Add copy_metadata quick action

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18497

app/services/quick_actions/interpret_service.rb

@@ -269,6 +269,26 @@ module QuickActions
       end
     end
 
+    desc 'Copy labels and milestone from other issue or merge request'
+    explanation do |source_issuable|
+      "Copy labels and milestone from #{source_issuable.to_reference}."
+    end
+    params '#issue | !merge_request'
+    condition do
+      issuable.persisted? &&
+        current_user.can?(:"update_#{issuable.to_ability_name}", issuable)
+    end
+    parse_params do |issuable_param|
+      extract_references(issuable_param, :issue).first ||
+        extract_references(issuable_param, :merge_request).first
+    end
+    command :copy_metadata do |source_issuable|
+      if source_issuable.present? && source_issuable.project.id == issuable.project.id
+        @updates[:add_label_ids] = source_issuable.labels.map(&:id)
+        @updates[:milestone_id] = source_issuable.milestone.id if source_issuable.milestone
+      end
+    end
+
     desc 'Add a todo'
     explanation 'Adds a todo.'
     condition do

changelogs/unreleased/add-copy-metadata-command.yml

+---
+title: Add Copy metadata quick action
+merge_request: 16473
+author: Mateusz Bajorski
+type: added

doc/user/project/quick_actions.md

@@ -44,6 +44,7 @@ do.
 | `/move path/to/project`    | Moves issue to another project |
 | `/tableflip`               | Append the comment with `(╯°□°)╯︵ ┻━┻` |
 | `/shrug`                   | Append the comment with `¯\＿(ツ)＿/¯` |
+| <code>/copy_metadata #issue &#124; !merge_request</code> | Copy labels and milestone from other issue or merge request |
 
 Note: In GitLab Starter every issue can have more than one assignee, so commands `/assign`, `/unassign` and `/reassign`
 support multiple assignees.

spec/services/quick_actions/interpret_service_spec.rb

+# coding: utf-8
 require 'spec_helper'
 
 describe QuickActions::InterpretService do
@@ -325,6 +326,23 @@ describe QuickActions::InterpretService do
       end
     end
 
+    shared_examples 'copy_metadata command' do
+      it 'fetches issue or merge request and copies labels and milestone if content contains /copy_metadata reference' do
+        source_issuable # populate the issue
+        todo_label # populate this label
+        inreview_label # populate this label
+        _, updates = service.execute(content, issuable)
+
+        expect(updates[:add_label_ids]).to match_array([inreview_label.id, todo_label.id])
+
+        if source_issuable.milestone
+          expect(updates[:milestone_id]).to eq(source_issuable.milestone.id)
+        else
+          expect(updates).not_to have_key(:milestone_id)
+        end
+      end
+    end
+
     shared_examples 'shrug command' do
       it 'appends ¯\_(ツ)_/¯ to the comment' do
         new_content, _ = service.execute(content, issuable)
@@ -833,6 +851,65 @@ describe QuickActions::InterpretService do
       end
     end
 
+    context '/copy_metadata command' do
+      let(:todo_label) { create(:label, project: project, title: 'To Do') }
+      let(:inreview_label) { create(:label, project: project, title: 'In Review') }
+
+      it_behaves_like 'empty command' do
+        let(:content) { '/copy_metadata' }
+        let(:issuable) { issue }
+      end
+
+      it_behaves_like 'copy_metadata command' do
+        let(:source_issuable) { create(:labeled_issue, project: project, labels: [inreview_label, todo_label]) }
+
+        let(:content) { "/copy_metadata #{source_issuable.to_reference}" }
+        let(:issuable) { issue }
+      end
+
+      context 'when the parent issuable has a milestone' do
+        it_behaves_like 'copy_metadata command' do
+          let(:source_issuable) { create(:labeled_issue, project: project, labels: [todo_label, inreview_label], milestone: milestone) }
+
+          let(:content) { "/copy_metadata #{source_issuable.to_reference(project)}" }
+          let(:issuable) { issue }
+        end
+      end
+
+      context 'when more than one issuable is passed' do
+        it_behaves_like 'copy_metadata command' do
+          let(:source_issuable) { create(:labeled_issue, project: project, labels: [inreview_label, todo_label]) }
+          let(:other_label) { create(:label, project: project, title: 'Other') }
+          let(:other_source_issuable) { create(:labeled_issue, project: project, labels: [other_label]) }
+
+          let(:content) { "/copy_metadata #{source_issuable.to_reference} #{other_source_issuable.to_reference}" }
+          let(:issuable) { issue }
+        end
+      end
+
+      context 'cross project references' do
+        it_behaves_like 'empty command' do
+          let(:other_project) { create(:project, :public) }
+          let(:source_issuable) { create(:labeled_issue, project: other_project, labels: [todo_label, inreview_label]) }
+          let(:content) { "/copy_metadata #{source_issuable.to_reference(project)}" }
+          let(:issuable) { issue }
+        end
+
+        it_behaves_like 'empty command' do
+          let(:content) { "/copy_metadata imaginary#1234" }
+          let(:issuable) { issue }
+        end
+
+        it_behaves_like 'empty command' do
+          let(:other_project) { create(:project, :private) }
+          let(:source_issuable) { create(:issue, project: other_project) }
+
+          let(:content) { "/copy_metadata #{source_issuable.to_reference(project)}" }
+          let(:issuable) { issue }
+        end
+      end
+    end
+
     context '/duplicate command' do
       it_behaves_like 'duplicate command' do
         let(:issue_duplicate) { create(:issue, project: project) }