Improve StringExtension method_missing

3 files changed, 20 insertions, 3 deletions

diff --git a/.rubocop.yml b/.rubocop.yml
index afc480d..3ab76a8 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -54,3 +54,8 @@ Style/Encoding:
 Style/OptionalArguments:
   Exclude:
     - 'lib/highline/list_renderer.rb'
+
+# TemplateRenderer should never fail on method missing.
+Style/MethodMissing:
+  Exclude:
+    - 'lib/highline/template_renderer.rb'
diff --git a/lib/highline/string_extensions.rb b/lib/highline/string_extensions.rb
index aab4c27..bdeaf5a 100644
--- a/lib/highline/string_extensions.rb
+++ b/lib/highline/string_extensions.rb
@@ -11,6 +11,8 @@ class HighLine
   # HighLine extensions for String class.
   # Included by HighLine::String.
   module StringExtensions
+    STYLE_METHOD_NAME_PATTERN = /^(on_)?rgb_([0-9a-fA-F]{6})$/
+
     # Included hook. Actions to take when being included.
     # @param base [Class, Module] base class
     def self.included(base)
@@ -58,14 +60,18 @@ class HighLine
         # @todo Chain existing method_missing?
         undef :method_missing if method_defined? :method_missing
         def method_missing(method, *_args)
-          if method.to_s =~ /^(on_)?rgb_([0-9a-fA-F]{6})$/
+          if method.to_s =~ STYLE_METHOD_NAME_PATTERN
             color(method)
           else
-            raise NoMethodError, "undefined method `#{method}' for" /
-                                 "#<#{self.class}:#{format('%#x', object_id)}>"
+            super
           end
         end
 
+        undef :respond_to_missing if method_defined? :respond_to_missing
+        def respond_to_missing?(method_name, include_private = false)
+          method_name.to_s =~ STYLE_METHOD_NAME_PATTERN || super
+        end
+
         private
 
         def setup_color_code(*colors)
diff --git a/test/test_string_extension.rb b/test/test_string_extension.rb
index 44b514e..125f48e 100644
--- a/test/test_string_extension.rb
+++ b/test/test_string_extension.rb
@@ -71,4 +71,10 @@ class TestStringExtension < Minitest::Test
     end
     assert_equal 1, @include_received
   end
+
+  def test_respond_to_dynamic_style_methods
+    string = HighLine::String.new("pirarucu")
+    assert_respond_to(string, :on_rgb_123456)
+    assert_respond_to(string, :rgb_abcdef)
+  end
 end