1 files changed, 13 insertions, 0 deletions
diff --git a/app/services/ci/create_downstream_pipeline_service.rb b/app/services/ci/create_downstream_pipeline_service.rb
index c68d990ae2e..25cc9045052 100644
--- a/app/services/ci/create_downstream_pipeline_service.rb
+++ b/app/services/ci/create_downstream_pipeline_service.rb
@@ -11,6 +11,7 @@ module Ci
     DuplicateDownstreamPipelineError = Class.new(StandardError)
 
     MAX_NESTED_CHILDREN = 2
+    MAX_HIERARCHY_SIZE  = 1000
 
     def execute(bridge)
       @bridge = bridge
@@ -86,6 +87,11 @@ module Ci
         return false
       end
 
+      if Feature.enabled?(:ci_limit_complete_hierarchy_size) && pipeline_tree_too_large?
+        @bridge.drop!(:reached_max_pipeline_hierarchy_size)
+        return false
+      end
+
       unless can_create_downstream_pipeline?(target_ref)
         @bridge.drop!(:insufficient_bridge_permissions)
         return false
@@ -141,6 +147,13 @@ module Ci
       ancestors_of_new_child.count > MAX_NESTED_CHILDREN
     end
 
+    def pipeline_tree_too_large?
+      return false unless @bridge.triggers_downstream_pipeline?
+
+      # Applies to the entire pipeline tree across all projects
+      @bridge.pipeline.complete_hierarchy_count >= MAX_HIERARCHY_SIZE
+    end
+
     def config_checksum(pipeline)
       [pipeline.project_id, pipeline.ref, pipeline.source].hash
     end