diff --git a/.gitignore b/.gitignore
index 99eef04e54..f4692e2200 100644
--- a/.gitignore
+++ b/.gitignore
@@ -63,8 +63,6 @@
 !**/vendor/bundle/ruby/*/gems/activesupport-*/lib/active_support/
 !**/vendor/bundle/ruby/*/gems/activesupport-*/lib/active_support/core_ext/
 !**/vendor/bundle/ruby/*/gems/activesupport-*/lib/active_support/core_ext/*/
-!**/vendor/bundle/ruby/*/gems/activesupport-*/lib/active_support/core_ext/file/atomic.rb
-!**/vendor/bundle/ruby/*/gems/activesupport-*/lib/active_support/core_ext/hash/deep_merge.rb
 !**/vendor/bundle/ruby/*/gems/activesupport-*/lib/active_support/core_ext/hash/deep_transform_values.rb
 !**/vendor/bundle/ruby/*/gems/activesupport-*/lib/active_support/core_ext/hash/keys.rb
 !**/vendor/bundle/ruby/*/gems/activesupport-*/lib/active_support/core_ext/object/deep_dup.rb
diff --git a/Library/Homebrew/dev-cmd/bottle.rb b/Library/Homebrew/dev-cmd/bottle.rb
index 524674708d..7ebc235b33 100644
--- a/Library/Homebrew/dev-cmd/bottle.rb
+++ b/Library/Homebrew/dev-cmd/bottle.rb
@@ -11,6 +11,7 @@ require "utils/inreplace"
 require "erb"
 require "utils/gzip"
 require "api"
+require "extend/hash/deep_merge"
 
 BOTTLE_ERB = <<-EOS.freeze
   bottle do
diff --git a/Library/Homebrew/dev-cmd/pr-upload.rb b/Library/Homebrew/dev-cmd/pr-upload.rb
index 971a191e72..5f6fa25633 100644
--- a/Library/Homebrew/dev-cmd/pr-upload.rb
+++ b/Library/Homebrew/dev-cmd/pr-upload.rb
@@ -5,6 +5,7 @@ require "cli/parser"
 require "formula"
 require "github_packages"
 require "github_releases"
+require "extend/hash/deep_merge"
 
 module Homebrew
   module_function
diff --git a/Library/Homebrew/extend/array.rb b/Library/Homebrew/extend/array.rb
index 0163a2bb7f..152033304b 100644
--- a/Library/Homebrew/extend/array.rb
+++ b/Library/Homebrew/extend/array.rb
@@ -17,6 +17,11 @@ class Array
   #   %w( a b c d e ).fourth # => "d"
   def fourth = self[3]
 
+  # Equal to <tt>self[4]</tt>.
+  #
+  #   %w( a b c d e ).fifth # => "e"
+  def fifth = self[4]
+
   # Converts the array to a comma-separated sentence where the last element is
   # joined by the connector word.
   #
diff --git a/Library/Homebrew/extend/array.rbi b/Library/Homebrew/extend/array.rbi
index 0c1bb89dd7..3d9e293bd4 100644
--- a/Library/Homebrew/extend/array.rbi
+++ b/Library/Homebrew/extend/array.rbi
@@ -9,4 +9,7 @@ class Array
 
   sig { returns(T.nilable(Elem)) }
   def fourth; end
+
+  sig { returns(T.nilable(Elem)) }
+  def fifth; end
 end
diff --git a/Library/Homebrew/vendor/bundle/ruby/3.1.0/gems/activesupport-6.1.7.6/lib/active_support/core_ext/hash/deep_merge.rb b/Library/Homebrew/extend/hash/deep_merge.rb
similarity index 81%
rename from Library/Homebrew/vendor/bundle/ruby/3.1.0/gems/activesupport-6.1.7.6/lib/active_support/core_ext/hash/deep_merge.rb
rename to Library/Homebrew/extend/hash/deep_merge.rb
index 9bc50b7bc6..01ecbe9260 100644
--- a/Library/Homebrew/vendor/bundle/ruby/3.1.0/gems/activesupport-6.1.7.6/lib/active_support/core_ext/hash/deep_merge.rb
+++ b/Library/Homebrew/extend/hash/deep_merge.rb
@@ -1,3 +1,4 @@
+# typed: strict
 # frozen_string_literal: true
 
 class Hash
@@ -22,10 +23,10 @@ class Hash
   # Same as +deep_merge+, but modifies +self+.
   def deep_merge!(other_hash, &block)
     merge!(other_hash) do |key, this_val, other_val|
-      if this_val.is_a?(Hash) && other_val.is_a?(Hash)
-        this_val.deep_merge(other_val, &block)
-      elsif block_given?
-        block.call(key, this_val, other_val)
+      if T.unsafe(this_val).is_a?(Hash) && other_val.is_a?(Hash)
+        T.unsafe(this_val).deep_merge(other_val, &block)
+      elsif block
+        yield(key, this_val, other_val)
       else
         other_val
       end
diff --git a/Library/Homebrew/extend/hash/deep_merge.rbi b/Library/Homebrew/extend/hash/deep_merge.rbi
new file mode 100644
index 0000000000..ed5f3a9b6c
--- /dev/null
+++ b/Library/Homebrew/extend/hash/deep_merge.rbi
@@ -0,0 +1,20 @@
+# typed: strict
+# frozen_string_literal: true
+
+class Hash
+  sig do
+    type_parameters(:k2).params(
+      other_hash: T::Hash[T.type_parameter(:k2), T.untyped],
+      block: T.nilable(T.proc.params(k: T.untyped, v1: T.untyped, v2: T.untyped).returns(T.untyped))
+    ).returns(T::Hash[T.any(Hash::K, T.type_parameter(:k2)), T.untyped])
+  end
+  def deep_merge(other_hash, &block); end
+
+  sig do
+    type_parameters(:k2).params(
+      other_hash: T::Hash[T.type_parameter(:k2), T.untyped],
+      block: T.nilable(T.proc.params(k: T.untyped, v1: T.untyped, v2: T.untyped).returns(T.untyped))
+    ).returns(T::Hash[T.any(Hash::K, T.type_parameter(:k2)), T.untyped])
+  end
+  def deep_merge!(other_hash, &block); end
+end
diff --git a/Library/Homebrew/global.rb b/Library/Homebrew/global.rb
index 6bc52c9433..20e0482bb2 100644
--- a/Library/Homebrew/global.rb
+++ b/Library/Homebrew/global.rb
@@ -10,7 +10,6 @@ require "json/add/exception"
 require "forwardable"
 require "set"
 
-require "active_support/core_ext/hash/deep_merge"
 require "active_support/core_ext/hash/keys"
 
 HOMEBREW_API_DEFAULT_DOMAIN = ENV.fetch("HOMEBREW_API_DEFAULT_DOMAIN").freeze
diff --git a/Library/Homebrew/test/rubocop_spec.rb b/Library/Homebrew/test/rubocop_spec.rb
index ce163c2d98..dbf055d8fd 100644
--- a/Library/Homebrew/test/rubocop_spec.rb
+++ b/Library/Homebrew/test/rubocop_spec.rb
@@ -17,7 +17,7 @@ describe "RuboCop" do
     end
 
     it "loads all Formula cops without errors" do
-      stdout, stderr, status = Open3.capture3(RUBY_PATH, "-W0", "-S", "rubocop", TEST_FIXTURE_DIR/"testball.rb")
+      stdout, stderr, status = Open3.capture3(RUBY_PATH, "-W0", "-S", "rubocop", "-d", TEST_FIXTURE_DIR/"testball.rb")
       expect(stderr).to be_empty
       expect(stdout).to include("no offenses detected")
       expect(status).to be_a_success