Add destroyIteration mutation

- Add mutation
- Verify iteration can be destroyed
- Add changelog entry

Changelog: added

doc/api/graphql/reference/index.md

@@ -2562,6 +2562,25 @@ Input type: `IterationCadenceUpdateInput`
 | <a id="mutationiterationcadenceupdateerrors"></a>`errors` | [`[String!]!`](#string) | Errors encountered during execution of the mutation. |
 | <a id="mutationiterationcadenceupdateiterationcadence"></a>`iterationCadence` | [`IterationCadence`](#iterationcadence) | The updated iteration cadence. |
 
+### `Mutation.iterationDelete`
+
+Input type: `IterationDeleteInput`
+
+#### Arguments
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| <a id="mutationiterationdeleteclientmutationid"></a>`clientMutationId` | [`String`](#string) | A unique identifier for the client performing the mutation. |
+| <a id="mutationiterationdeleteid"></a>`id` | [`IterationID!`](#iterationid) | ID of the iteration. |
+
+#### Fields
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| <a id="mutationiterationdeleteclientmutationid"></a>`clientMutationId` | [`String`](#string) | A unique identifier for the client performing the mutation. |
+| <a id="mutationiterationdeleteerrors"></a>`errors` | [`[String!]!`](#string) | Errors encountered during execution of the mutation. |
+| <a id="mutationiterationdeletegroup"></a>`group` | [`Group!`](#group) | Group the iteration belongs to. |
+
 ### `Mutation.jiraImportStart`
 
 Input type: `JiraImportStartInput`

ee/app/graphql/ee/types/mutation_type.rb

@@ -25,6 +25,7 @@ module EE
         mount_mutation ::Mutations::GitlabSubscriptions::Activate
         mount_mutation ::Mutations::Iterations::Create
         mount_mutation ::Mutations::Iterations::Update
+        mount_mutation ::Mutations::Iterations::Delete
         mount_mutation ::Mutations::Iterations::Cadences::Create
         mount_mutation ::Mutations::Iterations::Cadences::Update
         mount_mutation ::Mutations::Iterations::Cadences::Destroy

ee/app/graphql/mutations/iterations/delete.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Iterations
+    class Delete < BaseMutation
+      graphql_name 'IterationDelete'
+
+      authorize :admin_iteration
+
+      argument :id, ::Types::GlobalIDType[::Iteration], required: true,
+        description: copy_field_description(Types::IterationType, :id)
+
+      field :group, ::Types::GroupType, null: false, description: 'Group the iteration belongs to.'
+
+      def resolve(id:)
+        iteration = authorized_find!(id: id)
+
+        response = ::Iterations::DeleteService.new(iteration, current_user).execute
+
+        {
+          group: response.payload[:group],
+          errors: response.errors
+        }
+      end
+
+      private
+
+      def find_object(id:)
+        # TODO: Remove coercion when working on https://gitlab.com/gitlab-org/gitlab/-/issues/257883
+        id = ::Types::GlobalIDType[::Iteration].coerce_isolated_input(id)
+        GitlabSchema.find_by_gid(id)
+      end
+    end
+  end
+end

ee/app/models/ee/iteration.rb

@@ -47,11 +47,13 @@ module EE
 
       before_validation :set_iterations_cadence, unless: -> { project_id.present? }
       before_create :set_past_iteration_state
+      before_destroy :check_if_can_be_destroyed
 
       scope :upcoming, -> { with_state(:upcoming) }
       scope :started, -> { with_state(:started) }
       scope :closed, -> { with_state(:closed) }
       scope :by_iteration_cadence_ids, ->(cadence_ids) { where(iterations_cadence_id: cadence_ids) }
+      scope :with_start_date_after, ->(date) { where('start_date > :date', date: date) }
 
       scope :within_timeframe, -> (start_date, end_date) do
         where('start_date <= ?', end_date).where('due_date >= ?', start_date)
@@ -140,6 +142,19 @@ module EE
 
     private
 
+    def last_iteration_in_cadence?
+      !::Iteration.by_iteration_cadence_ids(iterations_cadence_id).with_start_date_after(due_date).exists?
+    end
+
+    def check_if_can_be_destroyed
+      return if closed?
+
+      unless last_iteration_in_cadence?
+        errors.add(:base, "upcoming/current iterations can't be deleted unless they are the last one in the cadence")
+        throw :abort # rubocop: disable Cop/BanCatchThrow
+      end
+    end
+
     def timebox_format_reference(format = :id)
       raise ::ArgumentError, _('Unknown format') unless [:id, :name].include?(format)
 

ee/app/services/iterations/delete_service.rb

+# frozen_string_literal: true
+
+module Iterations
+  class DeleteService
+    include Gitlab::Allowable
+
+    def initialize(iteration, user)
+      @iteration = iteration
+      @group = iteration.group
+      @current_user = user
+    end
+
+    def execute
+      response_payload = { group: @group }
+      return ::ServiceResponse.error(message: _('Operation not allowed'), payload: response_payload, http_status: 403) unless can_delete_iteration?
+
+      if delete_and_remove_references
+        ::ServiceResponse.success(payload: response_payload)
+      else
+        ::ServiceResponse.error(message: iteration.errors.full_messages, payload: response_payload, http_status: 422)
+      end
+    end
+
+    private
+
+    attr_reader :iteration, :current_user, :group
+
+    def can_delete_iteration?
+      group.licensed_feature_available?(:iterations) &&
+        can?(current_user, :admin_iteration, iteration)
+    end
+
+    def delete_and_remove_references
+      ApplicationRecord.transaction do
+        if Board.in_iterations(iteration).update_all(iteration_id: nil) && iteration.destroy
+          true
+        else
+          raise ActiveRecord::Rollback
+        end
+      end
+    end
+  end
+end

ee/changelogs/unreleased/292268-destroy-iteration-mutation.yml

+---
+title: Add support to destroy iterations in GraphQL
+merge_request: 60655
+author:
+type: added

ee/spec/requests/api/graphql/mutations/iterations/delete_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Deleting an iteration' do
+  include GraphqlHelpers
+
+  let_it_be(:current_user) { create(:user) }
+  let_it_be(:group) { create(:group) }
+  let_it_be(:iteration, refind: true) { create(:iteration, group: group) }
+
+  let(:params) do
+    { id: iteration.to_global_id.to_s }
+  end
+
+  let(:mutation) do
+    graphql_mutation(:iteration_delete, params)
+  end
+
+  def mutation_response
+    graphql_mutation_response(:iteration_delete)
+  end
+
+  context 'when the user does not have permission' do
+    before do
+      stub_licensed_features(iterations: true)
+    end
+
+    it_behaves_like 'a mutation that returns a top-level access error'
+  end
+
+  context 'when the user has permission' do
+    before do
+      group.add_developer(current_user)
+    end
+
+    context 'when iterations feature is disabled' do
+      before do
+        stub_licensed_features(iterations: false)
+      end
+
+      it_behaves_like 'a mutation that returns top-level errors', errors: [
+        'The resource that you are attempting to access does not exist or you don\'t have permission to ' \
+        'perform this action'
+      ]
+    end
+
+    context 'when iterations feature is enabled' do
+      before do
+        stub_licensed_features(iterations: true)
+      end
+
+      it 'deletes the iteration', :aggregate_failures do
+        expect do
+          post_graphql_mutation(mutation, current_user: current_user)
+        end.to change(Iteration, :count).by(-1)
+
+        expect(mutation_response).to include('group' => hash_including('id' => group.to_global_id.to_s))
+      end
+
+      context 'when required arguments are missing' do
+        let(:params) { {} }
+
+        it 'returns error about required argument' do
+          post_graphql_mutation(mutation, current_user: current_user)
+
+          expect_graphql_errors_to_include(/was provided invalid value for id \(Expected value to not be null\)/)
+        end
+      end
+    end
+  end
+end

ee/spec/services/iterations/delete_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Iterations::DeleteService do
+  subject(:results) { described_class.new(iteration_to_delete, user).execute }
+
+  let_it_be(:group, refind: true) { create(:group) }
+  let_it_be(:project) { create(:project, :repository, group: group) }
+  let_it_be(:user) { create(:user) }
+  let_it_be(:start_date) { 3.weeks.ago }
+  let_it_be(:iteration_cadence1) { create(:iterations_cadence, group: group, start_date: start_date, duration_in_weeks: 1, iterations_in_advance: 2) }
+  let_it_be(:iteration_cadence2) { create(:iterations_cadence, group: group, start_date: start_date, duration_in_weeks: 1, iterations_in_advance: 2) }
+
+  let_it_be(:past_iteration, refind: true) { create(:closed_iteration, iterations_cadence: iteration_cadence1, group: group, start_date: start_date, due_date: start_date + 13.days) }
+  let_it_be(:past_board, refind: true) { create(:board, iteration: past_iteration, group: group) }
+  let_it_be(:past_issue, refind: true) { create(:issue, namespace: group, iteration: past_iteration) }
+  let_it_be(:past_merge_request, refind: true) { create(:merge_request, source_project: project, iteration: past_iteration) }
+
+  let_it_be(:current_iteration, refind: true) { create(:started_iteration, iterations_cadence: iteration_cadence1, group: group, start_date: start_date + 14.days, due_date: start_date + 27.days) }
+
+  let_it_be(:future_iteration, refind: true) { create(:upcoming_iteration, iterations_cadence: iteration_cadence1, group: group, start_date: start_date + 28.days, due_date: start_date + 41.days) }
+
+  let_it_be(:last_future_iteration, refind: true) { create(:upcoming_iteration, iterations_cadence: iteration_cadence1, group: group, start_date: start_date + 42.days, due_date: start_date + 55.days) }
+  let_it_be(:last_future_board, refind: true) { create(:board, iteration: last_future_iteration, group: group) }
+  let_it_be(:last_future_issue, refind: true) { create(:issue, namespace: group, iteration: last_future_iteration) }
+  let_it_be(:last_future_merge_request, refind: true) { create(:merge_request, source_branch: 'another-feature', source_project: project, iteration: last_future_iteration) }
+
+  let_it_be(:other_cadence_iteration, refind: true) { create(:started_iteration, iterations_cadence: iteration_cadence2, group: group, start_date: start_date + 14.days, due_date: start_date + 27.days) }
+  let_it_be(:other_cadence_board, refind: true) { create(:board, iteration: other_cadence_iteration, group: group) }
+  let_it_be(:other_cadence_issue, refind: true) { create(:issue, namespace: group, iteration: other_cadence_iteration) }
+  let_it_be(:other_cadence_merge_request, refind: true) { create(:merge_request, source_branch: 'another-feature2', source_project: project, iteration: other_cadence_iteration) }
+
+  let(:iteration_to_delete) { past_iteration }
+
+  RSpec.shared_examples 'iteration delete fails with message' do |message:|
+    it { is_expected.to be_error }
+
+    it 'returns not allowed message' do
+      expect(results.message).to eq(message)
+    end
+
+    it 'returns the iteration group as part of the response' do
+      expect(results.payload[:group]).to eq(group)
+    end
+  end
+
+  RSpec.shared_examples 'successfully deletes an iteration' do
+    it { is_expected.to be_success }
+
+    it 'deletes the iteration and associated records' do
+      expect do
+        results
+
+        associated_board.reload
+        associated_issue.reload
+        associated_mr.reload
+      end.to change(Iteration, :count).by(-1).and(
+        change(List, :count).by(-1)
+      ).and(
+        change(ResourceIterationEvent, :count).by(-1)
+      ).and(
+        change(Iteration, :count).by(-1)
+      ).and(
+        change(associated_board, :iteration_id).from(iteration_to_delete.id).to(nil)
+      ).and(
+        change(associated_issue, :iteration).from(iteration_to_delete).to(nil)
+      ).and(
+        change(associated_mr, :iteration).from(iteration_to_delete).to(nil)
+      )
+    end
+
+    it 'returns the iteration group as part of the response' do
+      expect(results.payload[:group]).to eq(group)
+    end
+  end
+
+  before(:all) do
+    create(:iteration_list, iteration: past_iteration)
+    create(:resource_iteration_event, iteration: past_iteration)
+    create(:iteration_list, iteration: last_future_iteration)
+    create(:resource_iteration_event, iteration: last_future_iteration)
+    create(:iteration_list, iteration: other_cadence_iteration)
+    create(:resource_iteration_event, iteration: other_cadence_iteration)
+  end
+
+  describe '#execute' do
+    context 'when iterations feature enabled' do
+      before do
+        stub_licensed_features(iterations: true)
+      end
+
+      context 'when user is authorized' do
+        before do
+          group.add_developer(user)
+        end
+
+        context 'when deleting a past iteration' do
+          let(:iteration_to_delete) { past_iteration }
+          let(:associated_mr) { past_merge_request }
+          let(:associated_issue) { past_issue }
+          let(:associated_board) { past_board }
+
+          it_behaves_like 'successfully deletes an iteration'
+        end
+
+        context 'when deleting the current iteration' do
+          let(:iteration_to_delete) { current_iteration }
+
+          it_behaves_like 'iteration delete fails with message', message: ["upcoming/current iterations can't be deleted unless they are the last one in the cadence"]
+        end
+
+        context 'when deleting a future iteration that is not the last one' do
+          let(:iteration_to_delete) { future_iteration }
+
+          it_behaves_like 'iteration delete fails with message', message: ["upcoming/current iterations can't be deleted unless they are the last one in the cadence"]
+        end
+
+        context 'when deleting the last future iteration' do
+          let(:iteration_to_delete) { last_future_iteration }
+          let(:associated_mr) { last_future_merge_request }
+          let(:associated_issue) { last_future_issue }
+          let(:associated_board) { last_future_board }
+
+          it_behaves_like 'successfully deletes an iteration'
+        end
+
+        context 'when deleting the current iteration in another cadence' do
+          let(:iteration_to_delete) { other_cadence_iteration }
+          let(:associated_mr) { other_cadence_merge_request }
+          let(:associated_issue) { other_cadence_issue }
+          let(:associated_board) { other_cadence_board }
+
+          it_behaves_like 'successfully deletes an iteration'
+        end
+      end
+
+      context 'when user is not authorized' do
+        it_behaves_like 'iteration delete fails with message', message: 'Operation not allowed'
+      end
+    end
+
+    context 'when iterations feature disabled' do
+      before do
+        stub_licensed_features(iterations: false)
+      end
+
+      context 'when user is authorized' do
+        before do
+          group.add_developer(user)
+        end
+
+        it_behaves_like 'iteration delete fails with message', message: 'Operation not allowed'
+      end
+
+      context 'when user is not authorized' do
+        it_behaves_like 'iteration delete fails with message', message: 'Operation not allowed'
+      end
+    end
+  end
+end