Ensure that preference keys are not prefixed with '/' if ENV['RAILS_C…

…ACHE_KEY'] is not set

Fixes spree#3831

core/app/models/spree/preferences/configuration.rb

@@ -29,7 +29,11 @@ def configure
     end
 
     def preference_cache_key(name)
-      [ENV['RAILS_CACHE_ID'], self.class.name, name].flatten.join('::').underscore
+      [rails_cache_id, self.class.name, name].compact.join('::').underscore
+    end
+
+    def rails_cache_id
+      ENV['RAILS_CACHE_ID']
     end
 
     def reset

core/app/models/spree/preferences/preferable.rb

@@ -78,7 +78,11 @@ def prefers?(name)
 
   def preference_cache_key(name)
     return unless id
-    [ENV["RAILS_CACHE_ID"], self.class.name, name, id].join('::').underscore
+    [rails_cache_id, self.class.name, name, id].compact.join('::').underscore
+  end
+
+  def rails_cache_id
+    ENV['RAILS_CACHE_ID']
   end
 
   def save_pending_preferences

core/spec/models/spree/preferences/configuration_spec.rb

@@ -9,6 +9,23 @@ class AppConfig < Spree::Preferences::Configuration
     @config = AppConfig.new
   end
 
+  # Regression test for #3831
+  context "with a rails cache id set" do
+    before do
+      @config.stub :rails_cache_id => "cache"
+    end
+
+    it "can access the preference cache key" do
+      expect(@config.preference_cache_key("foo")).to eql("cache/app_config/foo")
+    end
+  end
+
+  context "with no rails cache id set" do
+    it "does not prefix the preference cache key with a slash" do
+      expect(@config.preference_cache_key("foo")).to eql("app_config/foo")
+    end
+  end
+
   it "has named methods to access preferences" do
     @config.color = 'orange'
     @config.color.should eq 'orange'

core/spec/models/spree/preferences/preferable_spec.rb

@@ -31,6 +31,26 @@ class B < A
     store.persistence = true
   end
 
+  # Regression test for #3831
+  describe "preference cache key" do
+    context "with a rails_cache_id set" do
+      before do
+        @a.stub(:rails_cache_id => 'cache')
+      end
+
+      it "includes the cache id within the key" do
+        expect(@a.preference_cache_key('foo')).to eql("cache/a/foo/#{@a.id}")
+      end
+    end
+
+    context "without a rails_cache_id set" do
+      it "includes the cache id within the key" do
+        expect(@a.preference_cache_key('foo')).to eql("a/foo/#{@a.id}")
+      end
+    end
+
+  end
+
   describe "preference definitions" do
     it "parent should not see child definitions" do
       @a.has_preference?(:color).should be_true