Adds docs and schema

* Also refactors a spec
* Adds a changelog

changelogs/unreleased/lm-be-pipeline-mutations.yml

+---
+title: 'GraphQL: Pipeline mutations for retry, cancel, and destroy'
+merge_request: 39780
+author:
+type: added

doc/api/graphql/reference/gitlab_schema.graphql

@@ -9760,6 +9760,9 @@ type Mutation {
   """
   mergeRequestUpdate(input: MergeRequestUpdateInput!): MergeRequestUpdatePayload
   namespaceIncreaseStorageTemporarily(input: NamespaceIncreaseStorageTemporarilyInput!): NamespaceIncreaseStorageTemporarilyPayload
+  pipelineCancel(input: PipelineCancelInput!): PipelineCancelPayload
+  pipelineDestroy(input: PipelineDestroyInput!): PipelineDestroyPayload
+  pipelineRetry(input: PipelineRetryInput!): PipelineRetryPayload
   removeAwardEmoji(input: RemoveAwardEmojiInput!): RemoveAwardEmojiPayload @deprecated(reason: "Use awardEmojiRemove. Deprecated in 13.2")
   removeProjectFromSecurityDashboard(input: RemoveProjectFromSecurityDashboardInput!): RemoveProjectFromSecurityDashboardPayload
   runDastScan(input: RunDASTScanInput!): RunDASTScanPayload
@@ -10554,6 +10557,31 @@ type Pipeline {
   userPermissions: PipelinePermissions!
 }
 
+"""
+Autogenerated input type of PipelineCancel
+"""
+input PipelineCancelInput {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+}
+
+"""
+Autogenerated return type of PipelineCancel
+"""
+type PipelineCancelPayload {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Errors encountered during execution of the mutation.
+  """
+  errors: [String!]!
+}
+
 enum PipelineConfigSourceEnum {
   AUTO_DEVOPS_SOURCE
   BRIDGE_SOURCE
@@ -10590,6 +10618,41 @@ type PipelineConnection {
   pageInfo: PageInfo!
 }
 
+"""
+Autogenerated input type of PipelineDestroy
+"""
+input PipelineDestroyInput {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  The id of the pipeline to mutate
+  """
+  id: ID!
+}
+
+"""
+Autogenerated return type of PipelineDestroy
+"""
+type PipelineDestroyPayload {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Errors encountered during execution of the mutation.
+  """
+  errors: [String!]!
+
+  """
+  The pipeline after mutation
+  """
+  pipeline: Pipeline
+}
+
 """
 An edge in a connection.
 """
@@ -10622,6 +10685,41 @@ type PipelinePermissions {
   updatePipeline: Boolean!
 }
 
+"""
+Autogenerated input type of PipelineRetry
+"""
+input PipelineRetryInput {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  The id of the pipeline to mutate
+  """
+  id: ID!
+}
+
+"""
+Autogenerated return type of PipelineRetry
+"""
+type PipelineRetryPayload {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  Errors encountered during execution of the mutation.
+  """
+  errors: [String!]!
+
+  """
+  The pipeline after mutation
+  """
+  pipeline: Pipeline
+}
+
 enum PipelineStatusEnum {
   CANCELED
   CREATED

doc/api/graphql/reference/index.md

@@ -1622,6 +1622,25 @@ Information about pagination in a connection.
 | `user` | User | Pipeline user |
 | `userPermissions` | PipelinePermissions! | Permissions for the current user on the resource |
 
+## PipelineCancelPayload
+
+Autogenerated return type of PipelineCancel
+
+| Name  | Type  | Description |
+| ---   |  ---- | ----------  |
+| `clientMutationId` | String | A unique identifier for the client performing the mutation. |
+| `errors` | String! => Array | Errors encountered during execution of the mutation. |
+
+## PipelineDestroyPayload
+
+Autogenerated return type of PipelineDestroy
+
+| Name  | Type  | Description |
+| ---   |  ---- | ----------  |
+| `clientMutationId` | String | A unique identifier for the client performing the mutation. |
+| `errors` | String! => Array | Errors encountered during execution of the mutation. |
+| `pipeline` | Pipeline | The pipeline after mutation |
+
 ## PipelinePermissions
 
 | Name  | Type  | Description |
@@ -1630,6 +1649,16 @@ Information about pagination in a connection.
 | `destroyPipeline` | Boolean! | Indicates the user can perform `destroy_pipeline` on this resource |
 | `updatePipeline` | Boolean! | Indicates the user can perform `update_pipeline` on this resource |
 
+## PipelineRetryPayload
+
+Autogenerated return type of PipelineRetry
+
+| Name  | Type  | Description |
+| ---   |  ---- | ----------  |
+| `clientMutationId` | String | A unique identifier for the client performing the mutation. |
+| `errors` | String! => Array | Errors encountered during execution of the mutation. |
+| `pipeline` | Pipeline | The pipeline after mutation |
+
 ## Project
 
 | Name  | Type  | Description |

spec/requests/api/graphql/mutations/ci/pipeline_destroy_spec.rb

@@ -5,8 +5,8 @@ require 'spec_helper'
 RSpec.describe 'PipelineDestroy' do
   include GraphqlHelpers
 
-  let_it_be(:user) { create(:user) }
   let_it_be(:project) { create(:project) }
+  let_it_be(:user) { project.owner }
   let(:pipeline) { create(:ci_pipeline, :success, project: project, user: user) }
 
   let(:mutation) do
@@ -20,12 +20,6 @@ RSpec.describe 'PipelineDestroy' do
     )
   end
 
-  let(:mutation_response) { graphql_mutation_response(:pipeline_destroy) }
-
-  before do
-    project.add_maintainer(user)
-  end
-
   it 'returns an error if the user is not allowed to destroy the pipeline' do
     post_graphql_mutation(mutation, current_user: create(:user))
 
@@ -36,5 +30,6 @@ RSpec.describe 'PipelineDestroy' do
     post_graphql_mutation(mutation, current_user: user)
 
     expect(response).to have_gitlab_http_status(:success)
+    expect { pipeline.reload }.to raise_error(ActiveRecord::RecordNotFound)
   end
 end