Merge pull request #12550 from koic/fix_a_false_positive_for_style_re…

…dundant_line_continuation

[Fix #12549] Fix a false positive for `Style/RedundantLineContinuation`

changelog/fix_a_false_positive_for_style_redundant_line_continuation.md

@@ -0,0 +1 @@
+* [#12549](https://github.com/rubocop/rubocop/issues/12549): Fix a false positive for `Style/RedundantLineContinuation` when line continuations for multiline leading dot method chain with a blank line. ([@koic][])

lib/rubocop/cop/style/redundant_line_continuation.rb

@@ -94,7 +94,8 @@ def require_line_continuation?(range)
           !ends_with_backslash_without_comment?(range.source_line) ||
             string_concatenation?(range.source_line) ||
             start_with_arithmetic_operator?(processed_source[range.line]) ||
-            inside_string_literal_or_method_with_argument?(range)
+            inside_string_literal_or_method_with_argument?(range) ||
+            leading_dot_method_chain_with_blank_line?(range)
         end
 
         def ends_with_backslash_without_comment?(source_line)
@@ -113,6 +114,12 @@ def inside_string_literal_or_method_with_argument?(range)
           end
         end
 
+        def leading_dot_method_chain_with_blank_line?(range)
+          return false unless range.source_line.strip.start_with?('.', '&.')
+
+          processed_source[range.line].strip.empty?
+        end
+
         def redundant_line_continuation?(range)
           return true unless (node = find_node_for_line(range.line))
           return false if argument_newline?(node)

spec/rubocop/cop/style/redundant_line_continuation_spec.rb

@@ -114,6 +114,80 @@ def self.foo(bar,#{trailing_whitespace}
     RUBY
   end
 
+  it 'does not register an offense when required line continuations for multiline leading dot method chain with an empty line' do
+    expect_no_offenses(<<~'RUBY')
+      obj
+       .foo(42) \
+
+       .bar
+    RUBY
+  end
+
+  it 'does not register an offense when required line continuations for multiline leading dot safe navigation method chain with an empty line' do
+    expect_no_offenses(<<~'RUBY')
+      obj
+       &.foo(42) \
+
+       .bar
+    RUBY
+  end
+
+  it 'does not register an offense when required line continuations for multiline leading dot method chain with a blank line' do
+    expect_no_offenses(<<~RUBY)
+      obj
+       .foo(42) \\
+      #{' '}
+       .bar
+    RUBY
+  end
+
+  it 'registers an offense when redundant line continuations for multiline leading dot method chain without an empty line' do
+    expect_offense(<<~'RUBY')
+      obj
+       .foo(42) \
+                ^ Redundant line continuation.
+       .bar
+    RUBY
+
+    expect_correction(<<~RUBY)
+      obj
+       .foo(42)#{' '}
+       .bar
+    RUBY
+  end
+
+  it 'registers an offense when redundant line continuations for multiline trailing dot method chain with an empty line' do
+    expect_offense(<<~'RUBY')
+      obj.
+       foo(42). \
+                ^ Redundant line continuation.
+
+       bar
+    RUBY
+
+    expect_correction(<<~RUBY)
+      obj.
+       foo(42).#{' '}
+
+       bar
+    RUBY
+  end
+
+  it 'registers an offense when redundant line continuations for multiline trailing dot method chain without an empty line' do
+    expect_offense(<<~'RUBY')
+      obj.
+       foo(42). \
+                ^ Redundant line continuation.
+       bar
+    RUBY
+
+    expect_correction(<<~RUBY)
+      obj.
+       foo(42).#{' '}
+       bar
+    RUBY
+  end
+
   it 'registers an offense when redundant line continuations for array' do
     expect_offense(<<~'RUBY')
       [foo, \