From 657c60ee9054210c70a6e1bc786652fce72cb913 Mon Sep 17 00:00:00 2001
From: Daniel Vandersluis <daniel.vandersluis@gmail.com>
Date: Wed, 5 May 2021 10:30:59 -0400
Subject: [PATCH] [Fix #9773] Fix `Style/EmptyLiteral` to not register offenses
 for `String.new` when `Style/FrozenStringLiteral` is enabled.

---
 ...x_fix_styleemptyliteral_to_not_register.md |  1 +
 .../cop/mixin/frozen_string_literal.rb        |  6 +++
 lib/rubocop/cop/style/empty_literal.rb        |  9 ++++-
 spec/rubocop/cop/style/empty_literal_spec.rb  | 40 +++++++++++++++----
 4 files changed, 48 insertions(+), 8 deletions(-)
 create mode 100644 changelog/fix_fix_styleemptyliteral_to_not_register.md

diff --git a/changelog/fix_fix_styleemptyliteral_to_not_register.md b/changelog/fix_fix_styleemptyliteral_to_not_register.md
new file mode 100644
index 00000000000..9b2fa75719b
--- /dev/null
+++ b/changelog/fix_fix_styleemptyliteral_to_not_register.md
@@ -0,0 +1 @@
+* [#9773](https://github.com/rubocop/rubocop/issues/9773): Fix `Style/EmptyLiteral` to not register offenses for `String.new` when `Style/FrozenStringLiteral` is enabled. ([@dvandersluis][])
diff --git a/lib/rubocop/cop/mixin/frozen_string_literal.rb b/lib/rubocop/cop/mixin/frozen_string_literal.rb
index 42cad089a2e..14b9b0065f3 100644
--- a/lib/rubocop/cop/mixin/frozen_string_literal.rb
+++ b/lib/rubocop/cop/mixin/frozen_string_literal.rb
@@ -35,6 +35,12 @@ def frozen_string_literals_enabled?
         leading_comment_lines.any? { |line| MagicComment.parse(line).frozen_string_literal? }
       end
 
+      def frozen_string_literals_disabled?
+        leading_comment_lines.any? do |line|
+          MagicComment.parse(line).frozen_string_literal == false
+        end
+      end
+
       def frozen_string_literal_specified?
         leading_comment_lines.any? do |line|
           MagicComment.parse(line).frozen_string_literal_specified?
diff --git a/lib/rubocop/cop/style/empty_literal.rb b/lib/rubocop/cop/style/empty_literal.rb
index 87786097059..587f6b91d03 100644
--- a/lib/rubocop/cop/style/empty_literal.rb
+++ b/lib/rubocop/cop/style/empty_literal.rb
@@ -62,7 +62,7 @@ def offense_message(node)
             ARR_MSG
           elsif offense_hash_node?(node)
             HASH_MSG
-          elsif str_node(node) && !frozen_string_literals_enabled?
+          elsif str_node(node) && !frozen_strings?
             format(STR_MSG, prefer: preferred_string_literal)
           end
         end
@@ -125,6 +125,13 @@ def correction(node)
             end
           end
         end
+
+        def frozen_strings?
+          return true if frozen_string_literals_enabled?
+
+          frozen_string_cop_enabled = config.for_cop('Style/FrozenStringLiteral')['Enabled']
+          frozen_string_cop_enabled && !frozen_string_literals_disabled?
+        end
       end
     end
   end
diff --git a/spec/rubocop/cop/style/empty_literal_spec.rb b/spec/rubocop/cop/style/empty_literal_spec.rb
index 44df2bb45c7..e5d457a5a07 100644
--- a/spec/rubocop/cop/style/empty_literal_spec.rb
+++ b/spec/rubocop/cop/style/empty_literal_spec.rb
@@ -207,6 +207,8 @@ def foo
   end
 
   describe 'Empty String', :config do
+    let(:other_cops) { { 'Style/FrozenStringLiteral' => { 'Enabled' => false } } }
+
     it 'registers an offense for String.new()' do
       expect_offense(<<~RUBY)
         test = String.new()
@@ -249,13 +251,10 @@ def foo
     end
 
     context 'when double-quoted string literals are preferred' do
-      let(:config) do
-        RuboCop::Config.new(
-          'Style/StringLiterals' =>
-            {
-              'EnforcedStyle' => 'double_quotes'
-            }
-        )
+      let(:other_cops) do
+        super().merge('Style/StringLiterals' => {
+                        'EnforcedStyle' => 'double_quotes'
+                      })
       end
 
       it 'registers an offense for String.new' do
@@ -289,5 +288,32 @@ def foo
         RUBY
       end
     end
+
+    context 'when Style/FrozenStringLiteral is enabled' do
+      let(:other_cops) { { 'Style/FrozenStringLiteral' => { 'Enabled' => true } } }
+
+      context 'and there is no magic comment' do
+        it 'does not register an offense' do
+          expect_no_offenses(<<~RUBY)
+            test = String.new
+          RUBY
+        end
+      end
+
+      context 'and there is a frozen-string-literal: false comment' do
+        it 'registers an offense and corrects' do
+          expect_offense(<<~RUBY)
+            # frozen-string-literal: false
+            test = String.new
+                   ^^^^^^^^^^ Use string literal `''` instead of `String.new`.
+          RUBY
+
+          expect_correction(<<~RUBY)
+            # frozen-string-literal: false
+            test = ''
+          RUBY
+        end
+      end
+    end
   end
 end