Support iteration filters in issues API

This is required for vue_issuables_list because it uses the API to query
the issues

app/assets/javascripts/filtered_search/dropdown_ajax_filter.js

@@ -22,7 +22,7 @@ export default class DropdownAjaxFilter extends FilteredSearchDropdown {
 
   ajaxFilterConfig() {
     return {
-      endpoint: `${gon.relative_url_root || ''}${this.endpoint}`,
+      endpoint: this.endpoint,
       searchKey: 'search',
       searchValueFunction: this.getSearchInput.bind(this),
       loadingTemplate: this.loadingTemplate,
@@ -33,9 +33,11 @@ export default class DropdownAjaxFilter extends FilteredSearchDropdown {
   }
 
   itemClicked(e) {
-    super.itemClicked(e, selected =>
-      selected.querySelector('.dropdown-light-content').innerText.trim(),
-    );
+    super.itemClicked(e, selected => {
+      const title = selected.querySelector('.dropdown-light-content').innerText.trim();
+
+      return DropdownUtils.getEscapedText(title);
+    });
   }
 
   renderContent(forceShowList = false) {

app/assets/javascripts/filtered_search/dropdown_user.js

@@ -5,7 +5,7 @@ export default class DropdownUser extends DropdownAjaxFilter {
   constructor(options = {}) {
     super({
       ...options,
-      endpoint: '/-/autocomplete/users.json',
+      endpoint: `${gon.relative_url_root || ''}/-/autocomplete/users.json`,
       symbol: '@',
     });
   }

app/assets/javascripts/filtered_search/filtered_search_dropdown_manager.js

@@ -12,6 +12,7 @@ export default class FilteredSearchDropdownManager {
     runnerTagsEndpoint = '',
     labelsEndpoint = '',
     milestonesEndpoint = '',
+    iterationsEndpoint = '',
     releasesEndpoint = '',
     environmentsEndpoint = '',
     epicsEndpoint = '',
@@ -28,6 +29,7 @@ export default class FilteredSearchDropdownManager {
     this.runnerTagsEndpoint = removeTrailingSlash(runnerTagsEndpoint);
     this.labelsEndpoint = removeTrailingSlash(labelsEndpoint);
     this.milestonesEndpoint = removeTrailingSlash(milestonesEndpoint);
+    this.iterationsEndpoint = removeTrailingSlash(iterationsEndpoint);
     this.releasesEndpoint = removeTrailingSlash(releasesEndpoint);
     this.epicsEndpoint = removeTrailingSlash(epicsEndpoint);
     this.environmentsEndpoint = removeTrailingSlash(environmentsEndpoint);

app/assets/javascripts/filtered_search/filtered_search_manager.js

@@ -52,16 +52,24 @@ export default class FilteredSearchManager {
     this.placeholder = placeholder;
     this.anchor = anchor;
 
-    const { multipleAssignees } = this.filteredSearchInput.dataset;
+    const {
+      multipleAssignees,
+      epicsEndpoint,
+      iterationsEndpoint,
+    } = this.filteredSearchInput.dataset;
+
     if (multipleAssignees && this.filteredSearchTokenKeys.enableMultipleAssignees) {
       this.filteredSearchTokenKeys.enableMultipleAssignees();
     }
 
-    const { epicsEndpoint } = this.filteredSearchInput.dataset;
     if (!epicsEndpoint && this.filteredSearchTokenKeys.removeEpicToken) {
       this.filteredSearchTokenKeys.removeEpicToken();
     }
 
+    if (!iterationsEndpoint && this.filteredSearchTokenKeys.removeIterationToken) {
+      this.filteredSearchTokenKeys.removeIterationToken();
+    }
+
     this.recentSearchesStore = new RecentSearchesStore({
       isLocalStorageAvailable: RecentSearchesService.isAvailable(),
       allowedKeys: this.filteredSearchTokenKeys.getKeys(),
@@ -112,6 +120,7 @@ export default class FilteredSearchManager {
         releasesEndpoint = '',
         environmentsEndpoint = '',
         epicsEndpoint = '',
+        iterationsEndpoint = '',
       } = this.filteredSearchInput.dataset;
 
       this.dropdownManager = new FilteredSearchDropdownManager({
@@ -121,6 +130,7 @@ export default class FilteredSearchManager {
         releasesEndpoint,
         environmentsEndpoint,
         epicsEndpoint,
+        iterationsEndpoint,
         tokenizer: this.tokenizer,
         page: this.page,
         isGroup: this.isGroup,

app/views/shared/issuable/_search_bar.html.haml

@@ -96,6 +96,7 @@
                   %li.filter-dropdown-item
                     %button.btn.btn-link.js-data-value{ type: 'button' }
                       {{title}}
+              = render_if_exists 'shared/issuable/filter_iteration', type: type
               #js-dropdown-release.filtered-search-input-dropdown-menu.dropdown-menu
                 %ul{ data: { dropdown: true } }
                   %li.filter-dropdown-item{ data: { value: 'None' } }

doc/api/issues.md

@@ -60,6 +60,9 @@ GET /issues?state=opened
 | `due_date`          | string           | no         | Return issues that have no due date (`0`) or whose due date is this week, this month, between two weeks ago and next month, or which are overdue. Accepts: `0` (no due date), `overdue`, `week`, `month`, `next_month_and_previous_two_weeks`. _(Introduced in [GitLab 13.3](https://gitlab.com/gitlab-org/gitlab/-/issues/233420))_ |
 | `iids[]`            | integer array    | no         | Return only the issues having the given `iid`                                                                                                       |
 | `in`                | string           | no         | Modify the scope of the `search` attribute. `title`, `description`, or a string joining them with comma. Default is `title,description`             |
+| `iteration_id` **(STARTER)** | integer | no         | Return issues assigned to the given iteration ID. `None` returns issues that do not belong to an iteration. `Any` returns issues that belong to an iteration. Mutually exclusive with `iteration_title`. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/118742) in [GitLab Starter](https://about.gitlab.com/pricing/) 13.6)_ |
+| `iteration_title` **(STARTER)** | string | no       | Return issues assigned to the iteration with the given title. Similar to `iteration_id` and mutually exclusive with `iteration_id`. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/118742) in [GitLab Starter](https://about.gitlab.com/pricing/) 13.6)_ |
+| `milestone`         | string           | no         | The milestone title. `None` lists all issues with no milestone. `Any` lists all issues that have an assigned milestone.                             |
 | `labels`            | string           | no         | Comma-separated list of label names, issues must have all labels to be returned. `None` lists all issues with no labels. `Any` lists all issues with at least one label. `No+Label` (Deprecated) lists all issues with no labels. Predefined names are case-insensitive. |
 | `milestone`         | string           | no         | The milestone title. `None` lists all issues with no milestone. `Any` lists all issues that have an assigned milestone.                             |
 | `my_reaction_emoji` | string           | no         | Return issues reacted by the authenticated user by the given `emoji`. `None` returns issues not given a reaction. `Any` returns issues given at least one reaction. _([Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/14016) in GitLab 10.0)_ |

ee/app/assets/javascripts/filtered_search/available_dropdown_mappings.js

 import DropdownUser from '~/filtered_search/dropdown_user';
 import DropdownNonUser from '~/filtered_search/dropdown_non_user';
 import DropdownWeight from './dropdown_weight';
+import DropdownAjaxFilter from '~/filtered_search/dropdown_ajax_filter';
 import AvailableDropdownMappingsCE from '~/filtered_search/available_dropdown_mappings';
 
 export default class AvailableDropdownMappings {
@@ -9,6 +10,7 @@ export default class AvailableDropdownMappings {
     runnerTagsEndpoint,
     labelsEndpoint,
     milestonesEndpoint,
+    iterationsEndpoint,
     epicsEndpoint,
     releasesEndpoint,
     environmentsEndpoint,
@@ -20,6 +22,7 @@ export default class AvailableDropdownMappings {
     this.runnerTagsEndpoint = runnerTagsEndpoint;
     this.labelsEndpoint = labelsEndpoint;
     this.milestonesEndpoint = milestonesEndpoint;
+    this.iterationsEndpoint = iterationsEndpoint;
     this.epicsEndpoint = epicsEndpoint;
     this.releasesEndpoint = releasesEndpoint;
     this.environmentsEndpoint = environmentsEndpoint;
@@ -65,6 +68,16 @@ export default class AvailableDropdownMappings {
       element: this.container.querySelector('#js-dropdown-epic'),
     };
 
+    ceMappings.iteration = {
+      reference: null,
+      gl: DropdownAjaxFilter,
+      extraArguments: {
+        endpoint: this.iterationsEndpoint,
+        symbol: '',
+      },
+      element: this.container.querySelector('#js-dropdown-iteration'),
+    };
+
     return this.ceAvailableMappings.buildMappings(supportedTokens, ceMappings);
   }
 

ee/app/assets/javascripts/filtered_search/issuable_filtered_search_token_keys.js

@@ -25,6 +25,15 @@ export const epicTokenKey = {
   icon: 'epic',
 };
 
+export const iterationTokenKey = {
+  formattedKey: __('Iteration'),
+  key: 'iteration',
+  type: 'string',
+  param: 'title',
+  symbol: '',
+  icon: 'iteration',
+};
+
 export const weightConditions = [
   {
     url: 'weight=None',
@@ -79,15 +88,34 @@ export const epicConditions = [
   },
 ];
 
+export const iterationConditions = [
+  {
+    url: 'iteration_id=None',
+    operator: '=',
+    tokenKey: 'iteration',
+    value: __('None'),
+  },
+  {
+    url: 'iteration_id=Any',
+    operator: '=',
+    tokenKey: 'iteration',
+    value: __('Any'),
+  },
+];
+
 /**
  * Filter tokens for issues in EE.
  */
 class IssuesFilteredSearchTokenKeysEE extends FilteredSearchTokenKeys {
   constructor() {
+    const milestoneTokenKeyIndex = tokenKeys.findIndex(tk => tk.key === 'milestone');
+    tokenKeys.splice(milestoneTokenKeyIndex + 1, 0, iterationTokenKey);
+
     super([...tokenKeys, epicTokenKey, weightTokenKey], alternativeTokenKeys, [
       ...conditions,
       ...weightConditions,
       ...epicConditions,
+      ...iterationConditions,
     ]);
   }
 
@@ -105,7 +133,15 @@ class IssuesFilteredSearchTokenKeysEE extends FilteredSearchTokenKeys {
   }
 
   removeEpicToken() {
-    const index = this.tokenKeys.findIndex(token => token.key === epicTokenKey.key);
+    this.removeToken(epicTokenKey);
+  }
+
+  removeIterationToken() {
+    this.removeToken(iterationTokenKey);
+  }
+
+  removeToken(tokenKey) {
+    const index = this.tokenKeys.findIndex(token => token.key === tokenKey.key);
     if (index >= 0) {
       this.tokenKeys.splice(index, 1);
     }

ee/app/finders/ee/issues_finder.rb

@@ -11,7 +11,12 @@ module EE
 
       override :scalar_params
       def scalar_params
-        @scalar_params ||= super + [:weight, :epic_id, :include_subepics]
+        @scalar_params ||= super + [:weight, :epic_id, :include_subepics, :iteration_id, :iteration_title]
+      end
+
+      override :negatable_params
+      def negatable_params
+        @negatable_params ||= super + [:iteration_title]
       end
     end
 
@@ -64,21 +69,23 @@ module EE
     end
 
     def by_iteration(items)
-      return items unless params.iterations
+      return items unless params.by_iteration?
 
-      case params.iterations.to_s.downcase
-      when ::IssuableFinder::Params::FILTER_NONE
+      if params.filter_by_no_iteration?
         items.no_iteration
-      when ::IssuableFinder::Params::FILTER_ANY
+      elsif params.filter_by_any_iteration?
         items.any_iteration
+      elsif params.filter_by_iteration_title?
+        items.with_iteration_title(params[:iteration_title])
       else
-        items.in_iterations(params.iterations)
+        items.in_iterations(params[:iteration_id])
       end
     end
 
     override :filter_negated_items
     def filter_negated_items(items)
       items = by_negated_epic(items)
+      items = by_negated_iteration(items)
 
       super(items)
     end
@@ -88,5 +95,11 @@ module EE
 
       items.not_in_epics(not_params[:epic_id].to_i)
     end
+
+    def by_negated_iteration(items)
+      return items unless not_params[:iteration_title].present?
+
+      items.without_iteration_title(not_params[:iteration_title])
+    end
   end
 end

ee/app/finders/ee/issues_finder/params.rb

@@ -51,8 +51,20 @@ module EE
         end
       end
 
-      def iterations
-        params[:iteration_id]
+      def by_iteration?
+        params[:iteration_id].present? || params[:iteration_title].present?
+      end
+
+      def filter_by_no_iteration?
+        params[:iteration_id].to_s.downcase == ::IssuableFinder::Params::FILTER_NONE
+      end
+
+      def filter_by_any_iteration?
+        params[:iteration_id].to_s.downcase == ::IssuableFinder::Params::FILTER_ANY
+      end
+
+      def filter_by_iteration_title?
+        params[:iteration_title].present?
       end
     end
   end

ee/app/helpers/ee/search_helper.rb

@@ -17,6 +17,14 @@ module EE
         options[:data]['epics-endpoint'] = group_epics_path(@group)
       end
 
+      if allow_filtering_by_iteration?
+        if @project
+          options[:data]['iterations-endpoint'] = expose_path(api_v4_projects_iterations_path(id: @project.id))
+        elsif @group
+          options[:data]['iterations-endpoint'] = expose_path(api_v4_groups_iterations_path(id: @group.id))
+        end
+      end
+
       options
     end
 
@@ -131,6 +139,16 @@ module EE
         context.feature_available?(:multiple_issue_assignees))
     end
 
+    def allow_filtering_by_iteration?
+      # We currently only have group-level iterations so we hide
+      # this filter for projects under personal namespaces
+      return false if @project && @project.namespace.user?
+
+      context = @project.presence || @group.presence
+
+      context && ::Feature.enabled?(:filter_bar_iterations, context) && context.feature_available?(:iterations)
+    end
+
     def gitlab_com_snippet_db_search?
       @current_user &&
         @show_snippets &&

ee/app/models/ee/issue.rb

@@ -32,6 +32,8 @@ module EE
       scope :no_iteration, -> { where(sprint_id: nil) }
       scope :any_iteration, -> { where.not(sprint_id: nil) }
       scope :in_iterations, ->(iterations) { where(sprint_id: iterations) }
+      scope :with_iteration_title, ->(iteration_title) { joins(:iteration).where(sprints: { title: iteration_title }) }
+      scope :without_iteration_title, ->(iteration_title) { left_outer_joins(:iteration).where('sprints.title != ? OR sprints.id IS NULL', iteration_title) }
       scope :on_status_page, -> do
         joins(project: :status_page_setting)
         .where(status_page_settings: { enabled: true })

ee/app/views/shared/issuable/_filter_iteration.html.haml

+- type = local_assigns.fetch(:type)
+- return unless type == :issues || type == :boards || type == :boards_modal
+
+#js-dropdown-iteration.filtered-search-input-dropdown-menu.dropdown-menu
+  %ul{ 'data-dropdown' => true }
+    %li.filter-dropdown-item{ 'data-value' => 'None' }
+      %button.btn.btn-link
+        = _('None')
+    %li.filter-dropdown-item{ 'data-value' => 'Any' }
+      %button.btn.btn-link
+        = _('Any')
+    %li.divider.droplab-item-ignore
+  %ul.filter-dropdown{ data: { dropdown: true, dynamic: true } }
+    %li.filter-dropdown-item
+      %button.btn.btn-link{ type: 'button' }
+        -# haml-lint:disable NoPlainNodes
+        %span.dropdown-light-content
+          {{title}}

ee/changelogs/unreleased/118742-iterations-in-filter-bar.yml

+---
+title: Allow filtering by iterations in issue API
+merge_request: 44690
+author:
+type: added

ee/config/feature_flags/development/filter_bar_iterations.yml

+---
+name: filter_bar_iterations
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/44690
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/118742
+milestone: '13.6'
+type: development
+group: group::project management
+default_enabled: false

ee/lib/ee/api/helpers/issues_helpers.rb

@@ -14,6 +14,14 @@ module EE
             mutually_exclusive :epic_id, :epic_iid
           end
 
+          params :negatable_issue_filter_params_ee do
+            optional :iteration_id, types: [Integer, String], integer_none_any: true,
+                     desc: 'Return issues which are assigned to the iteration with the given ID'
+            optional :iteration_title, type: String,
+                     desc: 'Return issues which are assigned to the iteration with the given title'
+            mutually_exclusive :iteration_id, :iteration_title
+          end
+
           params :optional_issues_params_ee do
             optional :weight, types: [Integer, String], integer_none_any: true, desc: 'The weight of the issue'
             optional :epic_id, types: [Integer, String], integer_none_any: true, desc: 'The ID of an epic associated with the issues'

ee/spec/features/issues/filtered_search/filter_issues_by_iteration_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Filter issues by iteration', :js do
+  include FilteredSearchHelpers
+
+  let_it_be(:group) { create(:group, :public) }
+  let_it_be(:project) { create(:project, :public, group: group) }
+
+  let_it_be(:iteration_1) { create(:iteration, group: group) }
+  let_it_be(:iteration_2) { create(:iteration, group: group) }
+
+  let_it_be(:iteration_1_issue) { create(:issue, project: project, iteration: iteration_1) }
+  let_it_be(:iteration_2_issue) { create(:issue, project: project, iteration: iteration_2) }
+  let_it_be(:no_iteration_issue) { create(:issue, project: project) }
+
+  shared_examples 'filters by iteration' do
+    context 'when iterations are not available' do
+      before do
+        stub_licensed_features(iterations: false)
+
+        visit page_path
+      end
+
+      it 'does not show the iteration filter option' do
+        find('.filtered-search').set('iter')
+
+        expect(find('#js-dropdown-hint')).not_to have_selector('.filter-dropdown .filter-dropdown-item', text: 'Iteration')
+      end
+    end
+
+    context 'when iterations are available' do
+      before do
+        stub_licensed_features(iterations: true)
+
+        visit page_path
+      end
+
+      it 'filters by iteration' do
+        input_filtered_search("iteration:=\"#{iteration_1.title}\"")
+
+        aggregate_failures do
+          expect(page).to have_content(iteration_1_issue.title)
+          expect(page).not_to have_content(iteration_2_issue.title)
+          expect(page).not_to have_content(no_iteration_issue.title)
+        end
+      end
+
+      it 'filters by negated iteration' do
+        page.within('.filtered-search-wrapper') do
+          find('.filtered-search').set('iter')
+          click_button('Iteration')
+
+          find('.btn-helptext', text: 'is not').click
+          click_button(iteration_1.title)
+
+          find('.filtered-search').send_keys(:enter)
+        end
+
+        aggregate_failures do
+          expect(page).not_to have_content(iteration_1_issue.title)
+          expect(page).to have_content(iteration_2_issue.title)
+          expect(page).to have_content(no_iteration_issue.title)
+        end
+      end
+    end
+  end
+
+  context 'project issues list' do
+    let(:page_path) { project_issues_path(project) }
+    let(:issue_title_selector) { '.issue .title' }
+
+    it_behaves_like 'filters by iteration'
+
+    context 'when vue_issuables_list is disabled' do
+      before do
+        stub_feature_flags(vue_issuables_list: false)
+      end
+
+      it_behaves_like 'filters by iteration'
+    end
+  end
+
+  context 'group issues list' do
+    let(:page_path) { issues_group_path(group) }
+    let(:issue_title_selector) { '.issue .title' }
+
+    it_behaves_like 'filters by iteration'
+
+    context 'when vue_issuables_list is disabled' do
+      before do
+        stub_feature_flags(vue_issuables_list: false)
+      end
+
+      it_behaves_like 'filters by iteration'
+    end
+  end
+
+  context 'project board' do
+    let_it_be(:board) { create(:board, project: project) }
+
+    let(:page_path) { project_board_path(project, board) }
+    let(:issue_title_selector) { '.board-card .board-card-title' }
+
+    it_behaves_like 'filters by iteration'
+  end
+
+  context 'group board' do
+    let_it_be(:board) { create(:board, group: group) }
+
+    let(:page_path) { group_board_path(group, board) }
+    let(:issue_title_selector) { '.board-card .board-card-title' }
+
+    before do
+      stub_feature_flags(graphql_board_lists: false)
+    end
+
+    it_behaves_like 'filters by iteration'
+  end
+end

ee/spec/finders/issues_finder_spec.rb

@@ -170,6 +170,22 @@ RSpec.describe IssuesFinder do
           end
         end
 
+        context 'filter issue by iteration title' do
+          let(:params) { { iteration_title: iteration_1.title } }
+
+          it 'returns all issues with the iteration title' do
+            expect(issues).to contain_exactly(iteration_1_issue)
+          end
+        end
+
+        context 'filter issue by negated iteration title' do
+          let(:params) { { not: { iteration_title: iteration_1.title } } }
+
+          it 'returns all issues that do not match the iteration title' do
+            expect(issues).to contain_exactly(issue1, issue2, issue3, issue4, iteration_2_issue)
+          end
+        end
+
         context 'without iteration_id param' do
           let(:params) { { iteration_id: nil } }
 

ee/spec/helpers/search_helper_spec.rb

@@ -49,6 +49,67 @@ RSpec.describe SearchHelper do
         expect(options[:data][:'multiple-assignees']).to eq('true')
       end
     end
+
+    describe 'iterations-endpoint' do
+      let_it_be(:group, refind: true) { create(:group) }
+      let_it_be(:project_under_group, refind: true) { create(:project, group: group) }
+
+      context 'when iterations are available' do
+        before do
+          stub_licensed_features(iterations: true)
+        end
+
+        it 'includes iteration endpoint in project context' do
+          @project = project_under_group
+
+          expect(options[:data]['iterations-endpoint']).to eq(expose_path(api_v4_projects_iterations_path(id: @project.id)))
+        end
+
+        it 'includes iteration endpoint in group context' do
+          @group = group
+
+          expect(options[:data]['iterations-endpoint']).to eq(expose_path(api_v4_groups_iterations_path(id: @group.id)))
+        end
+
+        it 'does not include iterations endpoint for projects under a namespace' do
+          @project = create(:project, namespace: create(:namespace))
+
+          expect(options[:data]['iterations-endpoint']).to be(nil)
+        end
+
+        it 'does not include iterations endpoint in dashboard context' do
+          expect(options[:data]['iterations-endpoint']).to be(nil)
+        end
+
+        context 'when feature flag is disabled' do
+          before do
+            stub_feature_flags(filter_bar_iterations: false)
+          end
+
+          it 'does not include iterations endpoint' do
+            expect(options[:data]['iterations-endpoint']).to be(nil)
+          end
+        end
+      end
+
+      context 'when iterations are not available' do
+        before do
+          stub_licensed_features(iterations: false)
+        end
+
+        it 'does not include iterations endpoint in project context' do
+          @project = project_under_group
+
+          expect(options[:data]['iterations-endpoint']).to be(nil)
+        end
+
+        it 'does not include iterations endpoint in group context' do
+          @group = group
+
+          expect(options[:data]['iterations-endpoint']).to be(nil)
+        end
+      end
+    end
   end
 
   describe 'search_autocomplete_opts' do

ee/spec/models/issue_spec.rb

@@ -209,6 +209,18 @@ RSpec.describe Issue do
           expect(described_class.in_iterations([iteration1])).to eq [iteration1_issue]
         end
       end
+
+      describe '.with_iteration_title' do
+        it 'returns only issues with iterations that match the title' do
+          expect(described_class.with_iteration_title(iteration1.title)).to eq [iteration1_issue]
+        end
+      end
+
+      describe '.without_iteration_title' do
+        it 'returns only issues without iterations or have iterations that do not match the title' do
+          expect(described_class.without_iteration_title(iteration1.title)).to contain_exactly(issue_no_iteration, iteration2_issue)
+        end
+      end
     end
 
     context 'status page published' do

ee/spec/requests/api/issues_spec.rb

@@ -179,6 +179,38 @@ RSpec.describe API::Issues, :mailer do
       it_behaves_like 'filtering by epic_id' do
         let(:endpoint) { '/issues' }
       end
+
+      context 'filtering by iteration' do
+        let_it_be(:iteration_1) { create(:iteration, group: group) }
+        let_it_be(:iteration_2) { create(:iteration, group: group) }
+        let_it_be(:iteration_1_issue) { create(:issue, project: group_project, iteration: iteration_1) }
+        let_it_be(:iteration_2_issue) { create(:issue, project: group_project, iteration: iteration_2) }
+        let_it_be(:no_iteration_issue) { create(:issue, project: group_project) }
+
+        it 'returns issues with specific iteration' do
+          get api('/issues', user), params: { iteration_id: iteration_1.id }
+
+          expect_response_contain_exactly(iteration_1_issue.id)
+        end
+
+        it 'returns issues with no iteration' do
+          get api('/issues', user), params: { iteration_id: 'None' }
+
+          expect_response_contain_exactly(no_iteration_issue.id)
+        end
+
+        it 'returns issues with any iteration' do
+          get api('/issues', user), params: { iteration_id: 'Any' }
+
+          expect_response_contain_exactly(iteration_1_issue.id, iteration_2_issue.id)
+        end
+
+        it 'returns issues with a specific iteration title' do
+          get api('/issues', user), params: { iteration_title: iteration_1.title }
+
+          expect_response_contain_exactly(iteration_1_issue.id)
+        end
+      end
     end
   end
 

lib/api/helpers/issues_helpers.rb

@@ -5,6 +5,9 @@ module API
     module IssuesHelpers
       extend Grape::API::Helpers
 
+      params :negatable_issue_filter_params_ee do
+      end
+
       params :optional_issue_params_ee do
       end
 

lib/api/issues.rb

@@ -28,6 +28,8 @@ module API
                  coerce_with: Validations::Validators::CheckAssigneesCount.coerce,
                  desc: 'Return issues which are assigned to the user with the given username'
         mutually_exclusive :assignee_id, :assignee_username
+
+        use :negatable_issue_filter_params_ee
       end
 
       params :issues_stats_params do