Add REST API for listing iterations

This will be used for the filter bar autocomplete. We do not have
project iterations right now but I created the project iterations
endpoiont for retrieving ancestor iterations just like we do with the
GraphQL API.

doc/api/api_resources.md

@@ -38,6 +38,7 @@ The following API resources are available in the project context:
 | [Issues Statistics](issues_statistics.md)                           | `/projects/:id/issues_statistics` (also available for groups and standalone)                                                                                                                          |
 | [Issue boards](boards.md)                                           | `/projects/:id/boards`                                                                                                                                                                                |
 | [Issue links](issue_links.md) **(STARTER)**                         | `/projects/:id/issues/.../links`                                                                                                                                                                      |
+| [Iterations](iterations.md) **(STARTER)**                           | `/projects/:id/iterations` (also available for groups)                                                                                                                                                                     |
 | [Jobs](jobs.md)                                                     | `/projects/:id/jobs`, `/projects/:id/pipelines/.../jobs`                                                                                                                                              |
 | [Labels](labels.md)                                                 | `/projects/:id/labels`                                                                                                                                                                                |
 | [Managed licenses](managed_licenses.md) **(ULTIMATE)**              | `/projects/:id/managed_licenses`                                                                                                                                                                      |
@@ -97,6 +98,7 @@ The following API resources are available in the group context:
 | [Groups](groups.md)                                              | `/groups`, `/groups/.../subgroups`                                               |
 | [Group badges](group_badges.md)                                  | `/groups/:id/badges`                                                             |
 | [Group issue boards](group_boards.md)                            | `/groups/:id/boards`                                                             |
+| [Group iterations](group_iterations.md) **(STARTER)**            | `/groups/:id/iterations` (also available for projects)                           |
 | [Group labels](group_labels.md)                                  | `/groups/:id/labels`                                                             |
 | [Group-level variables](group_level_variables.md)                | `/groups/:id/variables`                                                          |
 | [Group milestones](group_milestones.md)                          | `/groups/:id/milestones`                                                         |

doc/api/group_iterations.md

+---
+stage: Plan
+group: Project Management
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
+# Group iterations API **(STARTER)**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/118742) in [GitLab Starter](https://about.gitlab.com/pricing/) 13.5.
+
+This page describes the group iterations API.
+There's a separate [project iterations API](./iterations.md) page.
+
+## List group iterations
+
+Returns a list of group iterations.
+
+```plaintext
+GET /groups/:id/iterations
+GET /groups/:id/iterations?state=opened
+GET /groups/:id/iterations?state=closed
+GET /groups/:id/iterations?title=1.0
+GET /groups/:id/iterations?search=version
+```
+
+| Attribute           | Type    | Required | Description |
+| ------------------- | ------- | -------- | ----------- |
+| `state`             | string  | no       | Return only `opened`, `upcoming`, `started`, `closed`, or `all` iterations. Defaults to `all`. |
+| `search`            | string  | no       | Return only iterations with a title matching the provided string.                              |
+| `include_ancestors` | boolean | no       | Include iterations from parent group and its ancestors. Defaults to `true`.                    |
+
+Example request:
+
+```shell
+curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/groups/5/iterations"
+```
+
+Example response:
+
+```json
+[
+  {
+    "id": 53,
+    "iid": 13,
+    "group_id": 5,
+    "title": "Iteration II",
+    "description": "Ipsum Lorem ipsum",
+    "state": 2,
+    "created_at": "2020-01-27T05:07:12.573Z",
+    "updated_at": "2020-01-27T05:07:12.573Z",
+    "due_date": "2020-02-01",
+    "start_date": "2020-02-14"
+  }
+]
+```

doc/api/group_milestones.md

@@ -9,7 +9,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/12819) in GitLab 9.5.
 
 This page describes the group milestones API.
-There's a separate [project milestones API](./group_milestones.md) page.
+There's a separate [project milestones API](./milestones.md) page.
 
 ## List group milestones
 

doc/api/iterations.md

+---
+stage: Plan
+group: Project Management
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
+# Project iterations API **(STARTER)**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/118742) in [GitLab Starter](https://about.gitlab.com/pricing/) 13.5.
+
+This page describes the project iterations API.
+There's a separate [group iterations API](./group_iterations.md) page.
+
+As of GitLab 13.5, we don't have project-level iterations, but you can use this endpoint to fetch the iterations of the project's ancestor groups.
+
+## List project iterations
+
+Returns a list of project iterations.
+
+```plaintext
+GET /projects/:id/iterations
+GET /projects/:id/iterations?state=opened
+GET /projects/:id/iterations?state=closed
+GET /projects/:id/iterations?title=1.0
+GET /projects/:id/iterations?search=version
+```
+
+| Attribute           | Type    | Required | Description |
+| ------------------- | ------- | -------- | ----------- |
+| `state`             | string  | no       | Return only `opened`, `upcoming`, `started`, `closed`, or `all` iterations. Defaults to `all`. |
+| `search`            | string  | no       | Return only iterations with a title matching the provided string.                              |
+| `include_ancestors` | boolean | no       | Include iterations from parent group and its ancestors. Defaults to `true`.                    |
+
+Example request:
+
+```shell
+curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/projects/5/iterations"
+```
+
+Example response:
+
+```json
+[
+  {
+    "id": 53,
+    "iid": 13,
+    "group_id": 5,
+    "title": "Iteration II",
+    "description": "Ipsum Lorem ipsum",
+    "state": 2,
+    "created_at": "2020-01-27T05:07:12.573Z",
+    "updated_at": "2020-01-27T05:07:12.573Z",
+    "due_date": "2020-02-01",
+    "start_date": "2020-02-14"
+  }
+]
+```

ee/app/finders/iterations_finder.rb

@@ -15,6 +15,27 @@ class IterationsFinder
 
   attr_reader :params, :current_user
 
+  class << self
+    def params_for_parent(parent, include_ancestors: false)
+      case parent
+      when Group
+        if include_ancestors
+          { group_ids: parent.self_and_ancestors.select(:id) }
+        else
+          { group_ids: parent.id }
+        end
+      when Project
+        if include_ancestors && parent.parent_id.present?
+          { group_ids: parent.parent.self_and_ancestors.select(:id), project_ids: parent.id }
+        else
+          { project_ids: parent.id }
+        end
+      else
+        raise ArgumentError, 'Invalid parent class. Only Project and Group are supported.'
+      end
+    end
+  end
+
   def initialize(current_user, params = {})
     @params = params
     @current_user = current_user

ee/app/graphql/resolvers/iterations_resolver.rb

@@ -41,36 +41,20 @@ module Resolvers
     private
 
     def iterations_finder_params(args)
-      {
+      IterationsFinder.params_for_parent(parent, include_ancestors: args[:include_ancestors]).merge!(
         id: args[:id],
         iid: args[:iid],
         state: args[:state] || 'all',
         start_date: args[:start_date],
         end_date: args[:end_date],
         search_title: args[:title]
-      }.merge(parent_id_parameter(args[:include_ancestors]))
+      )
     end
 
     def parent
       @parent ||= object.respond_to?(:sync) ? object.sync : object
     end
 
-    def parent_id_parameter(include_ancestors)
-      if parent.is_a?(Group)
-        if include_ancestors
-          { group_ids: parent.self_and_ancestors.select(:id) }
-        else
-          { group_ids: parent.id }
-        end
-      elsif parent.is_a?(Project)
-        if include_ancestors && parent.parent_id.present?
-          { group_ids: parent.parent.self_and_ancestors.select(:id), project_ids: parent.id }
-        else
-          { project_ids: parent.id }
-        end
-      end
-    end
-
     def authorize!
       Ability.allowed?(context[:current_user], :read_iteration, parent) || raise_resource_not_available_error!
     end

ee/changelogs/unreleased/add-iterations-rest-api.yml

+---
+title: Add REST API for listing iterations
+merge_request: 44685
+author:
+type: added

ee/lib/api/iterations.rb

+# frozen_string_literal: true
+
+module API
+  class Iterations < ::API::Base
+    include PaginationParams
+
+    helpers do
+      params :list_params do
+        optional :state, type: String, values: %w[opened upcoming started closed all], default: 'all',
+                 desc: 'Return "opened", "upcoming", "started", "closed", or "all" milestones'
+        optional :search, type: String, desc: 'The search criteria for the title of the iteration'
+        optional :include_ancestors, type: Grape::API::Boolean, default: true,
+                 desc: 'Include iterations from parent and its ancestors'
+        use :pagination
+      end
+
+      def list_iterations_for(parent)
+        iterations = IterationsFinder.new(current_user, iterations_finder_params(parent)).execute
+
+        present paginate(iterations), with: EE::API::Entities::Iteration
+      end
+
+      def iterations_finder_params(parent)
+        IterationsFinder.params_for_parent(parent, include_ancestors: params[:include_ancestors]).merge!(
+          state: params[:state],
+          search_title: params[:search]
+        )
+      end
+    end
+
+    params do
+      requires :id, type: String, desc: 'The ID of a project'
+    end
+    resource :projects, requirements: API::NAMESPACE_OR_PROJECT_REQUIREMENTS do
+      desc 'Get a list of project iterations' do
+        detail 'This feature was introduced in GitLab 13.5'
+        success EE::API::Entities::Iteration
+      end
+      params do
+        use :list_params
+      end
+      get ":id/iterations" do
+        authorize! :read_iteration, user_project
+
+        list_iterations_for(user_project)
+      end
+    end
+
+    params do
+      requires :id, type: String, desc: 'The ID of a group'
+    end
+    resource :groups, requirements: API::NAMESPACE_OR_PROJECT_REQUIREMENTS do
+      desc 'Get a list of group iterations' do
+        detail 'This feature was introduced in GitLab 13.5'
+        success EE::API::Entities::Iteration
+      end
+      params do
+        use :list_params
+      end
+      get ":id/iterations" do
+        authorize! :read_iteration, user_group
+
+        list_iterations_for(user_group)
+      end
+    end
+  end
+end

ee/lib/ee/api/api.rb

@@ -47,6 +47,7 @@ module EE
         mount ::API::ProtectedEnvironments
         mount ::API::ResourceWeightEvents
         mount ::API::ResourceIterationEvents
+        mount ::API::Iterations
       end
     end
   end

ee/lib/ee/gitlab/quick_actions/issue_actions.rb

@@ -135,9 +135,9 @@ module EE
           end
 
           def find_iterations(project, params = {})
-            group_ids = project.group.self_and_ancestors.map(&:id) if project.group
+            parent_params = ::IterationsFinder.params_for_parent(project, include_ancestors: true)
 
-            ::IterationsFinder.new(current_user, params.merge(project_ids: [project.id], group_ids: group_ids)).execute
+            ::IterationsFinder.new(current_user, params.merge(parent_params)).execute
           end
 
           desc _('Publish to status page')

ee/spec/finders/iterations_finder_spec.rb

@@ -159,5 +159,59 @@ RSpec.describe IterationsFinder do
         expect(finder.find_by(iid: iteration_from_project_1.iid)).to eq(iteration_from_project_1)
       end
     end
+
+    describe '.params_for_parent' do
+      let_it_be(:parent_group) { create(:group) }
+      let_it_be(:group) { create(:group, parent: parent_group) }
+      let_it_be(:project) { create(:project, group: group) }
+
+      context 'when parent is a project' do
+        subject { described_class.params_for_parent(project, include_ancestors: include_ancestors) }
+
+        context 'when include_ancestors is true' do
+          let(:include_ancestors) { true }
+
+          it 'returns project and ancestor group ids' do
+            expect(subject).to match(group_ids: contain_exactly(group, parent_group), project_ids: project.id)
+          end
+        end
+
+        context 'when include_ancestors is false' do
+          let(:include_ancestors) { false }
+
+          it 'returns project id' do
+            expect(subject).to eq(project_ids: project.id)
+          end
+        end
+      end
+
+      context 'when parent is a group' do
+        subject { described_class.params_for_parent(group, include_ancestors: include_ancestors) }
+
+        context 'when include_ancestors is true' do
+          let(:include_ancestors) { true }
+
+          it 'returns group and ancestor ids' do
+            expect(subject).to match(group_ids: contain_exactly(group, parent_group))
+          end
+        end
+
+        context 'when include_ancestors is false' do
+          let(:include_ancestors) { false }
+
+          it 'returns group id' do
+            expect(subject).to eq(group_ids: group.id)
+          end
+        end
+      end
+
+      context 'when parent is invalid' do
+        subject { described_class.params_for_parent(double(User)) }
+
+        it 'raises an ArgumentError' do
+          expect { subject }.to raise_error(ArgumentError, 'Invalid parent class. Only Project and Group are supported.')
+        end
+      end
+    end
   end
 end

ee/spec/requests/api/iterations_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe API::Iterations do
+  let_it_be(:user) { create(:user) }
+  let_it_be(:parent_group) { create(:group, :private) }
+  let_it_be(:group) { create(:group, :private, parent: parent_group) }
+
+  let_it_be(:iteration) { create(:iteration, group: group, title: 'search_title') }
+  let_it_be(:closed_iteration) { create(:iteration, :closed, group: group) }
+  let_it_be(:ancestor_iteration) { create(:iteration, group: parent_group) }
+
+  before_all do
+    parent_group.add_guest(user)
+  end
+
+  shared_examples 'iterations list' do
+    context 'when user does not have access' do
+      it 'returns 404' do
+        get api(api_path, nil)
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+
+    context 'when user has access' do
+      it 'returns a list of iterations' do
+        get api(api_path, user)
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response.size).to eq(3)
+        expect(json_response.map { |i| i['id'] }).to contain_exactly(iteration.id, closed_iteration.id, ancestor_iteration.id)
+      end
+
+      it 'returns iterations filtered by state' do
+        get api(api_path, user), params: { state: 'closed' }
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response.size).to eq(1)
+        expect(json_response.first['id']).to eq(closed_iteration.id)
+      end
+
+      it 'returns iterations filtered by title' do
+        get api(api_path, user), params: { search: 'search_' }
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response.size).to eq(1)
+        expect(json_response.first['id']).to eq(iteration.id)
+      end
+
+      it 'returns 400 when param is invalid' do
+        get api(api_path, user), params: { state: 'non-existent-state' }
+
+        expect(response).to have_gitlab_http_status(:bad_request)
+      end
+    end
+  end
+
+  describe 'GET /groups/:id/iterations' do
+    let(:api_path) { "/groups/#{group.id}/iterations" }
+
+    it_behaves_like 'iterations list'
+
+    it 'excludes ancestor iterations when include_ancestors is set to false' do
+      get api(api_path, user), params: { include_ancestors: false }
+
+      expect(response).to have_gitlab_http_status(:ok)
+      expect(json_response.size).to eq(2)
+      expect(json_response.map { |i| i['id'] }).to contain_exactly(iteration.id, closed_iteration.id)
+    end
+  end
+
+  describe 'GET /projects/:id/iterations' do
+    let_it_be(:project) { create(:project, :private, group: group) }
+
+    let(:api_path) { "/projects/#{project.id}/iterations" }
+
+    it_behaves_like 'iterations list'
+
+    it 'excludes ancestor iterations when include_ancestors is set to false' do
+      get api(api_path, user), params: { include_ancestors: false }
+
+      expect(response).to have_gitlab_http_status(:ok)
+      expect(json_response.size).to eq(0)
+    end
+  end
+end