Add support for Git push options, specifically ci.skip

gitlab-org/gitlab-shell!166 added support for collecting push options
from the environment, and passing them along to the
/internal/post_receive API endpoint.

This change handles the new push_options JSON element in the payload,
and passes them on through to the GitPushService and GitTagPushService
services.

Futhermore, it adds support for the first push option, ci.skip.  With
this change, one can use 'git push -o ci.skip' to skip CI pipe
execution. Note that the pipeline is still created, but in the "skipped"
state, just like with the 'ci skip' commit message text.

Implements #18667

5 files changed, 22 insertions, 8 deletions

diff --git a/lib/api/internal.rb b/lib/api/internal.rb
index ae40b5f7557..9488b3469d9 100644
--- a/lib/api/internal.rb
+++ b/lib/api/internal.rb
@@ -256,8 +256,9 @@ module API
 
       post '/post_receive' do
         status 200
+
         PostReceive.perform_async(params[:gl_repository], params[:identifier],
-          params[:changes])
+          params[:changes], params[:push_options].to_a)
         broadcast_message = BroadcastMessage.current&.last&.message
         reference_counter_decreased = Gitlab::ReferenceCounter.new(params[:gl_repository]).decrease
 
diff --git a/lib/gitlab/ci/pipeline/chain/command.rb b/lib/gitlab/ci/pipeline/chain/command.rb
index 100b9521412..b9fd46bccc2 100644
--- a/lib/gitlab/ci/pipeline/chain/command.rb
+++ b/lib/gitlab/ci/pipeline/chain/command.rb
@@ -10,7 +10,7 @@ module Gitlab
           :origin_ref, :checkout_sha, :after_sha, :before_sha,
           :trigger_request, :schedule, :merge_request,
           :ignore_skip_ci, :save_incompleted,
-          :seeds_block, :variables_attributes
+          :seeds_block, :variables_attributes, :push_options
         ) do
           include Gitlab::Utils::StrongMemoize
 
diff --git a/lib/gitlab/ci/pipeline/chain/skip.rb b/lib/gitlab/ci/pipeline/chain/skip.rb
index b9707d2f8f5..79bbcc1ed1e 100644
--- a/lib/gitlab/ci/pipeline/chain/skip.rb
+++ b/lib/gitlab/ci/pipeline/chain/skip.rb
@@ -8,6 +8,7 @@ module Gitlab
           include ::Gitlab::Utils::StrongMemoize
 
           SKIP_PATTERN = /\[(ci[ _-]skip|skip[ _-]ci)\]/i
+          SKIP_PUSH_OPTION = 'ci.skip'
 
           def perform!
             if skipped?
@@ -16,7 +17,7 @@ module Gitlab
           end
 
           def skipped?
-            !@command.ignore_skip_ci && commit_message_skips_ci?
+            !@command.ignore_skip_ci && (commit_message_skips_ci? || push_option_skips_ci?)
           end
 
           def break?
@@ -32,6 +33,10 @@ module Gitlab
               !!(@pipeline.git_commit_message =~ SKIP_PATTERN)
             end
           end
+
+          def push_option_skips_ci?
+            !!(@command.push_options&.include?(SKIP_PUSH_OPTION))
+          end
         end
       end
     end
diff --git a/lib/gitlab/data_builder/push.rb b/lib/gitlab/data_builder/push.rb
index 9bf2f9291a8..862127110b9 100644
--- a/lib/gitlab/data_builder/push.rb
+++ b/lib/gitlab/data_builder/push.rb
@@ -31,7 +31,11 @@ module Gitlab
               }
             }
           ],
-          total_commits_count: 1
+          total_commits_count: 1,
+          push_options: [
+            "ci.skip",
+            "custom option"
+          ]
         }.freeze
 
       # Produce a hash of post-receive data
@@ -52,10 +56,12 @@ module Gitlab
       #     homepage: String,
       #   },
       #   commits: Array,
-      #   total_commits_count: Fixnum
+      #   total_commits_count: Fixnum,
+      #   push_options: Array
       # }
       #
-      def build(project, user, oldrev, newrev, ref, commits = [], message = nil, commits_count: nil)
+      # rubocop:disable Metrics/ParameterLists
+      def build(project, user, oldrev, newrev, ref, commits = [], message = nil, commits_count: nil, push_options: [])
         commits = Array(commits)
 
         # Total commits count
@@ -93,6 +99,7 @@ module Gitlab
           project: project.hook_attrs,
           commits: commit_attrs,
           total_commits_count: commits_count,
+          push_options: push_options,
           # DEPRECATED
           repository: project.hook_attrs.slice(:name, :url, :description, :homepage,
                                                :git_http_url, :git_ssh_url, :visibility_level)
diff --git a/lib/gitlab/git_post_receive.rb b/lib/gitlab/git_post_receive.rb
index cf2329e489d..426436c2164 100644
--- a/lib/gitlab/git_post_receive.rb
+++ b/lib/gitlab/git_post_receive.rb
@@ -3,12 +3,13 @@
 module Gitlab
   class GitPostReceive
     include Gitlab::Identifier
-    attr_reader :project, :identifier, :changes
+    attr_reader :project, :identifier, :changes, :push_options
 
-    def initialize(project, identifier, changes)
+    def initialize(project, identifier, changes, push_options)
       @project = project
       @identifier = identifier
       @changes = deserialize_changes(changes)
+      @push_options = push_options
     end
 
     def identify