don't include submissions in recent_stream_items

dashboards don't show these, and existing ones can be a little crazy if
they have lots of submission comments

also change cache key so these get regenerated

test plan:
1. dashboards should work
2. stream item api should work
3. specs should pass

Change-Id: I245f4464189a507f0e1a8c9dc1c4c1e9fd4b7566
Reviewed-on: https://gerrit.instructure.com/16502
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
QA-Review: Cam Theriault <cam@instructure.com>

app/models/user.rb

@@ -1875,6 +1875,7 @@ class User < ActiveRecord::Base
     instances
   end
 
+  # NOTE: excludes submission stream items
   def cached_recent_stream_items(opts={})
     expires_in = 1.day
 
@@ -1896,6 +1897,7 @@ class User < ActiveRecord::Base
     end
   end
 
+  # NOTE: excludes submission stream items
   def recent_stream_items(opts={})
     self.shard.activate do
       ActiveRecord::Base::ConnectionSpecification.with_environment(:slave) do
@@ -1905,7 +1907,9 @@ class User < ActiveRecord::Base
         })
         visible_instances.map do |sii|
           si = sii.stream_item
-          si.data.write_attribute(:unread, sii.unread?) if si.present?
+          next unless si.present?
+          next if si.asset_type == 'Submission'
+          si.data.write_attribute(:unread, sii.unread?)
           si
         end.compact
       end

app/observers/stream_item_cache.rb

@@ -44,7 +44,7 @@ class StreamItemCache < ActiveRecord::Observer
   # Generate a cache key for User#recent_stream_items
   def self.recent_stream_items_key(user, context_type = nil, context_id = nil)
     user_id = (user.is_a?(User) ? user.id : user)
-    ['recent_stream_items2', user_id, context_stream_item_key(context_type, context_id)].cache_key
+    ['recent_stream_items3', user_id, context_stream_item_key(context_type, context_id)].cache_key
   end
 
   # Returns a cached cache key for the context with the time so all

spec/models/user_spec.rb

@@ -157,6 +157,20 @@ describe User do
     @user.recent_stream_items.size.should == 0
   end
 
+  describe "#recent_stream_items" do
+    it "should skip submission stream items" do
+      course_with_teacher(:active_all => true)
+      course_with_student(:active_all => true, :course => @course)
+      assignment = @course.assignments.create!(:title => "some assignment", :submission_types => ['online_text_entry'])
+      sub = assignment.submit_homework @student, :submission_type => "online_text_entry", :body => "submission"
+      sub.add_comment :author => @teacher, :comment => "lol"
+      item = StreamItem.last
+      item.asset.should == sub
+      @student.visible_stream_item_instances.map(&:stream_item).should include item
+      @student.recent_stream_items.should_not include item
+    end
+  end
+
   describe "#cached_recent_stream_items" do
     before(:each) do
       @contexts = []