release final grade override

closes: GRADE-1965

test plan:
 - This feature cannot be reversed
 - New Gradebook cannot be disabled if final grade override is either
 allowed or on

Change-Id: I398b6e0a370d2ab507cad088a7947d35be989037
Reviewed-on: https://gerrit.instructure.com/179263
Reviewed-by: Keith Garner <kgarner@instructure.com>
Reviewed-by: Gary Mei <gmei@instructure.com>
Tested-by: Jenkins
QA-Review: James Butters <jbutters@instructure.com>
Product-Review: Keith Garner <kgarner@instructure.com>

app/models/course.rb

@@ -3264,7 +3264,9 @@ class Course < ActiveRecord::Base
   # to identify the user can't move backwards, such as feature flags
   def gradebook_backwards_incompatible_features_enabled?
     # The old gradebook can't deal with late policies at all
-    return true if late_policy&.missing_submission_deduction_enabled? || late_policy&.late_submission_deduction_enabled?
+    return true if late_policy&.missing_submission_deduction_enabled? ||
+      late_policy&.late_submission_deduction_enabled? ||
+      feature_enabled?(:final_grades_override)
 
     # If you've used the grade tray status changes at all, you can't
     # go back. Even if set to none, it'll break "Message Students

lib/feature.rb

@@ -249,7 +249,6 @@ END
       state: 'allowed',
       root_opt_in: true,
       beta: true,
-
       custom_transition_proc: ->(user, context, _from_state, transitions) do
         if context.is_a?(Course)
           if !context.grants_right?(user, :change_course_state)
@@ -260,13 +259,14 @@ END
             transitions['off']['locked'] = should_lock if transitions&.dig('off')
           end
         elsif context.is_a?(Account)
-          new_gradebook_feature_flag = FeatureFlag.where(feature: :new_gradebook, state: :on)
+          backwards_incompatible_feature_flags =
+            FeatureFlag.where(feature: [:new_gradebook, :final_grades_override], state: :on)
           all_active_sub_account_ids = Account.sub_account_ids_recursive(context.id)
           relevant_accounts = Account.joins(:feature_flags).where(id: [context.id].concat(all_active_sub_account_ids))
           relevant_courses = Course.joins(:feature_flags).where(account_id: all_active_sub_account_ids)
 
-          accounts_with_feature = relevant_accounts.merge(new_gradebook_feature_flag)
-          courses_with_feature = relevant_courses.merge(new_gradebook_feature_flag)
+          accounts_with_feature = relevant_accounts.merge(backwards_incompatible_feature_flags)
+          courses_with_feature = relevant_courses.merge(backwards_incompatible_feature_flags)
 
           if accounts_with_feature.exists? || courses_with_feature.exists?
             transitions['off'] ||= {}
@@ -277,6 +277,33 @@ END
         end
       end
     },
+    'final_grades_override' => {
+      display_name: -> { I18n.t('Final Grade Override') },
+      description: -> {
+        I18n.t <<~DESCRIPTION
+          Enable ability to alter the final grade for the entire course without changing scores for assignments.
+        DESCRIPTION
+      },
+      applies_to: 'Course',
+      root_opt_in: true,
+      state: 'allowed',
+      beta: true,
+      custom_transition_proc: ->(_user, context, from_state, transitions) do
+        # can't go back
+        if context.is_a?(Course) && from_state == 'on'
+          transitions['off'] ||= {}
+          transitions['off']['locked'] = true
+        elsif context.is_a?(Account) && from_state == 'allowed'
+          transitions['off'] ||= {}
+          transitions['off']['locked'] = true
+        elsif context.is_a?(Account) && from_state == 'on'
+          transitions['off'] ||= {}
+          transitions['off']['locked'] = true
+          transitions['allowed'] ||= {}
+          transitions['allowed']['locked'] = true
+        end
+      end
+    },
     'k12' =>
     {
       display_name: -> { I18n.t('features.k12', 'K-12 Specific Features') },
@@ -676,18 +703,6 @@ END
       applies_to: 'Course',
       state: 'allowed',
       development: true
-    },
-    'final_grades_override' => {
-      display_name: -> { I18n.t('Final Grade Override') },
-      description: -> {
-        I18n.t <<~DESCRIPTION
-          Enable ability to alter the final grade for the entire course without changing scores for assignments.
-        DESCRIPTION
-      },
-      applies_to: 'Course',
-      state: 'hidden',
-      development: true,
-      beta: true
     }
   )
 

spec/models/course_spec.rb

@@ -5279,6 +5279,10 @@ describe Course, "#show_total_grade_as_points?" do
   describe Course, "#gradebook_backwards_incompatible_features_enabled?" do
     let(:course) { Course.create! }
 
+    it "returns false if there are no policies nor is final_grade_override enabled" do
+      expect(course).not_to be_gradebook_backwards_incompatible_features_enabled
+    end
+
     it "returns true if a late policy is enabled" do
       course.late_policy = LatePolicy.new(late_submission_deduction_enabled: true)
 
@@ -5291,6 +5295,11 @@ describe Course, "#show_total_grade_as_points?" do
       expect(course.gradebook_backwards_incompatible_features_enabled?).to be true
     end
 
+    it 'is backward incompatible if final_grades_override is enabled' do
+      course.enable_feature!(:final_grades_override)
+      expect(course).to be_gradebook_backwards_incompatible_features_enabled
+    end
+
     it "returns true if both a late and missing policy are enabled" do
       course.late_policy =
         LatePolicy.new(late_submission_deduction_enabled: true, missing_submission_deduction_enabled: true)
@@ -5298,10 +5307,6 @@ describe Course, "#show_total_grade_as_points?" do
       expect(course.gradebook_backwards_incompatible_features_enabled?).to be true
     end
 
-    it "returns false if there are no policies" do
-      expect(course.gradebook_backwards_incompatible_features_enabled?).to be false
-    end
-
     it "returns false if both policies are disabled" do
       course.late_policy =
         LatePolicy.new(late_submission_deduction_enabled: false, missing_submission_deduction_enabled: false)