Add Epics to Project import/export

As Epics are Group level objects,
ImportExport::GroupProjectObjectBuilder tries to find existing one on
the Group level, and falls back to creating one if not found.

changelogs/unreleased/34867-epics_to_project_import_export.yml

+---
+title: Add epics to project import/export
+merge_request: 19883
+author:
+type: added

ee/spec/lib/ee/gitlab/import_export/project_tree_restorer_spec.rb

@@ -5,19 +5,80 @@ describe Gitlab::ImportExport::ProjectTreeRestorer do
   include ImportExport::CommonUtil
   using RSpec::Parameterized::TableSyntax
 
-  let_it_be(:project) { create(:project, :builds_disabled, :issues_disabled, name: 'project', path: 'project') }
-  let_it_be(:user) { create(:admin, username: 'user_1') }
-  let_it_be(:second_user) { create(:user, username: 'user_2' )}
   let(:shared) { project.import_export_shared }
   let(:project_tree_restorer) { described_class.new(user: user, shared: shared, project: project) }
-  let(:restored_project_json) { project_tree_restorer.restore }
 
-  before do
-    setup_import_export_config('designs', 'ee')
+  subject(:restored_project_json) { project_tree_restorer.restore }
+
+  describe 'epics' do
+    let_it_be(:user) { create(:user)}
+
+    before do
+      setup_import_export_config('group')
+    end
+
+    context 'with group' do
+      let!(:project) do
+        create(:project,
+               :builds_disabled,
+               :issues_disabled,
+               name: 'project',
+               path: 'project',
+               group: create(:group, visibility_level: Gitlab::VisibilityLevel::PRIVATE))
+      end
+
+      context 'with pre-existing epic' do
+        let!(:epic) { create(:epic, title: 'An epic', group: project.group) }
+
+        it 'associates epics' do
+          project = Project.find_by_path('project')
+
+          expect { restored_project_json }.not_to change { Epic.count }
+          expect(project.group.epics.count).to eq(1)
+          expect(project.issues.find_by_title('Issue with Epic').epic).not_to be_nil
+        end
+      end
+
+      context 'without pre-existing epic' do
+        it 'creates epic' do
+          project = Project.find_by_path('project')
+
+          expect { restored_project_json }.to change { Epic.count }.from(0).to(1)
+          expect(project.group.epics.count).to eq(1)
+          expect(project.issues.find_by_title('Issue with Epic').epic).not_to be_nil
+        end
+      end
+    end
+
+    context 'with personal namespace' do
+      let!(:project) do
+        create(:project,
+               :builds_disabled,
+               :issues_disabled,
+               name: 'project',
+               path: 'project',
+               namespace: user.namespace)
+      end
+
+      it 'ignores epic relation' do
+        project = Project.find_by_path('project')
+
+        expect { restored_project_json }.not_to change { Epic.count }
+        expect(project.import_failures.size).to eq(0)
+      end
+    end
   end
 
   describe 'restoring design management data' do
+    let_it_be(:user) { create(:admin, username: 'user_1') }
+    let_it_be(:second_user) { create(:user, username: 'user_2' )}
+    let_it_be(:project) do
+      create(:project, :builds_disabled, :issues_disabled,
+             { name: 'project', path: 'project' })
+    end
+
     before do
+      setup_import_export_config('designs', 'ee')
       restored_project_json
     end
 

ee/spec/lib/ee/gitlab/import_export/project_tree_saver_spec.rb

@@ -4,12 +4,18 @@ require 'spec_helper'
 
 describe Gitlab::ImportExport::ProjectTreeSaver do
   describe 'saves the project tree into a json object' do
-    set(:user) { create(:user) }
-    set(:project) { create(:project) }
-    set(:issue) { create(:issue, project: project) }
-    set(:design) { create(:design, :with_file, versions_count: 2, issue: issue) }
-    set(:note) { create(:diff_note_on_design, noteable: design, project: project, author: user) }
-    set(:note2) { create(:note, noteable: issue, project: project, author: user) }
+    let_it_be(:user) { create(:user) }
+    let_it_be(:group) { create(:group) }
+    let_it_be(:project) { create(:project, group: group) }
+    let_it_be(:issue) { create(:issue, project: project) }
+
+    let_it_be(:design) { create(:design, :with_file, versions_count: 2, issue: issue) }
+    let_it_be(:note) { create(:diff_note_on_design, noteable: design, project: project, author: user) }
+    let_it_be(:note2) { create(:note, noteable: issue, project: project, author: user) }
+
+    let_it_be(:epic) { create(:epic, group: group) }
+    let_it_be(:epic_issue) { create(:epic_issue, issue: issue, epic: epic) }
+
     let(:shared) { project.import_export_shared }
     let(:export_path) { "#{Dir.tmpdir}/project_tree_saver_spec_ee" }
     let(:project_tree_saver) { described_class.new(project: project, current_user: user, shared: shared) }
@@ -52,6 +58,16 @@ describe Gitlab::ImportExport::ProjectTreeSaver do
         end
       end
     end
+
+    context 'epics' do
+      it 'has issue epic' do
+        expect(saved_project_json['issues'].first['epic']).not_to be_empty
+      end
+
+      it 'has issue epic id' do
+        expect(saved_project_json['issues'].first['epic']['id']).to eql(epic.id)
+      end
+    end
   end
 
   def project_json(filename)

lib/gitlab/import_export/group_project_object_builder.rb

@@ -26,6 +26,8 @@ module Gitlab
       end
 
       def find
+        return if epic? && group.nil?
+
         find_object || klass.create(project_attributes)
       end
 
@@ -54,10 +56,10 @@ module Gitlab
       # or, if group is present:
       # `"{table_name}"."project_id" = {project.id} OR "{table_name}"."group_id" = {group.id}`
       def where_clause_base
-        clause = table[:project_id].eq(project.id) if project
-        clause = clause.or(table[:group_id].eq(group.id)) if group
-
-        clause
+        [].tap do |clauses|
+          clauses << table[:project_id].eq(project.id) if project
+          clauses << table[:group_id].eq(group.id) if group
+        end.reduce(:or)
       end
 
       # Returns Arel clause `"{table_name}"."title" = '{attributes['title']}'`
@@ -108,6 +110,10 @@ module Gitlab
         klass == MergeRequest
       end
 
+      def epic?
+        klass == Epic
+      end
+
       # If an existing group milestone used the IID
       # claim the IID back and set the group milestone to use one available
       # This is necessary to fix situations like the following:

lib/gitlab/import_export/import_export.yml

@@ -322,6 +322,13 @@ excluded_attributes:
     - :board_id
     - :label_id
     - :milestone_id
+  epic:
+    - :start_date_sourcing_milestone_id
+    - :due_date_sourcing_milestone_id
+    - :parent_id
+    - :state_id
+    - :start_date_sourcing_epic_id
+    - :due_date_sourcing_epic_id
 methods:
   notes:
     - :type
@@ -374,6 +381,7 @@ ee:
         - design_versions:
           - actions:
             - :design # Duplicate export of issues.designs in order to link the record to both Issue and Action
+        - :epic
       - protected_branches:
         - :unprotect_access_levels
       - protected_environments:

lib/gitlab/import_export/relation_factory.rb

@@ -40,7 +40,21 @@ module Gitlab
 
       IMPORTED_OBJECT_MAX_RETRIES = 5.freeze
 
-      EXISTING_OBJECT_CHECK = %i[milestone milestones label labels project_label project_labels group_label group_labels project_feature merge_request ProjectCiCdSetting container_expiration_policy].freeze
+      EXISTING_OBJECT_CHECK = %i[
+        milestone
+        milestones
+        label
+        labels
+        project_label
+        project_labels
+        group_label
+        group_labels
+        project_feature
+        merge_request
+        epic
+        ProjectCiCdSetting
+        container_expiration_policy
+      ].freeze
 
       TOKEN_RESET_MODELS = %i[Project Namespace Ci::Trigger Ci::Build Ci::Runner ProjectHook].freeze
 

lib/gitlab/import_export/relation_tree_restorer.rb

@@ -4,7 +4,7 @@ module Gitlab
   module ImportExport
     class RelationTreeRestorer
       # Relations which cannot be saved at project level (and have a group assigned)
-      GROUP_MODELS = [GroupLabel, Milestone].freeze
+      GROUP_MODELS = [GroupLabel, Milestone, Epic].freeze
 
       attr_reader :user
       attr_reader :shared

spec/fixtures/lib/gitlab/import_export/group/project.json

@@ -175,6 +175,67 @@
           }
         }
       ]
+    },
+    {
+      "id": 3,
+      "title": "Issue with Epic",
+      "author_id": 1,
+      "project_id": 8,
+      "created_at": "2019-12-08T19:41:11.233Z",
+      "updated_at": "2019-12-08T19:41:53.194Z",
+      "position": 0,
+      "branch_name": null,
+      "description": "Donec at nulla vitae sem molestie rutrum ut at sem.",
+      "state": "opened",
+      "iid": 3,
+      "updated_by_id": null,
+      "confidential": false,
+      "due_date": null,
+      "moved_to_id": null,
+      "issue_assignees": [],
+      "notes": [],
+      "milestone": {
+        "id": 2,
+        "title": "A group milestone",
+        "description": "Group-level milestone",
+        "due_date": null,
+        "created_at": "2016-06-14T15:02:04.415Z",
+        "updated_at": "2016-06-14T15:02:04.415Z",
+        "state": "active",
+        "iid": 1,
+        "group_id": 100
+      },
+      "epic": {
+        "id": 1,
+        "group_id": 5,
+        "author_id": 1,
+        "assignee_id": null,
+        "iid": 1,
+        "updated_by_id": null,
+        "last_edited_by_id": null,
+        "lock_version": 0,
+        "start_date": null,
+        "end_date": null,
+        "last_edited_at": null,
+        "created_at": "2019-12-08T19:37:07.098Z",
+        "updated_at": "2019-12-08T19:43:11.568Z",
+        "title": "An epic",
+        "description": null,
+        "start_date_sourcing_milestone_id": null,
+        "due_date_sourcing_milestone_id": null,
+        "start_date_fixed": null,
+        "due_date_fixed": null,
+        "start_date_is_fixed": null,
+        "due_date_is_fixed": null,
+        "closed_by_id": null,
+        "closed_at": null,
+        "parent_id": null,
+        "relative_position": null,
+        "state_id": "opened",
+        "start_date_sourcing_epic_id": null,
+        "due_date_sourcing_epic_id": null,
+        "milestone_id": null
+      }
     }
   ],
   "snippets": [

spec/lib/gitlab/import_export/all_models.yml

@@ -578,3 +578,30 @@ zoom_meetings:
 sentry_issue:
 - issue
 design_versions: *version
+epic:
+- subscriptions
+- award_emoji
+- description_versions
+- author
+- assignee
+- issues
+- epic_issues
+- milestone
+- notes
+- label_links
+- labels
+- todos
+- metrics
+- group
+- parent
+- children
+- updated_by
+- last_edited_by
+- closed_by
+- start_date_sourcing_milestone
+- due_date_sourcing_milestone
+- start_date_sourcing_epic
+- due_date_sourcing_epic
+- events
+- resource_label_events
+- user_mentions
\ No newline at end of file

spec/lib/gitlab/import_export/project_tree_restorer_spec.rb

@@ -502,7 +502,7 @@ describe Gitlab::ImportExport::ProjectTreeRestorer do
       end
 
       it_behaves_like 'restores project successfully',
-                      issues: 2,
+                      issues: 3,
                       labels: 2,
                       label_with_priorities: 'A project label',
                       milestones: 2,
@@ -515,7 +515,7 @@ describe Gitlab::ImportExport::ProjectTreeRestorer do
 
       it 'restores issue states' do
         expect(project.issues.with_state(:closed).count).to eq(1)
-        expect(project.issues.with_state(:opened).count).to eq(1)
+        expect(project.issues.with_state(:opened).count).to eq(2)
       end
     end
 

spec/lib/gitlab/import_export/safe_model_attributes.yml

@@ -766,3 +766,33 @@ ContainerExpirationPolicy:
 - older_than
 - keep_n
 - enabled
+Epic:
+  - id
+  - milestone_id
+  - group_id
+  - author_id
+  - assignee_id
+  - iid
+  - updated_by_id
+  - last_edited_by_id
+  - lock_version
+  - start_date
+  - end_date
+  - last_edited_at
+  - created_at
+  - updated_at
+  - title
+  - description
+  - start_date_sourcing_milestone_id
+  - due_date_sourcing_milestone_id
+  - start_date_fixed
+  - due_date_fixed
+  - start_date_is_fixed
+  - due_date_is_fixed
+  - closed_by_id
+  - closed_at
+  - parent_id
+  - relative_position
+  - state_id
+  - start_date_sourcing_epic_id
+  - due_date_sourcing_epic_id