Expose queries over a users merge requests

We expose the graph:

  User -[authored]-----> MergeRequest
       -[assigned to] -> MergeRequest

Via two new edges on `User`: `authoredMergeRequests` and
`assignedMergeRequests`.

As an incidental improvement, `User.state` is made into an `enum` - this
change is backwards compatible since the output is the same: a string.

app/graphql/types/query_type.rb

@@ -56,6 +56,10 @@ module Types
           description: 'Text to echo back',
           resolver: Resolvers::EchoResolver
 
+    field :user, Types::UserType, null: true,
+          description: 'Find a user on this instance',
+          resolver: Resolvers::UserResolver
+
     def design_management
       DesignManagementObject.new(nil)
     end

app/graphql/types/user_state_enum.rb

+# frozen_string_literal: true
+
+module Types
+  class UserStateEnum < BaseEnum
+    graphql_name 'UserState'
+    description 'Possible states of a user'
+
+    value 'active', 'The user is active and is able to use the system', value: 'active'
+    value 'blocked', 'The user has been blocked and is prevented from using the system', value: 'blocked'
+    value 'deactivated', 'The user is no longer active and is unable to use the system', value: 'deactivated'
+  end
+end

app/graphql/types/user_type.rb

@@ -12,12 +12,12 @@ module Types
 
     field :id, GraphQL::ID_TYPE, null: false,
           description: 'ID of the user'
-    field :name, GraphQL::STRING_TYPE, null: false,
-          description: 'Human-readable name of the user'
-    field :state, GraphQL::STRING_TYPE, null: false,
-          description: 'State of the issue'
     field :username, GraphQL::STRING_TYPE, null: false,
           description: 'Username of the user. Unique within this instance of GitLab'
+    field :name, GraphQL::STRING_TYPE, null: false,
+          description: 'Human-readable name of the user'
+    field :state, Types::UserStateEnum, null: false,
+          description: 'State of the user'
     field :avatar_url, GraphQL::STRING_TYPE, null: true,
           description: "URL of the user's avatar"
     field :web_url, GraphQL::STRING_TYPE, null: false,
@@ -26,6 +26,14 @@ module Types
           resolver: Resolvers::TodoResolver,
           description: 'Todos of the user'
 
+    # Merge request field: MRs can be either authored or assigned:
+    field :authored_merge_requests, Types::MergeRequestType.connection_type, null: true,
+          resolver: Resolvers::AuthoredMergeRequestsResolver,
+          description: 'Merge Requests authored by the user'
+    field :assigned_merge_requests, Types::MergeRequestType.connection_type, null: true,
+          resolver: Resolvers::AssignedMergeRequestsResolver,
+          description: 'Merge Requests assigned to the user'
+
     field :snippets,
           Types::SnippetType.connection_type,
           null: true,

changelogs/unreleased/ajk-GQL-user-mrs.yml

+---
+title: Add GraphQL support for authored and assigned Merge Requests
+merge_request: 31227
+author:
+type: added

doc/api/graphql/reference/gitlab_schema.graphql

@@ -9348,7 +9348,7 @@ type Query {
   ): SnippetConnection
 
   """
-  Find a user
+  Find a user on this instance
   """
   user(
     """
@@ -12053,6 +12053,126 @@ type UpdateSnippetPayload {
 scalar Upload
 
 type User {
+  """
+  Merge Requests assigned to the user
+  """
+  assignedMergeRequests(
+    """
+    Returns the elements in the list that come after the specified cursor.
+    """
+    after: String
+
+    """
+    Returns the elements in the list that come before the specified cursor.
+    """
+    before: String
+
+    """
+    Returns the first _n_ elements from the list.
+    """
+    first: Int
+
+    """
+    Array of IIDs of merge requests, for example `[1, 2]`
+    """
+    iids: [String!]
+
+    """
+    Array of label names. All resolved merge requests will have all of these labels.
+    """
+    labels: [String!]
+
+    """
+    Returns the last _n_ elements from the list.
+    """
+    last: Int
+
+    """
+    The global ID of the project the authored merge requests should be in. Incompatible with projectPath.
+    """
+    projectId: ID
+
+    """
+    The full-path of the project the authored merge requests should be in. Incompatible with projectId.
+    """
+    projectPath: String
+
+    """
+    Array of source branch names. All resolved merge requests will have one of these branches as their source.
+    """
+    sourceBranches: [String!]
+
+    """
+    A merge request state. If provided, all resolved merge requests will have this state.
+    """
+    state: MergeRequestState
+
+    """
+    Array of target branch names. All resolved merge requests will have one of these branches as their target.
+    """
+    targetBranches: [String!]
+  ): MergeRequestConnection
+
+  """
+  Merge Requests authored by the user
+  """
+  authoredMergeRequests(
+    """
+    Returns the elements in the list that come after the specified cursor.
+    """
+    after: String
+
+    """
+    Returns the elements in the list that come before the specified cursor.
+    """
+    before: String
+
+    """
+    Returns the first _n_ elements from the list.
+    """
+    first: Int
+
+    """
+    Array of IIDs of merge requests, for example `[1, 2]`
+    """
+    iids: [String!]
+
+    """
+    Array of label names. All resolved merge requests will have all of these labels.
+    """
+    labels: [String!]
+
+    """
+    Returns the last _n_ elements from the list.
+    """
+    last: Int
+
+    """
+    The global ID of the project the authored merge requests should be in. Incompatible with projectPath.
+    """
+    projectId: ID
+
+    """
+    The full-path of the project the authored merge requests should be in. Incompatible with projectId.
+    """
+    projectPath: String
+
+    """
+    Array of source branch names. All resolved merge requests will have one of these branches as their source.
+    """
+    sourceBranches: [String!]
+
+    """
+    A merge request state. If provided, all resolved merge requests will have this state.
+    """
+    state: MergeRequestState
+
+    """
+    Array of target branch names. All resolved merge requests will have one of these branches as their target.
+    """
+    targetBranches: [String!]
+  ): MergeRequestConnection
+
   """
   URL of the user's avatar
   """
@@ -12109,9 +12229,9 @@ type User {
   ): SnippetConnection
 
   """
-  State of the issue
+  State of the user
   """
-  state: String!
+  state: UserState!
 
   """
   Todos of the user
@@ -12226,6 +12346,26 @@ type UserPermissions {
   createSnippet: Boolean!
 }
 
+"""
+Possible states of a user
+"""
+enum UserState {
+  """
+  The user is active and is able to use the system
+  """
+  active
+
+  """
+  The user has been blocked and is prevented from using the system
+  """
+  blocked
+
+  """
+  The user is no longer active and is unable to use the system
+  """
+  deactivated
+}
+
 enum VisibilityLevelsEnum {
   internal
   private

doc/api/graphql/reference/index.md

@@ -1819,7 +1819,7 @@ Autogenerated return type of UpdateSnippet
 | `avatarUrl` | String | URL of the user's avatar |
 | `id` | ID! | ID of the user |
 | `name` | String! | Human-readable name of the user |
-| `state` | String! | State of the issue |
+| `state` | UserState! | State of the user |
 | `userPermissions` | UserPermissions! | Permissions for the current user on the resource |
 | `username` | String! | Username of the user. Unique within this instance of GitLab |
 | `webUrl` | String! | Web URL of the user |

spec/graphql/resolvers/user_resolver_spec.rb

@@ -40,6 +40,6 @@ describe Resolvers::UserResolver do
   private
 
   def resolve_user(args = {})
-    resolve(described_class, args: args)
+    sync(resolve(described_class, args: args))
   end
 end

spec/graphql/types/user_type_spec.rb

@@ -10,6 +10,7 @@ describe GitlabSchema.types['User'] do
   it 'has the expected fields' do
     expected_fields = %w[
       id user_permissions snippets name username avatarUrl webUrl todos state
+      authoredMergeRequests assignedMergeRequests
     ]
 
     expect(described_class).to have_graphql_fields(*expected_fields)

spec/requests/api/graphql/user_query_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'getting user information' do
+  include GraphqlHelpers
+
+  let(:query) do
+    graphql_query_for(:user, user_params, user_fields)
+  end
+
+  let(:user_fields) { all_graphql_fields_for('User', max_depth: 2) }
+
+  context 'no parameters are provided' do
+    let(:user_params) { nil }
+
+    it 'mentions the missing required parameters' do
+      post_graphql(query)
+
+      expect_graphql_errors_to_include(/username/)
+    end
+  end
+
+  context 'looking up a user by username' do
+    let_it_be(:project_a) { create(:project, :repository) }
+    let_it_be(:project_b) { create(:project, :repository) }
+    let_it_be(:user, reload: true) { create(:user, developer_projects: [project_a, project_b]) }
+    let_it_be(:authorised_user) { create(:user, developer_projects: [project_a, project_b]) }
+    let_it_be(:unauthorized_user) { create(:user) }
+
+    let_it_be(:assigned_mr) do
+      create(:merge_request, :unique_branches,
+             source_project: project_a, assignees: [user])
+    end
+    let_it_be(:assigned_mr_b) do
+      create(:merge_request, :unique_branches,
+             source_project: project_b, assignees: [user])
+    end
+    let_it_be(:assigned_mr_c) do
+      create(:merge_request, :unique_branches,
+             source_project: project_b, assignees: [user])
+    end
+    let_it_be(:authored_mr) do
+      create(:merge_request, :unique_branches,
+             source_project: project_a, author: user)
+    end
+    let_it_be(:authored_mr_b) do
+      create(:merge_request, :unique_branches,
+             source_project: project_b, author: user)
+    end
+    let_it_be(:authored_mr_c) do
+      create(:merge_request, :unique_branches,
+             source_project: project_b, author: user)
+    end
+
+    let(:current_user) { authorised_user }
+    let(:authored_mrs) { graphql_data_at(:user, :authored_merge_requests, :nodes) }
+    let(:assigned_mrs) { graphql_data_at(:user, :assigned_merge_requests, :nodes) }
+    let(:user_params) { { username: user.username } }
+
+    before do
+      post_graphql(query, current_user: current_user)
+    end
+
+    context 'the user is an active user' do
+      it_behaves_like 'a working graphql query'
+
+      it 'can access user profile fields' do
+        presenter = UserPresenter.new(user)
+
+        expect(graphql_data['user']).to match(
+          a_hash_including(
+            'id' => global_id_of(user),
+            'state' => presenter.state,
+            'name' => presenter.name,
+            'username' => presenter.username,
+            'webUrl' => presenter.web_url,
+            'avatarUrl' => presenter.avatar_url
+          ))
+      end
+
+      describe 'assignedMergeRequests' do
+        let(:user_fields) do
+          query_graphql_field(:assigned_merge_requests, mr_args, 'nodes { id }')
+        end
+        let(:mr_args) { nil }
+
+        it_behaves_like 'a working graphql query'
+
+        it 'can be found' do
+          expect(assigned_mrs).to contain_exactly(
+            a_hash_including('id' => global_id_of(assigned_mr)),
+            a_hash_including('id' => global_id_of(assigned_mr_b)),
+            a_hash_including('id' => global_id_of(assigned_mr_c))
+          )
+        end
+
+        context 'applying filters' do
+          context 'filtering by IID without specifying a project' do
+            let(:mr_args) do
+              { iids: [assigned_mr_b.iid.to_s] }
+            end
+
+            it 'return an argument error that mentions the missing fields' do
+              expect_graphql_errors_to_include(/projectPath/)
+            end
+          end
+
+          context 'filtering by project path and IID' do
+            let(:mr_args) do
+              { project_path: project_b.full_path, iids: [assigned_mr_b.iid.to_s] }
+            end
+
+            it 'selects the correct MRs' do
+              expect(assigned_mrs).to contain_exactly(
+                a_hash_including('id' => global_id_of(assigned_mr_b))
+              )
+            end
+          end
+
+          context 'filtering by project path' do
+            let(:mr_args) do
+              { project_path: project_b.full_path }
+            end
+
+            it 'selects the correct MRs' do
+              expect(assigned_mrs).to contain_exactly(
+                a_hash_including('id' => global_id_of(assigned_mr_b)),
+                a_hash_including('id' => global_id_of(assigned_mr_c))
+              )
+            end
+          end
+        end
+
+        context 'the current user does not have access' do
+          let(:current_user) { unauthorized_user }
+
+          it 'cannot be found' do
+            expect(assigned_mrs).to be_empty
+          end
+        end
+      end
+
+      describe 'authoredMergeRequests' do
+        let(:user_fields) do
+          query_graphql_field(:authored_merge_requests, mr_args, 'nodes { id }')
+        end
+        let(:mr_args) { nil }
+
+        it_behaves_like 'a working graphql query'
+
+        it 'can be found' do
+          expect(authored_mrs).to contain_exactly(
+            a_hash_including('id' => global_id_of(authored_mr)),
+            a_hash_including('id' => global_id_of(authored_mr_b)),
+            a_hash_including('id' => global_id_of(authored_mr_c))
+          )
+        end
+
+        context 'applying filters' do
+          context 'filtering by IID without specifying a project' do
+            let(:mr_args) do
+              { iids: [authored_mr_b.iid.to_s] }
+            end
+
+            it 'return an argument error that mentions the missing fields' do
+              expect_graphql_errors_to_include(/projectPath/)
+            end
+          end
+
+          context 'filtering by project path and IID' do
+            let(:mr_args) do
+              { project_path: project_b.full_path, iids: [authored_mr_b.iid.to_s] }
+            end
+
+            it 'selects the correct MRs' do
+              expect(authored_mrs).to contain_exactly(
+                a_hash_including('id' => global_id_of(authored_mr_b))
+              )
+            end
+          end
+
+          context 'filtering by project path' do
+            let(:mr_args) do
+              { project_path: project_b.full_path }
+            end
+
+            it 'selects the correct MRs' do
+              expect(authored_mrs).to contain_exactly(
+                a_hash_including('id' => global_id_of(authored_mr_b)),
+                a_hash_including('id' => global_id_of(authored_mr_c))
+              )
+            end
+          end
+        end
+
+        context 'the current user does not have access' do
+          let(:current_user) { unauthorized_user }
+
+          it 'cannot be found' do
+            expect(authored_mrs).to be_empty
+          end
+        end
+      end
+    end
+
+    context 'the user is private' do
+      before do
+        user.update(private_profile: true)
+        post_graphql(query, current_user: current_user)
+      end
+
+      context 'we only request basic fields' do
+        let(:user_fields) { %i[id name username state web_url avatar_url] }
+
+        it_behaves_like 'a working graphql query'
+      end
+
+      context 'we request the authoredMergeRequests' do
+        let(:user_fields) { 'authoredMergeRequests { nodes { id } }' }
+
+        it_behaves_like 'a working graphql query'
+
+        it 'cannot be found' do
+          expect(authored_mrs).to be_empty
+        end
+
+        context 'the current user is the user' do
+          let(:current_user) { user }
+
+          it 'can be found' do
+            expect(authored_mrs).to include(
+              a_hash_including('id' => global_id_of(authored_mr))
+            )
+          end
+        end
+      end
+
+      context 'we request the assignedMergeRequests' do
+        let(:user_fields) { 'assignedMergeRequests { nodes { id } }' }
+
+        it_behaves_like 'a working graphql query'
+
+        it 'cannot be found' do
+          expect(assigned_mrs).to be_empty
+        end
+
+        context 'the current user is the user' do
+          let(:current_user) { user }
+
+          it 'can be found' do
+            expect(assigned_mrs).to include(
+              a_hash_including('id' => global_id_of(assigned_mr))
+            )
+          end
+        end
+      end
+    end
+  end
+end

spec/support/helpers/graphql_helpers.rb

@@ -153,7 +153,15 @@ module GraphqlHelpers
   end
 
   def wrap_fields(fields)
-    fields = Array.wrap(fields).join("\n")
+    fields = Array.wrap(fields).map do |field|
+      case field
+      when Symbol
+        GraphqlHelpers.fieldnamerize(field)
+      else
+        field
+      end
+    end.join("\n")
+
     return unless fields.present?
 
     <<~FIELDS