Add mutation for changing due date of an issue

Add mutation base for Issues
Update graphQL docs
Add specs for IssueSetDueDate mutation
Update GraphQL schema

app/graphql/mutations/issues/base.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Issues
+    class Base < BaseMutation
+      include Mutations::ResolvesProject
+
+      argument :project_path, GraphQL::ID_TYPE,
+               required: true,
+               description: "The project the issue to mutate is in"
+
+      argument :iid, GraphQL::STRING_TYPE,
+               required: true,
+               description: "The iid of the issue to mutate"
+
+      field :issue,
+            Types::IssueType,
+            null: true,
+            description: "The issue after mutation"
+
+      authorize :update_issue
+
+      private
+
+      def find_object(project_path:, iid:)
+        project = resolve_project(full_path: project_path)
+        resolver = Resolvers::IssuesResolver
+          .single.new(object: project, context: context)
+
+        resolver.resolve(iid: iid)
+      end
+    end
+  end
+end

app/graphql/mutations/issues/set_due_date.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Issues
+    class SetDueDate < Base
+      graphql_name 'IssueSetDueDate'
+
+      argument :due_date,
+               Types::TimeType,
+               required: true,
+               description: 'The desired due date for the issue'
+
+      def resolve(project_path:, iid:, due_date:)
+        issue = authorized_find!(project_path: project_path, iid: iid)
+        project = issue.project
+
+        ::Issues::UpdateService.new(project, current_user, due_date: due_date)
+          .execute(issue)
+
+        {
+          issue: issue,
+          errors: issue.errors.full_messages
+        }
+      end
+    end
+  end
+end

app/graphql/types/mutation_type.rb

@@ -9,6 +9,7 @@ module Types
     mount_mutation Mutations::AwardEmojis::Add
     mount_mutation Mutations::AwardEmojis::Remove
     mount_mutation Mutations::AwardEmojis::Toggle
+    mount_mutation Mutations::Issues::SetDueDate
     mount_mutation Mutations::MergeRequests::SetLabels
     mount_mutation Mutations::MergeRequests::SetLocked
     mount_mutation Mutations::MergeRequests::SetMilestone

changelogs/unreleased/36313-graphql-mutation-for-changing-due-date-of-an-issue.yml

+---
+title: Add GraphQL mutation for changing due date of an issue
+merge_request: 20577
+author:
+type: added

doc/api/graphql/reference/gitlab_schema.graphql

@@ -2518,6 +2518,51 @@ type IssuePermissions {
   updateIssue: Boolean!
 }
 
+"""
+Autogenerated input type of IssueSetDueDate
+"""
+input IssueSetDueDateInput {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  The desired due date for the issue
+  """
+  dueDate: Time!
+
+  """
+  The iid of the issue to mutate
+  """
+  iid: String!
+
+  """
+  The project the issue to mutate is in
+  """
+  projectPath: ID!
+}
+
+"""
+Autogenerated return type of IssueSetDueDate
+"""
+type IssueSetDueDatePayload {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Reasons why the mutation failed.
+  """
+  errors: [String!]!
+
+  """
+  The issue after mutation
+  """
+  issue: Issue
+}
+
 """
 Values for sorting issues
 """
@@ -3511,6 +3556,7 @@ type Mutation {
   destroyNote(input: DestroyNoteInput!): DestroyNotePayload
   epicSetSubscription(input: EpicSetSubscriptionInput!): EpicSetSubscriptionPayload
   epicTreeReorder(input: EpicTreeReorderInput!): EpicTreeReorderPayload
+  issueSetDueDate(input: IssueSetDueDateInput!): IssueSetDueDatePayload
   mergeRequestSetAssignees(input: MergeRequestSetAssigneesInput!): MergeRequestSetAssigneesPayload
   mergeRequestSetLabels(input: MergeRequestSetLabelsInput!): MergeRequestSetLabelsPayload
   mergeRequestSetLocked(input: MergeRequestSetLockedInput!): MergeRequestSetLockedPayload

doc/api/graphql/reference/gitlab_schema.json

@@ -14112,6 +14112,33 @@
               "isDeprecated": false,
               "deprecationReason": null
             },
+            {
+              "name": "issueSetDueDate",
+              "description": null,
+              "args": [
+                {
+                  "name": "input",
+                  "description": null,
+                  "type": {
+                    "kind": "NON_NULL",
+                    "name": null,
+                    "ofType": {
+                      "kind": "INPUT_OBJECT",
+                      "name": "IssueSetDueDateInput",
+                      "ofType": null
+                    }
+                  },
+                  "defaultValue": null
+                }
+              ],
+              "type": {
+                "kind": "OBJECT",
+                "name": "IssueSetDueDatePayload",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
             {
               "name": "mergeRequestSetAssignees",
               "description": null,
@@ -14958,6 +14985,136 @@
           "enumValues": null,
           "possibleTypes": null
         },
+        {
+          "kind": "OBJECT",
+          "name": "IssueSetDueDatePayload",
+          "description": "Autogenerated return type of IssueSetDueDate",
+          "fields": [
+            {
+              "name": "clientMutationId",
+              "description": "A unique identifier for the client performing the mutation.",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "SCALAR",
+                "name": "String",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "errors",
+              "description": "Reasons why the mutation failed.",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "LIST",
+                  "name": null,
+                  "ofType": {
+                    "kind": "NON_NULL",
+                    "name": null,
+                    "ofType": {
+                      "kind": "SCALAR",
+                      "name": "String",
+                      "ofType": null
+                    }
+                  }
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "issue",
+              "description": "The issue after mutation",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "OBJECT",
+                "name": "Issue",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            }
+          ],
+          "inputFields": null,
+          "interfaces": [
+
+          ],
+          "enumValues": null,
+          "possibleTypes": null
+        },
+        {
+          "kind": "INPUT_OBJECT",
+          "name": "IssueSetDueDateInput",
+          "description": "Autogenerated input type of IssueSetDueDate",
+          "fields": null,
+          "inputFields": [
+            {
+              "name": "projectPath",
+              "description": "The project the issue to mutate is in",
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "ID",
+                  "ofType": null
+                }
+              },
+              "defaultValue": null
+            },
+            {
+              "name": "iid",
+              "description": "The iid of the issue to mutate",
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "String",
+                  "ofType": null
+                }
+              },
+              "defaultValue": null
+            },
+            {
+              "name": "dueDate",
+              "description": "The desired due date for the issue",
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "Time",
+                  "ofType": null
+                }
+              },
+              "defaultValue": null
+            },
+            {
+              "name": "clientMutationId",
+              "description": "A unique identifier for the client performing the mutation.",
+              "type": {
+                "kind": "SCALAR",
+                "name": "String",
+                "ofType": null
+              },
+              "defaultValue": null
+            }
+          ],
+          "interfaces": null,
+          "enumValues": null,
+          "possibleTypes": null
+        },
         {
           "kind": "OBJECT",
           "name": "MergeRequestSetLabelsPayload",

doc/api/graphql/reference/index.md

@@ -375,6 +375,14 @@ The API can be explored interactively using the [GraphiQL IDE](../index.md#graph
 | `createDesign` | Boolean! | Whether or not a user can perform `create_design` on this resource |
 | `destroyDesign` | Boolean! | Whether or not a user can perform `destroy_design` on this resource |
 
+### IssueSetDueDatePayload
+
+| Name  | Type  | Description |
+| ---   |  ---- | ----------  |
+| `clientMutationId` | String | A unique identifier for the client performing the mutation. |
+| `errors` | String! => Array | Reasons why the mutation failed. |
+| `issue` | Issue | The issue after mutation |
+
 ### Label
 
 | Name  | Type  | Description |

spec/graphql/mutations/issues/set_due_date_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Mutations::Issues::SetDueDate do
+  let(:issue) { create(:issue) }
+  let(:user) { create(:user) }
+  subject(:mutation) { described_class.new(object: nil, context: { current_user: user }) }
+
+  describe '#resolve' do
+    let(:due_date) { 2.days.since }
+    let(:mutated_issue) { subject[:issue] }
+    subject { mutation.resolve(project_path: issue.project.full_path, iid: issue.iid, due_date: due_date) }
+
+    it 'raises an error if the resource is not accessible to the user' do
+      expect { subject }.to raise_error(Gitlab::Graphql::Errors::ResourceNotAvailable)
+    end
+
+    context 'when the user can update the issue' do
+      before do
+        issue.project.add_developer(user)
+      end
+
+      it 'returns the issue with updated due date' do
+        expect(mutated_issue).to eq(issue)
+        expect(mutated_issue.due_date).to eq(Date.today + 2.days)
+        expect(subject[:errors]).to be_empty
+      end
+
+      context 'when passing incorrect due date value' do
+        let(:due_date) { 'test' }
+
+        it 'does not update due date' do
+          expect(mutated_issue.due_date).to eq(issue.due_date)
+        end
+      end
+    end
+  end
+end

spec/requests/api/graphql/mutations/issues/set_due_date_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'Setting Due Date of an issue' do
+  include GraphqlHelpers
+
+  let(:current_user) { create(:user) }
+  let(:issue) { create(:issue) }
+  let(:project) { issue.project }
+  let(:input) { { due_date: 2.days.since } }
+
+  let(:mutation) do
+    variables = {
+      project_path: project.full_path,
+      iid: issue.iid.to_s
+    }
+    graphql_mutation(:issue_set_due_date, variables.merge(input),
+                     <<-QL.strip_heredoc
+                       clientMutationId
+                       errors
+                       issue {
+                         iid
+                         dueDate
+                       }
+                     QL
+    )
+  end
+
+  def mutation_response
+    graphql_mutation_response(:issue_set_due_date)
+  end
+
+  before do
+    project.add_developer(current_user)
+  end
+
+  it 'returns an error if the user is not allowed to update the issue' do
+    error = "The resource that you are attempting to access does not exist or you don't have permission to perform this action"
+    post_graphql_mutation(mutation, current_user: create(:user))
+
+    expect(graphql_errors).to include(a_hash_including('message' => error))
+  end
+
+  it 'updates the issue due date' do
+    post_graphql_mutation(mutation, current_user: current_user)
+
+    expect(response).to have_gitlab_http_status(:success)
+    expect(mutation_response['issue']['dueDate']).to eq(2.days.since.to_date.to_s)
+  end
+
+  context 'when passing due date without a date value' do
+    let(:input) { { due_date: 'test' } }
+
+    it 'returns internal server error' do
+      post_graphql_mutation(mutation, current_user: current_user)
+
+      expect(graphql_errors).to include(a_hash_including('message' => 'Internal server error'))
+    end
+  end
+end