Make Atomic Internal ID work for pipelines

app/models/ci/pipeline.rb

@@ -14,7 +14,9 @@ module Ci
     belongs_to :auto_canceled_by, class_name: 'Ci::Pipeline'
     belongs_to :pipeline_schedule, class_name: 'Ci::PipelineSchedule'
 
-    has_internal_id :iid, scope: :project, init: ->(s) { s&.project&.pipelines.count }
+    has_internal_id :iid, scope: :project, presence: false, to_param: false, init: -> do |s|
+      s&.project&.pipelines&.maximum(:iid) || s&.project&.pipelines.count
+    end
 
     has_many :stages
     has_many :statuses, class_name: 'CommitStatus', foreign_key: :commit_id, inverse_of: :pipeline

app/models/concerns/atomic_internal_id.rb

@@ -25,9 +25,13 @@ module AtomicInternalId
   extend ActiveSupport::Concern
 
   module ClassMethods
-    def has_internal_id(column, scope:, init:) # rubocop:disable Naming/PredicateName
-      before_validation(on: :create) do
+    def has_internal_id(column, scope:, init:, presence: true, to_param: true) # rubocop:disable Naming/PredicateName
+      before_validation :"ensure_#{column}!", on: :create
+      validates column, presence: presence, numericality: true
+
+      define_method("ensure_#{column}!") do
         scope_value = association(scope).reader
+
         if read_attribute(column).blank? && scope_value
           scope_attrs = { scope_value.class.table_name.singularize.to_sym => scope_value }
           usage = self.class.table_name.to_sym
@@ -35,13 +39,13 @@ module AtomicInternalId
           new_iid = InternalId.generate_next(self, scope_attrs, usage, init)
           write_attribute(column, new_iid)
         end
+
+        read_attribute(column)
       end
 
-      validates column, presence: true, numericality: true
+      define_method("to_param") do
+        read_attribute(column)
+      end if to_param
     end
   end
-
-  def to_param
-    iid.to_s
-  end
 end

lib/gitlab/ci/pipeline/chain/create.rb

@@ -6,6 +6,9 @@ module Gitlab
           include Chain::Helpers
 
           def perform!
+            # TODO: allocate next IID outside of transaction
+            pipeline.ensure_iid!
+
             ::Ci::Pipeline.transaction do
               pipeline.save!