fix model cache for rails 3

Change-Id: I642731a7bb26580bf236fd275fd8ce30565ef2eb
Reviewed-on: https://gerrit.instructure.com/29553
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Willesen <jonw@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>

lib/model_cache.rb

@@ -102,10 +102,7 @@ module ModelCache
     return {} if records.empty?
 
     keys[records.first.class.name].inject({}) do |h, k|
-      h[k] = records.inject({}) do |h2, v|
-        h2[v.send(k)] = v
-        h2
-      end
+      h[k] = records.index_by(&k)
       h
     end
   end
@@ -118,10 +115,12 @@ module ModelCache
     orig_method = "super"
     alias_method = nil
 
-    if (options[:type] == :instance ? klass.instance_methods : klass.methods).map(&:to_s).include?(method.to_s)
-      orig_method = "#{method}_without_cache(*args)"
-      alias_method = "alias_method_chain #{method.inspect}, :cache"
-      method = "#{method}_with_cache"
+    if CANVAS_RAILS2
+      if (options[:type] == :instance ? klass.instance_methods : klass.methods).map(&:to_s).include?(method.to_s)
+        orig_method = "#{method}_without_cache(*args)"
+        alias_method = "alias_method_chain #{method.inspect}, :cache"
+        method = "#{method}_with_cache"
+      end
     end
 
     key_value = options[:key_method] || "args.first"

spec/lib/model_cache_spec.rb

@@ -19,7 +19,7 @@ require File.expand_path(File.dirname(__FILE__) + '/../spec_helper.rb')
 require 'lib/model_cache'
 
 describe ModelCache do
-  before do
+  before(:all) do
     class TestModelCacheUser < ActiveRecord::Base
       self.table_name = :users # reuse exiting tables so AR doesn't asplode
       include ModelCache
@@ -37,18 +37,22 @@ describe ModelCache do
 
       belongs_to :test_model_cache_user_copy, :class_name => 'TestModelCacheUser', :foreign_key => :user_id
     end
+  end
 
+  before do
     user_with_pseudonym(:name => 'qwerty')
     @user = TestModelCacheUser.where(:id => @user).first
     @pseudonym = TestModelCachePseudonym.where(:id => @pseudonym).first
   end
 
-  after do
+  after(:all) do
     ModelCache.keys.delete('TestModelCacheUser')
     ModelCache.keys.delete('TestModelCachePseudonym')
-    subclasses = ActiveRecord::Base.send(:class_variable_get, :@@subclasses)[ActiveRecord::Base]
-    subclasses.delete(TestModelCacheUser)
-    subclasses.delete(TestModelCachePseudonym)
+    if CANVAS_RAILS2
+      subclasses = ActiveRecord::Base.send(:class_variable_get, :@@subclasses)[ActiveRecord::Base]
+      subclasses.delete(TestModelCacheUser)
+      subclasses.delete(TestModelCachePseudonym)
+    end
     Object.send(:remove_const, :TestModelCacheUser)
     Object.send(:remove_const, :TestModelCachePseudonym)
   end