BZ 1238179 - VM Utilization screen generating charts throws internal server error after Rails 4

app/models/rbac.rb

@@ -445,7 +445,7 @@ def self.search(options = {})
   def self.method_with_scope(ar_scope, options)
     if ar_scope == VmdbDatabaseConnection
       ar_scope.all
-    elsif ar_scope < ActsAsArModel
+    elsif ar_scope < ActsAsArModel || (ar_scope.respond_to?(:instances_are_derived?) && ar_scope.instances_are_derived?)
       ar_scope.find(:all, options)
     else
       ar_scope.apply_legacy_finder_options(options)

lib/extensions/ar_merge_conditions.rb

@@ -31,9 +31,43 @@ def self.apply_legacy_finder_options(options)
       unknown_keys = options.keys - LEGACY_FINDER_METHODS.map(&:first)
       raise "Unsupported options #{unknown_keys}" unless unknown_keys.empty?
 
+      # Determine whether any of the included associations are polymorphic
+      has_polymorphic = included_associations(options[:include]).any? { |name| self.reflection_is_polymorphic?(name) }
+
       LEGACY_FINDER_METHODS.inject(all) { |scope, (key, method)|
+        # Don't call references method on scope if polymorphic associations are
+        # included to avoid ActiveRecord::EagerLoadPolymorphicError
+        next(scope) if method == :references && has_polymorphic
+        #
         options[key] ? scope.send(method, options[key]) : scope
       }
     end
+
+    def self.reflection_is_polymorphic?(name)
+      reflection = _reflect_on_association(name)
+      reflection ? reflection.polymorphic? : false
+    end
+
+    def self.included_associations(includes)
+      arr = []
+      _included_associations includes, arr
+      arr
+    end
+
+    def self._included_associations(includes, arr)
+      case includes
+      when Symbol, String
+        arr << includes.to_sym
+      when Array
+        includes.each do |assoc|
+          _included_associations assoc, arr
+        end
+      when Hash
+        includes.each do |k, v|
+          cache = arr << k
+          _included_associations v, cache
+        end
+      end
+    end
   end
 end

spec/lib/extensions/ar_merge_conditions_spec.rb

@@ -0,0 +1,47 @@
+require "spec_helper"
+
+describe ActiveRecord::Base do
+  context "calling apply_legacy_finder_options" do
+    before(:each) do
+      @vm = FactoryGirl.create(:vm_vmware)
+      @perf = FactoryGirl.create(
+        :metric_rollup_vm_daily,
+        :resource_id  => @vm.id,
+        :timestamp    => "2010-04-14T00:00:00Z",
+        :time_profile => @time_profile
+      )
+
+      # Typical includes for rendering daily metrics charts
+      @include = {
+        :max_derived_cpu_available       => {},
+        :max_derived_cpu_reserved        => {},
+        :min_cpu_usagemhz_rate_average   => {},
+        :max_cpu_usagemhz_rate_average   => {},
+        :min_cpu_usage_rate_average      => {},
+        :max_cpu_usage_rate_average      => {},
+        :v_pct_cpu_ready_delta_summation => {},
+        :v_pct_cpu_wait_delta_summation  => {},
+        :v_pct_cpu_used_delta_summation  => {},
+        :max_derived_memory_available    => {},
+        :max_derived_memory_reserved     => {},
+        :min_derived_memory_used         => {},
+        :max_derived_memory_used         => {},
+        :min_disk_usage_rate_average     => {},
+        :max_disk_usage_rate_average     => {},
+        :min_net_usage_rate_average      => {},
+        :max_net_usage_rate_average      => {},
+        :v_derived_storage_used          => {},
+        :resource                        => {}
+
+      }
+    end
+    it "should not raise an error when a polymorphic reflection is included" do
+      result = nil
+      expect do
+        result = MetricRollup.apply_legacy_finder_options(:include => @include).to_a
+      end.not_to raise_error
+
+      result.length.should == 1
+    end
+  end
+end

spec/models/metric_rollup_spec.rb

@@ -0,0 +1,22 @@
+require "spec_helper"
+
+describe MetricRollup do
+  context "test" do
+    it "should not raise an error when a polymorphic reflection is included and references are specified in a query" do
+      pending "until ActiveRecord is fixed"
+      # TODO: A fix in ActiveRecord will make this test pass
+      expect do
+        MetricRollup.where(:id => 1)
+          .includes(:resource => {}, :time_profile => {})
+          .references(:time_profile => {}).last
+      end.not_to raise_error
+
+      # TODO: Also, there is a bug that exists in only the manageiq repo and not rails
+      # TODO: that causes the error "ActiveRecord::ConfigurationError: nil"
+      # TODO: instead of the expected "ActiveRecord::EagerLoadPolymorphicError" error.
+      expect do
+        Tagging.includes(:taggable => {}).where('bogus_table.column = 1').references(:bogus_table => {}).to_a
+      end.to raise_error ActiveRecord::EagerLoadPolymorphicError
+    end
+  end
+end