Add auto_cancel_pending_pipelines to project API

doc/api/projects.md

@@ -735,6 +735,7 @@ POST /projects
 | `printing_merge_request_link_enabled` | boolean | no | Show link to create/view merge request when pushing from the command line |
 | `build_git_strategy` | string | no | The Git strategy. Defaults to `fetch` |
 | `build_timeout` | integer | no | The maximum amount of time in minutes that a job is able run (in seconds) |
+| `auto_cancel_pending_pipelines` | string | no | Auto-cancel pending pipelines (Note: this is not a boolean, but enabled/disabled |
 | `build_coverage_regex` | string | no | Test coverage parsing |
 | `ci_config_path` | string | no | The path to CI config file |
 | `repository_storage` | string | no | Which storage shard the repository is on. Available only to admins |
@@ -789,6 +790,7 @@ POST /projects/user/:user_id
 | `printing_merge_request_link_enabled` | boolean | no | Show link to create/view merge request when pushing from the command line |
 | `build_git_strategy` | string | no | The Git strategy. Defaults to `fetch` |
 | `build_timeout` | integer | no | The maximum amount of time in minutes that a job is able run (in seconds) |
+| `auto_cancel_pending_pipelines` | string | no | Auto-cancel pending pipelines (Note: this is not a boolean, but enabled/disabled |
 | `build_coverage_regex` | string | no | Test coverage parsing |
 | `ci_config_path` | string | no | The path to CI config file |
 | `repository_storage` | string | no | Which storage shard the repository is on. Available only to admins |
@@ -842,6 +844,7 @@ PUT /projects/:id
 | `avatar`    | mixed   | no      | Image file for avatar of the project                |
 | `build_git_strategy` | string | no | The Git strategy. Defaults to `fetch` |
 | `build_timeout` | integer | no | The maximum amount of time in minutes that a job is able run (in seconds) |
+| `auto_cancel_pending_pipelines` | string | no | Auto-cancel pending pipelines (Note: this is not a boolean, but enabled/disabled |
 | `build_coverage_regex` | string | no | Test coverage parsing |
 | `ci_config_path` | string | no | The path to CI config file |
 | `ci_default_git_depth` | integer | no | Default number of revisions for [shallow cloning](../user/project/pipelines/settings.md#git-shallow-clone) |

lib/api/entities.rb

@@ -279,6 +279,7 @@ module API
         project.build_allow_git_fetch ? 'fetch' : 'clone'
       end
       expose :build_timeout
+      expose :auto_cancel_pending_pipelines
       expose :build_coverage_regex
       expose :ci_config_path, if: -> (project, options) { Ability.allowed?(options[:current_user], :download_code, project) }
       expose :shared_with_groups do |project, options|

lib/api/helpers/projects_helpers.rb

@@ -10,6 +10,7 @@ module API
         optional :description, type: String, desc: 'The description of the project'
         optional :build_git_strategy, type: String, values: %w(fetch clone), desc: 'The Git strategy. Defaults to `fetch`'
         optional :build_timeout, type: Integer, desc: 'Build timeout'
+        optional :auto_cancel_pending_pipelines, type: String, values: %w(disabled enabled), desc: 'Auto-cancel pending pipelines'
         optional :build_coverage_regex, type: String, desc: 'Test coverage parsing'
         optional :ci_config_path, type: String, desc: 'The path to CI config file. Defaults to `.gitlab-ci.yml`'
 
@@ -61,6 +62,7 @@ module API
 
       def self.update_params_at_least_one_of
         [
+          :auto_cancel_pending_pipelines,
           :build_coverage_regex,
           :build_git_strategy,
           :build_timeout,