transform_behaviour is a transformer

AGENTS.md

@@ -269,7 +269,7 @@ Spark runs two separate pipelines during compilation, in this order:
 - A transformer that needs to expose baked state does not need a separate persister — call `Transformer.persist/3` inline and emit the module function via `Transformer.eval/3`.
 - Do not put a transformer in `persisters:` hoping `after?` declarations will order it relative to transformers — those declarations are silently ignored across pipeline boundaries.
 
-**Current state:** `TransformBehaviour` is misregistered under `persisters:` — a known issue tracked for refactoring. New transformers go under `transformers:`.
+New transformers go under `transformers:`. New persisters go under `persisters:`.
 
 ## Raising upstream bugs
 

lib/diffo/provider/extension.ex

@@ -585,7 +585,8 @@ defmodule Diffo.Provider.Extension do
   use Spark.Dsl.Extension,
     sections: [@provider],
     transformers: [
-      Diffo.Provider.Extension.Transformers.TransformRelationships
+      Diffo.Provider.Extension.Transformers.TransformRelationships,
+      Diffo.Provider.Extension.Transformers.TransformBehaviour
     ],
     persisters: [
       Diffo.Provider.Extension.Persisters.PersistSpecification,
@@ -594,8 +595,7 @@ defmodule Diffo.Provider.Extension do
       Diffo.Provider.Extension.Persisters.PersistPools,
       Diffo.Provider.Extension.Persisters.PersistParties,
       Diffo.Provider.Extension.Persisters.PersistPlaces,
-      Diffo.Provider.Extension.Persisters.PersistInstances,
-      Diffo.Provider.Extension.Transformers.TransformBehaviour
+      Diffo.Provider.Extension.Persisters.PersistInstances
     ],
     verifiers: [
       Diffo.Provider.Extension.Verifiers.VerifySpecification,

lib/diffo/provider/extension/transformers/transform_behaviour.ex

@@ -16,12 +16,12 @@ defmodule Diffo.Provider.Extension.Transformers.TransformBehaviour do
 
   @impl true
   def transform(dsl_state) do
-    spec = Transformer.get_persisted(dsl_state, :specification, [])
+    spec_id = Transformer.get_option(dsl_state, [:provider, :specification], :id)
 
     dsl_state = inject_create_arguments(dsl_state)
 
     {build_before_body, build_after_body} =
-      if spec[:id] do
+      if spec_id do
         before_body =
           quote do
             changeset
@@ -128,12 +128,4 @@ defmodule Diffo.Provider.Extension.Transformers.TransformBehaviour do
     end)
   end
 
-  @impl true
-  def after?(Diffo.Provider.Extension.Persisters.PersistSpecification), do: true
-  def after?(Diffo.Provider.Extension.Persisters.PersistCharacteristics), do: true
-  def after?(Diffo.Provider.Extension.Persisters.PersistFeatures), do: true
-  def after?(Diffo.Provider.Extension.Persisters.PersistPools), do: true
-  def after?(Diffo.Provider.Extension.Persisters.PersistParties), do: true
-  def after?(Diffo.Provider.Extension.Persisters.PersistPlaces), do: true
-  def after?(_), do: false
 end