lib/rubocop/cop/style/semicolon.rb
# frozen_string_literal: true
module RuboCop
module Cop
module Style
# Checks for multiple expressions placed on the same line.
# It also checks for lines terminated with a semicolon.
#
# This cop has `AllowAsExpressionSeparator` configuration option.
# It allows `;` to separate several expressions on the same line.
#
# @example
# # bad
# foo = 1; bar = 2;
# baz = 3;
#
# # good
# foo = 1
# bar = 2
# baz = 3
#
# @example AllowAsExpressionSeparator: false (default)
# # bad
# foo = 1; bar = 2
#
# @example AllowAsExpressionSeparator: true
# # good
# foo = 1; bar = 2
class Semicolon < Base
include RangeHelp
extend AutoCorrector
MSG = 'Do not use semicolons to terminate expressions.'
def self.autocorrect_incompatible_with
[Style::SingleLineMethods]
end
def on_new_investigation
return if processed_source.blank? || !processed_source.raw_source.include?(';')
check_for_line_terminator_or_opener
end
def on_begin(node)
return if cop_config['AllowAsExpressionSeparator']
return unless node.source.include?(';')
exprs = node.children
return if exprs.size < 2
expressions_per_line(exprs).each do |line, expr_on_line|
# Every line with more than one expression on it is a
# potential offense
next unless expr_on_line.size > 1
find_semicolon_positions(line) { |pos| register_semicolon(line, pos, true) }
end
end
private
def check_for_line_terminator_or_opener
each_semicolon do |line, column, token_before_semicolon|
register_semicolon(line, column, false, token_before_semicolon)
end
end
def each_semicolon
tokens_for_lines.each do |line, tokens|
semicolon_pos = semicolon_position(tokens)
after_expr_pos = semicolon_pos == -1 ? -2 : semicolon_pos
yield line, tokens[semicolon_pos].column, tokens[after_expr_pos] if semicolon_pos
end
end
def tokens_for_lines
processed_source.tokens.group_by(&:line)
end
# rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
def semicolon_position(tokens)
if tokens.last.semicolon?
-1
elsif tokens.first.semicolon?
0
elsif exist_semicolon_before_right_curly_brace?(tokens)
-3
elsif exist_semicolon_after_left_curly_brace?(tokens) ||
exist_semicolon_after_left_string_interpolation_brace?(tokens)
2
elsif exist_semicolon_after_left_lambda_curly_brace?(tokens)
3
elsif exist_semicolon_before_right_string_interpolation_brace?(tokens)
-4
end
end
# rubocop:enable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
def exist_semicolon_before_right_curly_brace?(tokens)
tokens[-2]&.right_curly_brace? && tokens[-3]&.semicolon?
end
def exist_semicolon_after_left_curly_brace?(tokens)
tokens[1]&.left_curly_brace? && tokens[2]&.semicolon?
end
def exist_semicolon_after_left_lambda_curly_brace?(tokens)
tokens[2]&.type == :tLAMBEG && tokens[3]&.semicolon?
end
def exist_semicolon_before_right_string_interpolation_brace?(tokens)
tokens[-3]&.type == :tSTRING_DEND && tokens[-4]&.semicolon?
end
def exist_semicolon_after_left_string_interpolation_brace?(tokens)
tokens[1]&.type == :tSTRING_DBEG && tokens[2]&.semicolon?
end
def register_semicolon(line, column, after_expression, token_before_semicolon = nil)
range = source_range(processed_source.buffer, line, column)
add_offense(range) do |corrector|
if after_expression
corrector.replace(range, "\n")
else
# Prevents becoming one range instance with subsequent line when endless range
# without parentheses.
# See: https://github.com/rubocop/rubocop/issues/10791
if token_before_semicolon&.regexp_dots?
range_node = find_range_node(token_before_semicolon)
corrector.wrap(range_node, '(', ')') if range_node
end
corrector.remove(range)
end
end
end
def expressions_per_line(exprs)
# create a map matching lines to the number of expressions on them
exprs_lines = exprs.map(&:first_line)
exprs_lines.group_by(&:itself)
end
def find_semicolon_positions(line)
# Scan for all the semicolons on the line
semicolons = processed_source[line - 1].enum_for(:scan, ';')
semicolons.each do
yield Regexp.last_match.begin(0)
end
end
def find_range_node(token_before_semicolon)
range_nodes.detect do |range_node|
range_node.source_range.contains?(token_before_semicolon.pos)
end
end
def range_nodes
return @range_nodes if instance_variable_defined?(:@range_nodes)
ast = processed_source.ast
@range_nodes = ast.range_type? ? [ast] : []
@range_nodes.concat(ast.each_descendant(:irange, :erange).to_a)
end
end
end
end
end