # The line in this example contains spaces after the 0.
# # bad
# code = <<~RUBY
# x = 0
# RUBY
#
# # ok
# code = <<~RUBY
# x = 0 #{}
# RUBY
#
# # good
# trailing_whitespace = ' '
# code = <<~RUBY
# x = 0#{trailing_whitespace}
# RUBY
#
# @example AllowInHeredoc: true
# # The line in this example contains spaces after the 0.
# # good
# code = <<~RUBY
# x = 0
# RUBY
#
class TrailingWhitespace < Base
include RangeHelp
include Heredoc
extend AutoCorrector
MSG = 'Trailing whitespace detected.'
def on_new_investigation
processed_source.lines.each_with_index do |line, index|
next unless line.end_with?(' ', "\t")
process_line(line, index + 1)
end
end
def on_heredoc(_node); end
private
def process_line(line, lineno)
heredoc = find_heredoc(lineno)
return if skip_heredoc? && heredoc
range = offense_range(lineno, line)
add_offense(range) do |corrector|
if heredoc
process_line_in_heredoc(corrector, range, heredoc)
else
corrector.remove(range)
end
end
end
def process_line_in_heredoc(corrector, range, heredoc)
indent_level = indent_level(find_heredoc(range.line).loc.heredoc_body.source)
whitespace_only = whitespace_only?(range)
if whitespace_only && whitespace_is_indentation?(range, indent_level)
corrector.remove(range)
elsif !static?(heredoc)
range = range_between(range.begin_pos + indent_level, range.end_pos) if whitespace_only
corrector.wrap(range, "\#{'", "'}")
end
end
def whitespace_is_indentation?(range, level)
range.source[/[ \t]+/].length <= level
end
def whitespace_only?(range)
source = range_with_surrounding_space(range).source
source.start_with?("\n") && source.end_with?("\n")
end
def static?(heredoc)
heredoc.source.end_with? "'"
end
def skip_heredoc?
cop_config.fetch('AllowInHeredoc', false)
end
def find_heredoc(line_number)
heredocs.each { |node, r| return node if r.include?(line_number) }
nil
end
def heredocs
@heredocs ||= extract_heredocs(processed_source.ast)
end
def extract_heredocs(ast)
return [] unless ast
heredocs = []
ast.each_node(:str, :dstr, :xstr) do |node|
next unless node.heredoc?
body = node.location.heredoc_body
heredocs << [node, body.first_line...body.last_line]
end
heredocs
end
def offense_range(lineno, line)
source_range(processed_source.buffer, lineno, (line.rstrip.length)...(line.length))
end
end
end
end
end