Added slash command to close an issue as a duplicate. Closes #26372

4 files changed, 158 insertions, 0 deletions

diff --git a/spec/features/issues/user_uses_slash_commands_spec.rb b/spec/features/issues/user_uses_slash_commands_spec.rb
index 1cd1f016674..d5de060b033 100644
--- a/spec/features/issues/user_uses_slash_commands_spec.rb
+++ b/spec/features/issues/user_uses_slash_commands_spec.rb
@@ -134,5 +134,46 @@ feature 'Issues > User uses quick actions', feature: true, js: true do
         expect(page).not_to have_content '/wip'
       end
     end
+
+    describe 'mark issue as duplicate' do
+      let(:issue) { create(:issue, project: project) }
+      let(:original_issue) { create(:issue, project: project) }
+
+      context 'when the current user can update issues' do
+        it 'does not create a note, and marks the issue as a duplicate' do
+          write_note("/duplicate ##{original_issue.to_reference}")
+
+          expect(page).not_to have_content "/duplicate #{original_issue.to_reference}"
+          expect(page).to have_content 'Commands applied'
+          expect(page).to have_content "marked this issue as a duplicate of #{original_issue.to_reference}"
+
+          issue.reload
+
+          expect(issue.closed?).to be_truthy
+        end
+      end
+
+      context 'when the current user cannot update the issue' do
+        let(:guest) { create(:user) }
+        before do
+          project.team << [guest, :guest]
+          logout
+          login_with(guest)
+          visit namespace_project_issue_path(project.namespace, project, issue)
+        end
+
+        it 'does not create a note, and does not mark the issue as a duplicate' do
+          write_note("/duplicate ##{original_issue.to_reference}")
+
+          expect(page).to have_content "/duplicate ##{original_issue.to_reference}"
+          expect(page).not_to have_content 'Commands applied'
+          expect(page).not_to have_content "marked this issue as a duplicate of #{original_issue.to_reference}"
+
+          issue.reload
+
+          expect(issue.closed?).to be_falsey
+        end
+      end
+    end
   end
 end
diff --git a/spec/services/issues/update_service_spec.rb b/spec/services/issues/update_service_spec.rb
index d0b991f19ab..3e7abf85106 100644
--- a/spec/services/issues/update_service_spec.rb
+++ b/spec/services/issues/update_service_spec.rb
@@ -491,6 +491,62 @@ describe Issues::UpdateService, services: true do
       include_examples 'updating mentions', Issues::UpdateService
     end
 
+    context 'duplicate issue' do
+      let(:issues_finder) { spy(:issues_finder) }
+      let(:close_service) { spy(:close_service) }
+
+      before do
+        allow(IssuesFinder).to receive(:new).and_return(issues_finder)
+        allow(Issues::CloseService).to receive(:new).and_return(close_service)
+        allow(SystemNoteService).to receive(:cross_reference)
+        allow(SystemNoteService).to receive(:mark_duplicate_issue)
+      end
+
+      context 'invalid original_issue_id' do
+        let(:original_issue_id) { double }
+        before { update_issue({ original_issue_id: original_issue_id }) }
+
+        it 'finds the root issue' do
+          expect(issues_finder).to have_received(:find).with(original_issue_id)
+        end
+
+        it 'does not close the issue' do
+          expect(close_service).not_to have_received(:execute)
+        end
+
+        it 'does not create system notes' do
+          expect(SystemNoteService).not_to have_received(:cross_reference)
+          expect(SystemNoteService).not_to have_received(:mark_duplicate_issue)
+        end
+      end
+
+      context 'valid original_issue_id' do
+        let(:original_issue) { create(:issue, project: project) }
+        let(:original_issue_id) { double }
+
+        before do
+          allow(issues_finder).to receive(:find).and_return(original_issue)
+          update_issue({ original_issue_id: original_issue_id })
+        end
+
+        it 'finds the root issue' do
+          expect(issues_finder).to have_received(:find).with(original_issue_id)
+        end
+
+        it 'closes the issue' do
+          expect(close_service).to have_received(:execute).with(issue)
+        end
+
+        it 'creates a system note that this issue is a duplicate' do
+          expect(SystemNoteService).to have_received(:mark_duplicate_issue).with(issue, project, user, original_issue)
+        end
+
+        it 'creates a cross reference system note in the other issue' do
+          expect(SystemNoteService).to have_received(:cross_reference).with(original_issue, issue, user)
+        end
+      end
+    end
+
     include_examples 'issuable update service' do
       let(:open_issuable) { issue }
       let(:closed_issuable) { create(:closed_issue, project: project) }
diff --git a/spec/services/quick_actions/interpret_service_spec.rb b/spec/services/quick_actions/interpret_service_spec.rb
index a2db3f68ff7..3e4aa66756c 100644
--- a/spec/services/quick_actions/interpret_service_spec.rb
+++ b/spec/services/quick_actions/interpret_service_spec.rb
@@ -261,6 +261,17 @@ describe QuickActions::InterpretService, services: true do
       end
     end
 
+    shared_examples 'duplicate command' do
+      let(:issue_duplicate) { create(:issue, project: project) }
+
+      it 'fetches issue and populates original_issue_id if content contains /duplicate issue_reference' do
+        issue_duplicate # populate the issue
+        _, updates = service.execute(content, issuable)
+
+        expect(updates).to eq(original_issue_id: issue_duplicate.id)
+      end
+    end
+
     it_behaves_like 'reopen command' do
       let(:content) { '/reopen' }
       let(:issuable) { issue }
@@ -644,6 +655,26 @@ describe QuickActions::InterpretService, services: true do
       let(:issuable) { issue }
     end
 
+    it_behaves_like 'duplicate command' do
+      let(:content) { "/duplicate #{issue_duplicate.to_reference}" }
+      let(:issuable) { issue }
+    end
+
+    it_behaves_like 'empty command' do
+      let(:content) { '/duplicate #{issue.to_reference}' }
+      let(:issuable) { issue }
+    end
+
+    it_behaves_like 'empty command' do
+      let(:content) { '/duplicate' }
+      let(:issuable) { issue }
+    end
+
+    it_behaves_like 'empty command' do
+      let(:content) { '/duplicate imaginary#1234' }
+      let(:issuable) { issue }
+    end
+
     context 'when current_user cannot :admin_issue' do
       let(:visitor) { create(:user) }
       let(:issue) { create(:issue, project: project, author: visitor) }
@@ -693,6 +724,11 @@ describe QuickActions::InterpretService, services: true do
         let(:content) { '/remove_due_date' }
         let(:issuable) { issue }
       end
+
+      it_behaves_like 'empty command' do
+        let(:content) { '/duplicate #{issue.to_reference}' }
+        let(:issuable) { issue }
+      end
     end
 
     context '/award command' do
diff --git a/spec/services/system_note_service_spec.rb b/spec/services/system_note_service_spec.rb
index 60477b8e9ba..db120889119 100644
--- a/spec/services/system_note_service_spec.rb
+++ b/spec/services/system_note_service_spec.rb
@@ -1101,4 +1101,29 @@ describe SystemNoteService, services: true do
       expect(subject.note).to include(diffs_project_merge_request_url(project, merge_request, diff_id: diff_id, anchor: line_code))
     end
   end
+
+  describe '.mark_duplicate_issue' do
+    subject { described_class.mark_duplicate_issue(noteable, project, author, original_issue) }
+
+    context 'within the same project' do
+      let(:original_issue) { create(:issue, project: project) }
+
+      it_behaves_like 'a system note' do
+        let(:action) { 'duplicate' }
+      end
+
+      it { expect(subject.note).to eq "marked this issue as a duplicate of #{original_issue.to_reference}" }
+    end
+
+    context 'across different projects' do
+      let(:other_project)  { create(:empty_project) }
+      let(:original_issue) { create(:issue, project: other_project) }
+
+      it_behaves_like 'a system note' do
+        let(:action) { 'duplicate' }
+      end
+
+      it { expect(subject.note).to eq "marked this issue as a duplicate of #{original_issue.to_reference(project)}" }
+    end
+  end
 end