Validate configuration Hash mutation methods

docs/CHANGELOG.md

@@ -14,7 +14,7 @@ nav_order: 6
 
     *Joel Hawksley*
 
-* Raise `ViewComponent::UnknownConfigOptionError` when setting a `config.view_component` option that doesn't exist, rather than ignoring it. This includes options renamed or removed in 4.0, such as `preview_controller` (now `previews.controller`), and the error names the replacement. Replacing `previews` or `generate` with a hash preserves this validation.
+* Raise `ViewComponent::UnknownConfigOptionError` when setting a `config.view_component` option that doesn't exist, rather than ignoring it. This includes options renamed or removed in 4.0, such as `preview_controller` (now `previews.controller`), and the error names the replacement. Replacing `previews` or `generate` with a hash preserves this validation, including through Hash mutation methods such as `merge!`, `update`, `store`, and `replace`.
 
     *Fiona Burcombe*
 

docs/guide/generators.md

@@ -192,7 +192,7 @@ bin/rails generate view_component:component Example title content --parent MyBas
       create    app/components/example_component.html.erb
 ```
 
-To always use a specific parent class, set `config.view_component.parent_class = "MyBaseComponent"`.
+To always use a specific parent class, set `config.view_component.generate.parent_class = "MyBaseComponent"`.
 
 ### Skip collision check
 

lib/view_component/config.rb

@@ -15,19 +15,22 @@ def initialize(namespace, allowed_keys, default: nil, renamed: {}, removed: {})
         @allowed_keys = allowed_keys
         @renamed = renamed
         @removed = removed
+        @nested_options = {}
       end
 
       def []=(key, value)
         key = key.to_sym
 
         if @allowed_keys.include?(key)
-          if self[key].is_a?(Options)
+          @nested_options[key] ||= value if value.is_a?(Options)
+          if (nested_options = @nested_options[key])
             raise TypeError, "#{@namespace}.#{key} must be a Hash" unless value.is_a?(Hash)
 
-            value = self[key].dup.clear.tap do |options|
+            value = nested_options.dup.clear.tap do |options|
               value.each_pair { |nested_key, nested_value| options[nested_key] = nested_value }
             end
           end
+
           super
         else
           raise UnknownConfigOptionError.new(
@@ -39,6 +42,39 @@ def []=(key, value)
           )
         end
       end
+
+      alias_method :store, :[]=
+
+      def merge!(*others)
+        others.each do |other|
+          {}.merge!(other).each_pair do |key, value|
+            key = key.to_sym
+            value = yield(key, self[key], value) if block_given? && key?(key)
+            self[key] = value
+          end
+        end
+        self
+      end
+
+      alias_method :update, :merge!
+
+      def replace(other)
+        replacement = dup.clear
+        replacement.merge!(other)
+        super(replacement)
+      end
+
+      def transform_keys!(*args, &block)
+        return enum_for(:transform_keys!) if args.empty? && !block
+
+        replace(to_h.transform_keys!(*args, &block))
+      end
+
+      def transform_values!(&block)
+        return enum_for(:transform_values!) unless block
+
+        replace(to_h.transform_values!(&block))
+      end
     end
 
     # Options renamed in 4.0, mapped to their new name.
@@ -222,7 +258,7 @@ def default_generate_options
           "#{Options::ROOT_NAMESPACE}.generate",
           %i[path preview_path parent_class sidecar stimulus_controller typescript locale distinct_locale_files preview use_component_path_for_rspec_tests],
           default: false,
-          renamed: RENAMED_OPTIONS
+          renamed: {component_parent_class: RENAMED_OPTIONS.fetch(:component_parent_class)}
         )
         options.preview_path = ""
         options.path = "app/components"

test/sandbox/test/config_test.rb

@@ -69,6 +69,135 @@ def test_setting_an_option_removed_in_4_0_raises
       )
     end
 
+    def test_generate_options_do_not_use_root_rename_hints
+      error = assert_raises(ViewComponent::UnknownConfigOptionError) do
+        @config.generate.preview_paths = "spec/components/previews"
+      end
+
+      assert_includes error.message, "`config.view_component.generate.preview_paths` isn't a ViewComponent configuration option."
+      assert_includes error.message, "Valid options are: path, preview_path, parent_class"
+      refute_includes error.message, "was renamed"
+    end
+
+    def test_hash_writers_validate_keys
+      %i[merge! update replace].each do |method|
+        options = ViewComponent::Config.defaults
+        assert_raises(ViewComponent::UnknownConfigOptionError) do
+          options.public_send(method, preview_controller: "MyPreviewController")
+        end
+      end
+
+      assert_raises(ViewComponent::UnknownConfigOptionError) do
+        @config.store(:test_controller, "MyController")
+      end
+    end
+
+    def test_hash_writers_wrap_nested_namespaces
+      %i[merge! update replace store].each do |method|
+        options = ViewComponent::Config.defaults
+        if method == :store
+          options.store("generate", {"parent_class" => "MyBaseComponent"})
+        else
+          assert_same options, options.public_send(method, "generate" => {"parent_class" => "MyBaseComponent"})
+        end
+
+        assert_equal "MyBaseComponent", options.generate.parent_class
+        assert_equal false, options.generate.typescript
+        assert_raises(ViewComponent::UnknownConfigOptionError) { options.generate.typo = true }
+        assert_raises(ViewComponent::UnknownConfigOptionError) do
+          if method == :store
+            options.generate.store(:typo, true)
+          else
+            options.generate.public_send(method, typo: true)
+          end
+        end
+      end
+    end
+
+    def test_hash_writers_reject_invalid_nested_values
+      %i[merge! update replace store].each do |method|
+        options = ViewComponent::Config.defaults
+        [nil, {contoller: "MyPreviewController"}].each do |value|
+          original = options.previews
+          error = value.nil? ? TypeError : ViewComponent::UnknownConfigOptionError
+          assert_raises(error) do
+            if method == :store
+              options.store(:previews, value)
+            else
+              options.public_send(method, previews: value)
+            end
+          end
+          assert_same original, options.previews
+        end
+      end
+    end
+
+    def test_merge_accepts_multiple_hashes_and_a_conflict_block
+      options = @config.generate
+      conflicts = []
+      result = options.update({"path" => "lib/components"}, {path: "other/components", sidecar: true}) do |key, old, new|
+        conflicts << [key, old, new]
+        "#{old}/#{new}"
+      end
+
+      assert_same options, result
+      assert_equal "app/components/lib/components/other/components", options.path
+      assert_equal true, options.sidecar
+      assert_equal [
+        [:path, "app/components", "lib/components"],
+        [:path, "app/components/lib/components", "other/components"]
+      ], conflicts
+      assert_same options, options.merge!
+      assert_raises(TypeError) { options.merge!(nil) }
+      assert_raises(TypeError) { options.replace(nil) }
+    end
+
+    def test_replacing_options_validates_before_removing_existing_values
+      original = @config.previews.dup
+
+      assert_raises(ViewComponent::UnknownConfigOptionError) do
+        @config.previews.replace(controller: "MyPreviewController", typo: true)
+      end
+
+      assert_equal original, @config.previews
+    end
+
+    def test_removed_namespaces_retain_their_validation_when_reassigned
+      %i[clear replace delete shift].each do |method|
+        options = ViewComponent::Config.defaults
+        case method
+        when :replace then options.replace({})
+        when :delete then options.delete(:generate)
+        else options.public_send(method)
+        end
+        replacement = {generate: {parent_class: "MyBaseComponent"}}
+        options.merge!(replacement)
+
+        assert_equal "MyBaseComponent", options.generate.parent_class
+        assert_equal false, options.generate.typescript
+        assert_raises(ViewComponent::UnknownConfigOptionError) { options.generate.typo = true }
+      end
+    end
+
+    def test_transforming_keys_validates_new_keys
+      options = @config.generate
+      assert_kind_of Enumerator, options.transform_keys!
+      assert_same options, options.transform_keys!(&:to_s)
+      assert_raises(ViewComponent::UnknownConfigOptionError) do
+        options.transform_keys!(path: :typo)
+      end
+      assert_equal "app/components", options.path
+    end
+
+    def test_transforming_values_preserves_nested_validation
+      options = ViewComponent::Config.defaults
+      assert_kind_of Enumerator, options.transform_values!
+      assert_same options, options.transform_values! { |value| value.is_a?(Hash) ? value.to_h : value }
+      assert_equal false, options.generate.typescript
+      assert_raises(ViewComponent::UnknownConfigOptionError) { options.previews.typo = true }
+      assert_raises(TypeError) { options.transform_values! { nil } }
+    end
+
     def test_setting_a_misspelled_option_raises
       error = assert_raises(ViewComponent::UnknownConfigOptionError) do
         @config.instrumentaton_enabled = true