[Fix rubocop#9691] Add configuration option InspectBlocks to Redundan…

…tLineBreak

Set the default value for this new configuration option to `false`, since we
suspect that many users might consider the `do`..`end` variant with line
breaks more readable.

For RuboCop's own sources we set it to `true`, i.e., the same behavior as
before the parameters existed, at least for now.

.rubocop.yml

@@ -49,6 +49,7 @@ Layout/ClassStructure:
 
 Layout/RedundantLineBreak:
   Enabled: true
+  InspectBlocks: true
 
 Layout/TrailingWhitespace:
   AllowInHeredoc: false

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### New features
 
 * [#7977](https://github.com/rubocop/rubocop/issues/7977): Add `Layout/RedundantLineBreak` cop. ([@jonas054][])
+* [#9691](https://github.com/rubocop/rubocop/issues/9691): Add configuration parameter `InspectBlocks` to `Layout/RedundantLineBreak`. ([@jonas054][])
 
 ## 1.12.1 (2021-04-04)
 

config/default.yml

@@ -1106,6 +1106,7 @@ Layout/RedundantLineBreak:
                  Do not break up an expression into multiple lines when it fits
                  on a single line.
   Enabled: false
+  InspectBlocks: false
   VersionAdded: '<<next>>'
 
 Layout/RescueEnsureAlignment:

lib/rubocop/cop/layout/redundant_line_break.rb

@@ -6,17 +6,13 @@ module Layout
       # This cop checks whether certain expressions, e.g. method calls, that could fit
       # completely on a single line, are broken up into multiple lines unnecessarily.
       #
-      # @example
+      # @example any configuration
       #   # bad
       #   foo(
       #     a,
       #     b
       #   )
       #
-      #   foo(a) do |x|
-      #     puts x
-      #   end
-      #
       #   puts 'string that fits on ' \
       #        'a single line'
       #
@@ -27,12 +23,25 @@ module Layout
       #   # good
       #   foo(a, b)
       #
-      #   foo(a) { |x| puts x }
-      #
       #   puts 'string that fits on a single line'
       #
       #   things.select { |thing| thing.cond? }.join('-')
       #
+      # @example InspectBlocks: false (default)
+      #   # good
+      #   foo(a) do |x|
+      #     puts x
+      #   end
+      #
+      # @example InspectBlocks: true
+      #   # bad
+      #   foo(a) do |x|
+      #     puts x
+      #   end
+      #
+      #   # good
+      #   foo(a) { |x| puts x }
+      #
       class RedundantLineBreak < Cop
         include CheckAssignment
 
@@ -64,7 +73,14 @@ def autocorrect(node)
         private
 
         def offense?(node)
-          !single_line?(node) && !too_long?(node) && suitable_as_single_line?(node)
+          return false if configured_to_not_be_inspected?(node)
+
+          node.multiline? && !too_long?(node) && suitable_as_single_line?(node)
+        end
+
+        def configured_to_not_be_inspected?(node)
+          !cop_config['InspectBlocks'] && (node.block_type? ||
+                                           node.each_child_node(:block).any?(&:multiline?))
         end
 
         def suitable_as_single_line?(node)
@@ -87,10 +103,6 @@ def comment_within?(node)
           end
         end
 
-        def single_line?(node)
-          node.first_line == node.last_line
-        end
-
         def too_long?(node)
           lines = processed_source.lines[(node.first_line - 1)...node.last_line]
           to_single_line(lines.join("\n")).length > max_line_length