don't include all_dates in assignment api with too many overrides

test plan:
* in the rails console, configure the override threshold with

 Setting.set('assignment_all_dates_too_many_threshold', '5')

* an assignment more than 5 overrides should not return the
 'all_dates' value in the api, but rather 'all_dates_count'

* on the assignment index page, an assignment with more than 5
 overrides should still list "Multiple Dates" but no longer
 shows a tooltip

closes #CNVS-32277

Change-Id: I99df5ae0f482c745f00a2d4c9dcedbc8042f007c
Reviewed-on: https://gerrit.instructure.com/91478
Tested-by: Jenkins
Reviewed-by: Keith T. Garner <kgarner@instructure.com>
Reviewed-by: Matt Berns <mberns@instructure.com>
QA-Review: Heath Hales <hhales@instructure.com>
Product-Review: McCall Smith <mcsmith@instructure.com>

app/coffeescripts/models/Assignment.coffee

@@ -280,8 +280,12 @@ define [
         lock_at:   @get("lock_at")
 
     multipleDueDates: =>
-      dateGroups = @get("all_dates")
-      dateGroups && dateGroups.length > 1
+      count = @get("all_dates_count")
+      if count && count > 1
+        true
+      else
+        dateGroups = @get("all_dates")
+        dateGroups && dateGroups.length > 1
 
     hasDueDate: =>
       !@isPage()

app/views/jst/assignments/DateAvailableColumnView.handlebars

@@ -1,6 +1,7 @@
 {{#if multipleDueDates}}
   <strong>{{#t "available"}}Available{{/t}}</strong>
 
+  {{#if allDates}}
   <a title class="vdd_tooltip_link"
      aria-labelledby="vdd_tooltip_{{selector}}"
      data-tooltip-selector="#vdd_tooltip_{{selector}}"
@@ -25,6 +26,9 @@
       {{/each}}
     </dl>
   </div>
+  {{else}}
+    {{#t "multiple_dates"}}Multiple Dates{{/t}}
+  {{/if}}
 {{else}}
   <span class="default-dates">
     {{#with defaultDates}}

app/views/jst/assignments/DateDueColumnView.handlebars

@@ -1,6 +1,7 @@
 {{#if multipleDueDates}}
   <strong>{{#t "due"}}Due{{/t}}</strong>
 
+  {{#if allDates}}
   <a title class="vdd_tooltip_link"
      aria-labelledby="vdd_tooltip_{{selector}}"
      data-tooltip-selector="#vdd_tooltip_{{selector}}"
@@ -25,7 +26,9 @@
       {{/each}}
     </dl>
   </div>
-
+  {{else}}
+    {{#t "multiple_dates"}}Multiple Dates{{/t}}
+  {{/if}}
 {{else}}
   {{#if singleSectionDueDate}}
     <strong>{{#t "due_date"}}Due{{/t}}</strong>

lib/api/v1/assignment.rb

@@ -211,7 +211,13 @@ module Api::V1::Assignment
     end
 
     if opts[:include_all_dates] && assignment.assignment_overrides
-      hash['all_dates'] = assignment.dates_hash_visible_to(user)
+      override_count = assignment.assignment_overrides.loaded? ?
+        assignment.assignment_overrides.select(&:active?).count : assignment.assignment_overrides.active.count
+      if override_count < Setting.get('assignment_all_dates_too_many_threshold', '25').to_i
+        hash['all_dates'] = assignment.dates_hash_visible_to(user)
+      else
+        hash['all_dates_count'] = override_count
+      end
     end
 
     if opts[:include_module_ids]

spec/apis/v1/assignments_api_spec.rb

@@ -673,6 +673,35 @@ describe AssignmentsApiController, :include_lti_spec_helpers, type: :request do
       expect(assign['all_dates']).not_to be_nil
     end
 
+    it "doesn't include all_dates if there are too many" do
+      course_with_teacher_logged_in(:active_all => true)
+      s1 = student_in_course(:course => @course, :active_all => true).user
+      s2 = student_in_course(:course => @course, :active_all => true).user
+
+      a = @course.assignments.create!(:title => "all_date_test", :submission_types => "online_url", :only_visible_to_overrides => true)
+      o1 = assignment_override_model(:assignment => a)
+      os1 = o1.assignment_override_students.create!(:user => s1)
+
+      Setting.set('assignment_all_dates_too_many_threshold', '2')
+
+      @user = @teacher
+      json = api_call(:get,
+        "/api/v1/courses/#{@course.id}/assignments.json",
+        { :controller => 'assignments_api', :action => 'index', :format => 'json', :course_id => @course.id.to_s},
+        :include => ['all_dates'])
+      expect(json.first['all_dates'].count).to eq 1
+
+      o2 = assignment_override_model(:assignment => a)
+      os2 = o2.assignment_override_students.create!(:user => s2)
+
+      json = api_call(:get,
+        "/api/v1/courses/#{@course.id}/assignments.json",
+        { :controller => 'assignments_api', :action => 'index', :format => 'json', :course_id => @course.id.to_s},
+        :include => ['all_dates'])
+      expect(json.first['all_dates']).to be_nil
+      expect(json.first['all_dates_count']).to eq 2
+    end
+
 
     it "returns due dates as they apply to the user" do
       course_with_student(active_all: true)