[Fix rubocop#7534] Fix an incorrect autocorrect for `Layout/SpaceBefo…

…reBlockBraces`

Fixes rubocop#7534.

Fix an incorrect autocorrect for `Style/BlockDelimiters` cop and
`Layout/SpaceBeforeBlockBraces` cop with `EnforcedStyle: no_space`
when using multiline braces.

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 * [#7530](https://github.com/rubocop-hq/rubocop/issues/7530): Typo in `Style/TrivialAccessors`'s `AllowedMethods`. ([@movermeyer][])
 * [#7532](https://github.com/rubocop-hq/rubocop/issues/7532): Fix an error for `Style/TrailingCommaInArguments` when using an anonymous function with multiple line arguments with `EnforcedStyleForMultiline: consistent_comma`. ([@koic][])
+* [#7534](https://github.com/rubocop-hq/rubocop/issues/7534): Fix an incorrect autocorrect for `Style/BlockDelimiters` cop and `Layout/SpaceBeforeBlockBraces` cop with `EnforcedStyle: no_space` when using multiline braces. ([@koic][])
 
 ## 0.77.0 (2019-11-27)
 

lib/rubocop/cop/layout/space_before_block_braces.rb

@@ -41,6 +41,14 @@ def self.autocorrect_incompatible_with
         def on_block(node)
           return if node.keywords?
 
+          # Do not register an offense for multi-line braces when specifying
+          # `EnforcedStyle: no_space`. It will conflict with auto-correction
+          # by `EnforcedStyle: line_count_based` of `Style/BlockDelimiters` cop.
+          # That means preventing auto-correction to incorrect auto-corrected
+          # code.
+          # See: https://github.com/rubocop-hq/rubocop/issues/7534
+          return if conflict_with_block_delimiters?
+
           left_brace = node.loc.begin
           space_plus_brace = range_with_surrounding_space(range: left_brace)
           used_style =
@@ -110,6 +118,15 @@ def style_for_empty_braces
           end
         end
 
+        def conflict_with_block_delimiters?
+          block_delimiters_style == 'line_count_based' &&
+            style == :no_space && node.multiline?
+        end
+
+        def block_delimiters_style
+          config.for_cop('Style/BlockDelimiters')['EnforcedStyle']
+        end
+
         def empty_braces?(loc)
           loc.begin.end_pos == loc.end.begin_pos
         end

spec/rubocop/cli/cli_autocorrect_spec.rb

@@ -1653,6 +1653,32 @@ def self.some_method(foo, bar: 1)
     RUBY
   end
 
+  it 'corrects Style/BlockDelimiters offenses when specifing' \
+     'Layout/SpaceBeforeBlockBraces with `EnforcedStyle: no_space` together' do
+    create_file('example.rb', <<~RUBY)
+      foo {
+        bar
+      }
+    RUBY
+
+    create_file('.rubocop.yml', <<~YAML)
+      Layout/SpaceBeforeBlockBraces:
+        EnforcedStyle: no_space
+    YAML
+
+    expect(cli.run([
+                     '--auto-correct',
+                     '--only',
+                     'Style/BlockDelimiters,Layout/SpaceBeforeBlockBraces'
+                   ])).to eq(0)
+    expect($stderr.string).to eq('')
+    expect(IO.read('example.rb')).to eq(<<~RUBY)
+      foo do
+        bar
+      end
+    RUBY
+  end
+
   it 'corrects BracesAroundHashParameters offenses leaving the ' \
      'MultilineHashBraceLayout offense unchanged' do
     create_file('example.rb', <<~RUBY)