Cover middleware freeze contracts.

lib/utopia/controller/rewrite.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2015-2025, by Samuel Williams.
+# Copyright, 2015-2026, by Samuel Williams.
 
 require_relative "../http"
 require_relative "../path/matcher"
@@ -48,6 +48,8 @@ def initialize(patterns, block)
 				# Freeze this object and its internal state.
 				# @returns [self] This object.
 				def freeze
+					return self if frozen?
+
 					@matcher.freeze
 					@block.freeze
 

test/utopia/content.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2012-2025, by Samuel Williams.
+# Copyright, 2012-2026, by Samuel Williams.
 
 require "sus/fixtures/protocol/http/middleware_context"
 require "utopia/application"
@@ -10,6 +10,28 @@
 describe Utopia::Content do
 	include Sus::Fixtures::Protocol::HTTP::MiddlewareContext
 
+	it "freezes its configuration" do
+		root = +File.expand_path(".content", __dir__)
+		namespaces = {
+			Utopia::Content::Middleware::CONTENT_NAMESPACE => Object.new,
+			Utopia::Content::Middleware::RELATIVE_NAMESPACE => Object.new,
+			Utopia::Content::Middleware::UTOPIA_NAMESPACE => Object.new,
+		}
+		middleware = Utopia::Content::Middleware.new(
+			Protocol::HTTP::Middleware::NotFound,
+			root: root,
+			namespaces: namespaces,
+		)
+
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(middleware).to be(:frozen?)
+		expect(middleware.freeze).to be_equal(middleware)
+
+		expect(root).to be(:frozen?)
+		expect(namespaces).to be(:frozen?)
+		namespaces.each_value{|namespace| expect(namespace).to be(:frozen?)}
+	end
+
 	let(:middleware) do
 		root = File.expand_path(".content", __dir__)
 

test/utopia/controller/middleware.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2013-2025, by Samuel Williams.
+# Copyright, 2013-2026, by Samuel Williams.
 
 require "sus/fixtures/protocol/http/middleware_context"
 require "utopia/application"
@@ -10,6 +10,23 @@
 describe Utopia::Controller do
 	include Sus::Fixtures::Protocol::HTTP::MiddlewareContext
 
+	it "freezes its configuration" do
+		root = +File.expand_path(".middleware", __dir__)
+		base = Class.new(Utopia::Controller::Base)
+		middleware = Utopia::Controller::Middleware.new(
+			Protocol::HTTP::Middleware::NotFound,
+			root: root,
+			base: base,
+		)
+
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(middleware).to be(:frozen?)
+		expect(middleware.freeze).to be_equal(middleware)
+
+		expect(root).to be(:frozen?)
+		expect(base).to be(:frozen?)
+	end
+
 	let(:middleware) do
 		root = File.expand_path(".middleware", __dir__)
 

test/utopia/controller/rewrite.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2015-2025, by Samuel Williams.
+# Copyright, 2015-2026, by Samuel Williams.
 
 require "utopia/controller"
 require "utopia/request"
@@ -38,6 +38,18 @@ def mock_request(path)
 		return request, request.path
 	end
 
+	it "freezes extraction rules" do
+		callback = proc{}
+		rule = Utopia::Controller::Rewrite::ExtractPrefixRule.new({id: Integer}, callback)
+
+		expect(rule.freeze).to be_equal(rule)
+		expect(rule).to be(:frozen?)
+		expect(rule.freeze).to be_equal(rule)
+
+		expect(rule.instance_variable_get(:@matcher)).to be(:frozen?)
+		expect(callback).to be(:frozen?)
+	end
+
 	it "should match path prefix and extract parameters" do
 		request, path = mock_request("/10/summary/20/edit")
 		relative_path = path - controller.class.uri_path

test/utopia/exceptions/handler.rb

@@ -20,6 +20,16 @@
 		end
 	end
 
+	it "freezes its configuration" do
+		location = +"/exception"
+		middleware = subject.new(Protocol::HTTP::Middleware::NotFound, location)
+
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(middleware).to be(:frozen?)
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(location).to be(:frozen?)
+	end
+
 	it "should successfully call the controller method" do
 		# This request will raise an exception, and then redirect to the /exception url which will fail again, and cause a fatal error.
 		client.get "/blow?fatal=true"

test/utopia/exceptions/mailer.rb

@@ -29,6 +29,29 @@ def before
 		super
 	end
 
+	it "freezes its configuration" do
+		to = +"postmaster@example.com"
+		from = +"utopia@example.com"
+		template = +"%{exception}"
+		delivery_method = [:test, {}]
+		middleware = subject.new(
+			Protocol::HTTP::Middleware::NotFound,
+			to: to,
+			from: from,
+			subject: template,
+			delivery_method: delivery_method,
+		)
+
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(middleware).to be(:frozen?)
+		expect(middleware.freeze).to be_equal(middleware)
+
+		expect(to).to be(:frozen?)
+		expect(from).to be(:frozen?)
+		expect(template).to be(:frozen?)
+		expect(delivery_method).to be(:frozen?)
+	end
+
 	it "should send an email to report the failure" do
 		client.headers["accept"] = "text/plain"
 

test/utopia/localization.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2014-2025, by Samuel Williams.
+# Copyright, 2014-2026, by Samuel Williams.
 
 require "sus/fixtures/protocol/http/middleware_context"
 require "utopia/application"
@@ -13,6 +13,31 @@
 describe Utopia::Localization do
 	include Sus::Fixtures::Protocol::HTTP::MiddlewareContext
 
+	it "freezes its configuration" do
+		default_locale = +"en"
+		default_locales = [default_locale, nil]
+		hosts = {/example\.com$/ => default_locale}
+		ignore = ["/health"]
+		middleware = Utopia::Localization::Middleware.new(
+			Protocol::HTTP::Middleware::NotFound,
+			locales: ["en"],
+			default_locale: default_locale,
+			default_locales: default_locales,
+			hosts: hosts,
+			ignore: ignore,
+		)
+
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(middleware).to be(:frozen?)
+		expect(middleware.freeze).to be_equal(middleware)
+
+		expect(middleware.all_locales).to be(:frozen?)
+		expect(default_locales).to be(:frozen?)
+		expect(default_locale).to be(:frozen?)
+		expect(hosts).to be(:frozen?)
+		expect(ignore).to be(:frozen?)
+	end
+
 	let(:middleware) do
 		root = File.expand_path(".localization", __dir__)
 

test/utopia/redirection.rb

@@ -53,6 +53,16 @@ def tracked_body(name, events)
 		expect(prefix).to be(:frozen?)
 	end
 
+	it "freezes error document configuration" do
+		codes = {404 => "/error"}
+		middleware = Utopia::Redirection::Errors.new(Protocol::HTTP::Middleware::NotFound, codes)
+
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(middleware).to be(:frozen?)
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(codes).to be(:frozen?)
+	end
+
 	let(:middleware) do
 		Utopia::Application.build(Protocol::HTTP::Middleware.for{|request|
 			case request.url.path.encoded

test/utopia/session.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2014-2025, by Samuel Williams.
+# Copyright, 2014-2026, by Samuel Williams.
 # Copyright, 2019, by Huba Nagy.
 
 require "sus/fixtures/protocol/http/middleware_context"
@@ -85,6 +85,26 @@
 end
 
 describe Utopia::Session::Middleware do
+	it "freezes its configuration" do
+		middleware = subject.new(
+			Protocol::HTTP::Middleware::NotFound,
+			session_name: "test.session",
+			secret: "secret",
+			expires_after: 3600,
+			update_timeout: 60,
+		)
+
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(middleware).to be(:frozen?)
+		expect(middleware.freeze).to be_equal(middleware)
+
+		expect(middleware.cookie_name).to be(:frozen?)
+		expect(middleware.key).to be(:frozen?)
+		expect(middleware.expires_after).to be(:frozen?)
+		expect(middleware.update_timeout).to be(:frozen?)
+		expect(middleware.cookie_defaults).to be(:frozen?)
+	end
+
 	let(:delegate) do
 		Protocol::HTTP::Middleware.for do |request|
 			request.session[:updated] = true

test/utopia/static.rb

@@ -12,6 +12,23 @@
 describe Utopia::Static do
 	include Sus::Fixtures::Protocol::HTTP::MiddlewareContext
 
+	it "freezes its configuration" do
+		cache_control = proc{"private"}
+		middleware = Utopia::Static::Middleware.new(
+			Protocol::HTTP::Middleware::NotFound,
+			root: File.expand_path(".static", __dir__),
+			cache_control: cache_control,
+		)
+
+		expect(middleware.freeze).to be_equal(middleware)
+		expect(middleware).to be(:frozen?)
+		expect(middleware.freeze).to be_equal(middleware)
+
+		expect(middleware.instance_variable_get(:@root)).to be(:frozen?)
+		expect(middleware.extensions).to be(:frozen?)
+		expect(cache_control).to be(:frozen?)
+	end
+
 	let(:middleware) do
 		root = File.expand_path(".static", __dir__)