Handle trailing line continuation in Layout/LineContinuationLeadingSpace

changelog/fix_handle_trailing_line_continuation_in_layout_line_continuation_leading_space.md

@@ -0,0 +1 @@
+* [#12581](https://github.com/rubocop/rubocop/pull/12581): Handle trailing line continuation in `Layout/LineContinuationLeadingSpace`. ([@eugeneius][])

lib/rubocop/cop/layout/line_continuation_leading_space.rb

@@ -107,7 +107,7 @@ def continuation?(line, line_num, node)
           return false unless line.end_with?("\\\n")
 
           # Ensure backslash isn't part of a token spanning to the next line.
-          node.children.none? { |c| c.first_line == line_num && c.multiline? }
+          node.children.none? { |c| (c.first_line...c.last_line).cover?(line_num) && c.multiline? }
         end
 
         def autocorrect(corrector, offense_range, insert_pos, spaces)

spec/rubocop/cop/layout/line_continuation_leading_space_spec.rb

@@ -113,6 +113,29 @@
       RUBY
     end
 
+    it 'registers no offense when multiline string ends with a line continuation' do
+      expect_no_offenses(<<~'RUBY')
+        "" "foo
+        bar\
+        "
+      RUBY
+    end
+
+    it 'registers an offense when multiline string ends on 1st line' do
+      expect_offense(<<~'RUBY')
+        "foo
+        bar" \
+        " baz"
+         ^ Move leading spaces to the end of previous line.
+      RUBY
+
+      expect_correction(<<~'RUBY')
+        "foo
+        bar " \
+        "baz"
+      RUBY
+    end
+
     describe 'interpolated strings' do
       it 'registers no offense on interpolated string alone' do
         expect_no_offenses(<<~'RUBY')