ee/app/finders/epics_finder.rb

@@ -33,6 +33,7 @@ def execute
     items = by_state(items)
     items = by_label(items)
     items = by_parent(items)
+    items = by_iids(items)
 
     sort(items)
   end
@@ -49,7 +50,14 @@ def group
 
   # rubocop: disable CodeReuse/ActiveRecord
   def init_collection
-    groups = groups_user_can_read_epics(group.self_and_descendants)
+    groups = if params[:iids].present?
+               # If we are querying for specific iids, then we should only be looking at
+               # those in the group, not any sub-groups (which can have identical iids).
+               # The `group` method takes care of checking permissions
+               [group]
+             else
+               groups_user_can_read_epics(group.self_and_descendants)
+             end
 
     Epic.where(group: groups)
   end

ee/app/helpers/ee/issuables_helper.rb

@@ -22,6 +22,7 @@ def issuable_initial_data(issuable)
         data[:issueLinksEndpoint] = group_epic_issues_path(parent, issuable)
         data[:epicLinksEndpoint] = group_epic_links_path(parent, issuable)
         data[:subepicsSupported] = ::Epic.supports_nested_objects?
+        data[:fullPath] = parent.full_path
       end
 
       data

ee/app/models/ee/epic.rb

@@ -280,7 +280,11 @@ def has_ancestor?(epic)
     end
 
     def has_children?
-      issues.any? || descendants.any?
+      descendants.any?
+    end
+
+    def has_issues?
+      issues.any?
     end
 
     def child?(id)

ee/app/serializers/linked_epic_entity.rb

@@ -3,7 +3,7 @@
 class LinkedEpicEntity < Grape::Entity
   include RequestAwareEntity
 
-  expose :id, :title, :state
+  expose :id, :iid, :title, :state, :created_at, :closed_at
 
   expose :reference do |epic|
     epic.to_reference(request.issuable.group)
@@ -16,4 +16,20 @@ class LinkedEpicEntity < Grape::Entity
   expose :relation_path do |epic|
     group_epic_link_path(request.issuable.group, request.issuable.iid, epic.id)
   end
+
+  expose :has_children do |epic|
+    epic.has_children?
+  end
+
+  expose :has_issues do |epic|
+    epic.has_issues?
+  end
+
+  expose :full_path do |epic|
+    epic.group.full_path
+  end
+
+  expose :can_admin do |epic|
+    can?(request.current_user, :admin_epic, epic)
+  end
 end

ee/lib/ee/api/entities.rb

@@ -208,6 +208,7 @@ class LinkedEpic < Grape::Entity
         expose :group_id
         expose :parent_id
         expose :has_children?, as: :has_children
+        expose :has_issues?, as: :has_issues
         expose :reference do |epic|
           epic.to_reference(epic.parent.group)
         end

ee/spec/finders/epics_finder_spec.rb

@@ -27,7 +27,7 @@ def epics(params = {})
       end
     end
 
-    # Enabeling the `request_store` for this to avoid counting queries that check
+    # Enabling the `request_store` for this to avoid counting queries that check
     # the license.
     context 'when epics feature is enabled', :request_store do
       before do
@@ -178,6 +178,23 @@ def epics(params = {})
             expect(epics(params)).to contain_exactly(epic2)
           end
         end
+
+        context 'by iids' do
+          let(:subgroup)  { create(:group, :private, parent: group) }
+          let!(:subepic1) { create(:epic, group: subgroup, iid: epic1.iid) }
+
+          it 'returns the specified epics' do
+            params = { iids: [epic1.iid, epic2.iid] }
+
+            expect(epics(params)).to contain_exactly(epic1, epic2)
+          end
+
+          it 'does not return epics from the sub-group with the same iid' do
+            params = { iids: [epic1.iid] }
+
+            expect(epics(params)).to contain_exactly(epic1)
+          end
+        end
       end
     end
   end

ee/spec/fixtures/api/schemas/public_api/v4/linked_epic.json

@@ -7,12 +7,13 @@
     "group_id": { "type": "integer" },
     "parent_id": { "type": ["integer", "null"] },
     "has_children": { "type": "boolean" },
+    "has_issues": { "type": "boolean" },
     "reference": { "type": "string" },
     "url": { "type": "string" },
     "relation_url": { "type": "string" }
   },
   "required": [
-    "id", "iid", "group_id", "title", "parent_id", "has_children", "reference", "url", "relation_url"
+    "id", "iid", "group_id", "title", "parent_id", "has_children", "has_issues", "reference", "url", "relation_url"
   ],
   "additionalProperties": false
 }

ee/spec/helpers/ee/issuables_helper_spec.rb

@@ -29,6 +29,7 @@
         markdownDocsPath: '/help/user/markdown',
         issuableTemplates: nil,
         lockVersion: epic.lock_version,
+        fullPath: @group.full_path,
         groupPath: @group.path,
         initialTitleHtml: epic.title,
         initialTitleText: epic.title,

ee/spec/models/epic_spec.rb

@@ -722,6 +722,34 @@ def setup_control_group
     end
   end
 
+  describe '#has_children?' do
+    let(:epic) { create(:epic, group: group) }
+
+    it 'has no children' do
+      expect(epic.has_children?).to be_falsey
+    end
+
+    it 'has child epics' do
+      create(:epic, group: group, parent: epic)
+
+      expect(epic.has_children?).to be_truthy
+    end
+  end
+
+  describe '#has_issues?' do
+    let(:epic) { create(:epic, group: group) }
+
+    it 'has no issues' do
+      expect(epic.has_issues?).to be_falsey
+    end
+
+    it 'has child issues' do
+      create(:epic_issue, epic: epic, issue: create(:issue))
+
+      expect(epic.has_issues?).to be_truthy
+    end
+  end
+
   context 'mentioning other objects' do
     let(:epic) { create(:epic, group: group) }
 

ee/spec/services/epic_links/list_service_spec.rb

@@ -14,15 +14,33 @@ def epics_to_results(epics)
     epics.map do |epic|
       {
         id: epic.id,
+        iid: epic.iid,
         title: epic.title,
         state: epic.state,
+        created_at: epic.created_at,
+        closed_at: epic.closed_at,
         reference: epic.to_reference(group),
         path: "/groups/#{epic.group.full_path}/-/epics/#{epic.iid}",
-        relation_path: "/groups/#{parent_epic.group.full_path}/-/epics/#{parent_epic.iid}/links/#{epic.id}"
+        relation_path: "/groups/#{parent_epic.group.full_path}/-/epics/#{parent_epic.iid}/links/#{epic.id}",
+        has_children: epic.has_children?,
+        has_issues: epic.has_issues?,
+        full_path: epic.group.full_path,
+        can_admin: Ability.allowed?(user, :admin_epic, epic)
       }
     end
   end
 
+  def expect_results_are_equal(results, expected)
+    results.each_index do |index|
+      expect(results[index][:created_at]).to be_like_time(expected[index][:created_at])
+    end
+
+    results.each  { |h| h.delete(:created_at) }
+    expected.each { |h| h.delete(:created_at) }
+
+    expect(results).to eq(expected)
+  end
+
   describe '#execute' do
     subject { described_class.new(parent_epic, user).execute }
 
@@ -47,7 +65,7 @@ def epics_to_results(epics)
         it 'returns related issues JSON' do
           expected_result = epics_to_results([epic1, epic2])
 
-          expect(subject).to eq(expected_result)
+          expect_results_are_equal(subject, expected_result)
         end
       end
 
@@ -62,7 +80,7 @@ def epics_to_results(epics)
 
           expected_result = epics_to_results([epic1, epic2, epic_subgroup2, epic_subgroup1])
 
-          expect(subject).to eq(expected_result)
+          expect_results_are_equal(subject, expected_result)
         end
 
         it 'returns only some child epics for a subgroup member' do
@@ -70,7 +88,7 @@ def epics_to_results(epics)
 
           expected_result = epics_to_results([epic1, epic2, epic_subgroup2])
 
-          expect(subject).to eq(expected_result)
+          expect_results_are_equal(subject, expected_result)
         end
       end
     end