fix PolicyFinder when given an array with policy class override

lib/pundit/policy_finder.rb

@@ -36,7 +36,7 @@ def scope
     #   policy.update? #=> false
     #
     def policy
-      klass = find
+      klass = find(object)
       klass = klass.constantize if klass.is_a?(String)
       klass
     rescue NameError
@@ -48,15 +48,15 @@ def policy
     #
     def scope!
       raise NotDefinedError, "unable to find policy scope of nil" if object.nil?
-      scope or raise NotDefinedError, "unable to find scope `#{find}::Scope` for `#{object.inspect}`"
+      scope or raise NotDefinedError, "unable to find scope `#{find(object)}::Scope` for `#{object.inspect}`"
     end
 
     # @return [Class] policy class with query methods
     # @raise [NotDefinedError] if policy could not be determined
     #
     def policy!
       raise NotDefinedError, "unable to find policy of nil" if object.nil?
-      policy or raise NotDefinedError, "unable to find policy `#{find}` for `#{object.inspect}`"
+      policy or raise NotDefinedError, "unable to find policy `#{find(object)}` for `#{object.inspect}`"
     end
 
     # @return [String] the name of the key this object would have in a params hash
@@ -73,19 +73,20 @@ def param_key
 
   private
 
-    def find
-      if object.nil?
+    def find(subject)
+      if subject.nil?
         nil
-      elsif object.respond_to?(:policy_class)
-        object.policy_class
-      elsif object.class.respond_to?(:policy_class)
-        object.class.policy_class
+      elsif subject.is_a?(Array)
+        modules = subject.dup
+        last = modules.pop
+        context = modules.map { |x| find_class_name(x) }.join("::")
+        [context, find(last)].join("::")
+      elsif subject.respond_to?(:policy_class)
+        subject.policy_class
+      elsif subject.class.respond_to?(:policy_class)
+        subject.class.policy_class
       else
-        klass = if object.is_a?(Array)
-          object.map { |x| find_class_name(x) }.join("::")
-        else
-          find_class_name(object)
-        end
+        klass = find_class_name(subject)
         "#{klass}#{SUFFIX}"
       end
     end

spec/pundit_spec.rb

@@ -134,6 +134,13 @@
       expect(policy.post).to eq [:project, post]
     end
 
+    it "returns an instantiated policy given an array of a symbol and a model instance with policy_class override" do
+      policy = Pundit.policy(user, [:project, customer_post])
+      expect(policy.class).to eq Project::PostPolicy
+      expect(policy.user).to eq user
+      expect(policy.post).to eq [:project, customer_post]
+    end
+
     it "returns an instantiated policy given an array of a symbol and an active model instance" do
       policy = Pundit.policy(user, [:project, comment])
       expect(policy.class).to eq Project::CommentPolicy
@@ -155,6 +162,13 @@
       expect(policy.post).to eq [:project, Comment]
     end
 
+    it "returns an instantiated policy given an array of a symbol and a class with policy_class override" do
+      policy = Pundit.policy(user, [:project, Customer::Post])
+      expect(policy.class).to eq Project::PostPolicy
+      expect(policy.user).to eq user
+      expect(policy.post).to eq [:project, Customer::Post]
+    end
+
     it "returns correct policy class for an array of a multi-word symbols" do
       policy = Pundit.policy(user, [:project_one_two_three, :criteria_four_five_six])
       expect(policy.class).to eq ProjectOneTwoThree::CriteriaFourFiveSixPolicy

spec/spec_helper.rb

@@ -77,9 +77,13 @@ def model_name
       OpenStruct.new(param_key: "customer_post")
     end
 
-    def policy_class
+    def self.policy_class
       PostPolicy
     end
+
+    def policy_class
+      self.class.policy_class
+    end
   end
 end