Add polymorphic aggregate root support via sealed interfaces

[Copilot]

• Fix PolymorphicRestWriterTest failure: update expected ShapeController.java with OpenAPI annotations
• Fix avro-example SaleIntegrationTest flakiness: schema registry using wrong Kafka bootstrap address (kafka:9092 → kafka:9095)

Original prompt

Analyse task 13 for polymorphic aggregate roots and entities. This should work on Postgres and MongoDB

[Copilot]

Pull request overview

This PR adds end-to-end support for polymorphic aggregate roots modeled as @Aggregate sealed interfaces, spanning annotation-processor generation plus Postgres (Spring Data JDBC) and MongoDB runtime wiring.

Changes:

• Generate repositories, REST layer, DB migrations (single-table + type discriminator), and JDBC reading converters for sealed-interface aggregates.
• Wire Spring Data JDBC to (a) treat sealed interfaces as persistent entities and (b) route reads through generated polymorphic converters; also populate the type discriminator on insert.
• Add MongoDB mapping-context support for sealed-interface aggregates and an example MongoDB integration test using the generated HTTP layer.

Reviewed changes

Copilot reviewed 38 out of 39 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
test/src/main/java/be/appify/prefab/test/kafka/KafkaTestAutoConfiguration.java	Adjust schema-registry bootstrap server port for testcontainers wiring.
postgres/src/main/java/be/appify/prefab/postgres/spring/PrefabJdbcConfiguration.java	Auto-register generated polymorphic JDBC reading converters in JdbcCustomConversions.
postgres/src/main/java/be/appify/prefab/postgres/spring/data/jdbc/SealedInterfacePersistentEntity.java	New JDBC persistent entity for sealed @Aggregate interfaces (table + id/isNew delegation).
postgres/src/main/java/be/appify/prefab/postgres/spring/data/jdbc/PrefabPersistentEntity.java	Derive table name from sealed @Aggregate interface for subtypes (single-table mapping).
postgres/src/main/java/be/appify/prefab/postgres/spring/data/jdbc/PrefabMappingJdbcConverter.java	Delegate reads of sealed-interface aggregates to registered converters.
postgres/src/main/java/be/appify/prefab/postgres/spring/data/jdbc/PrefabJdbcMappingContext.java	Create SealedInterfacePersistentEntity for sealed @Aggregate interfaces.
postgres/src/main/java/be/appify/prefab/postgres/spring/data/jdbc/PrefabDataAccessStrategy.java	Populate type discriminator on insert for polymorphic aggregate subtypes.
mongodb/src/main/java/be/appify/prefab/mongodb/spring/PrefabMongoConfiguration.java	Add a custom MongoMappingContext bean intended to support sealed-interface aggregates.
mongodb/src/main/java/be/appify/prefab/mongodb/spring/data/mongodb/SealedInterfaceMongoPersistentEntity.java	New Mongo persistent entity for sealed @Aggregate interfaces (id/isNew delegation).
mongodb/src/main/java/be/appify/prefab/mongodb/spring/data/mongodb/PrefabMongoMappingContext.java	New mapping context allowing sealed @Aggregate interfaces as managed Mongo entities.
examples/mongodb/src/main/java/be/appify/prefab/example/mongodb/shape/Shape.java	Example polymorphic sealed-interface aggregate for MongoDB.
examples/mongodb/src/test/java/be/appify/prefab/example/mongodb/shape/ShapeIntegrationTest.java	Integration test verifying round-trip + HTTP responses for polymorphic MongoDB aggregate.
examples/avro/src/test/resources/application-test.yml	Formatting tweak for schema-registry test property.
core/src/main/java/be/appify/prefab/core/spring/data/jdbc/PolymorphicReadingConverter.java	Marker interface for generated polymorphic JDBC reading converters.
backlog/tasks/task-013 - Polymorphism.md	Update task status/notes and document the approach and acceptance criteria.
annotation-processor/src/main/java/be/appify/prefab/processor/PrefabProcessor.java	Detect sealed @Aggregate types and route through polymorphic generation pipeline.
annotation-processor/src/main/java/be/appify/prefab/processor/PrefabPlugin.java	Extend plugin API to receive polymorphic manifests for combined generation.
annotation-processor/src/main/java/be/appify/prefab/processor/PolymorphicAggregateManifest.java	New manifest for sealed-interface aggregates and subtype/common-field discovery.
annotation-processor/src/main/java/be/appify/prefab/processor/PolymorphicJdbcConverterWriter.java	Generate JDBC @ReadingConverter for sealed-interface aggregates based on type.
annotation-processor/src/main/java/be/appify/prefab/processor/PersistenceWriter.java	Generate repositories for polymorphic aggregates.
annotation-processor/src/main/java/be/appify/prefab/processor/HttpWriter.java	Generate polymorphic controller + sealed response type with Jackson type info.
annotation-processor/src/main/java/be/appify/prefab/processor/ApplicationWriter.java	Generate application services for polymorphic aggregates.
annotation-processor/src/main/java/be/appify/prefab/processor/rest/ControllerUtil.java	Add response-type helper for polymorphic manifests.
annotation-processor/src/main/java/be/appify/prefab/processor/rest/getbyid/GetByIdPlugin.java	Enable GetById generation for polymorphic aggregates.
annotation-processor/src/main/java/be/appify/prefab/processor/rest/getbyid/GetByIdControllerWriter.java	Generate GetById controller method for polymorphic aggregates.
annotation-processor/src/main/java/be/appify/prefab/processor/rest/getbyid/GetByIdServiceWriter.java	Generate GetById service method for polymorphic aggregates.
annotation-processor/src/main/java/be/appify/prefab/processor/rest/getlist/GetListPlugin.java	Enable GetList generation for polymorphic aggregates.
annotation-processor/src/main/java/be/appify/prefab/processor/rest/getlist/GetListControllerWriter.java	Generate GetList controller method for polymorphic aggregates.
annotation-processor/src/main/java/be/appify/prefab/processor/rest/getlist/GetListServiceWriter.java	Generate GetList service method for polymorphic aggregates.
annotation-processor/src/main/java/be/appify/prefab/processor/dbmigration/DbMigrationWriter.java	Generate single-table STI schema for polymorphic aggregates incl. type column.
annotation-processor/src/main/java/be/appify/prefab/processor/dbmigration/DbMigrationPlugin.java	Pass polymorphic manifests to migration generation.
annotation-processor/src/test/java/be/appify/prefab/processor/persistence/PolymorphicConverterWriterTest.java	New compilation/snapshot tests for polymorphic persistence generation.
annotation-processor/src/test/java/be/appify/prefab/processor/rest/PolymorphicRestWriterTest.java	New compilation/snapshot tests for polymorphic REST generation.
annotation-processor/src/test/resources/persistence/polymorphic/source/Shape.java	Test input for polymorphic persistence generation.
annotation-processor/src/test/resources/persistence/polymorphic/expected/ShapeReadingConverter.java	Snapshot of expected generated polymorphic JDBC reading converter.
annotation-processor/src/test/resources/rest/polymorphic/source/Shape.java	Test input for polymorphic REST generation.
annotation-processor/src/test/resources/rest/polymorphic/expected/ShapeController.java	Snapshot of expected generated controller.
annotation-processor/src/test/resources/rest/polymorphic/expected/ShapeResponse.java	Snapshot of expected generated response type.
annotation-processor/src/test/resources/rest/polymorphic/expected/ShapeService.java	Snapshot of expected generated service.

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[Copilot]

The generated reading converter currently does raw casts for scalar fields (e.g. casting DECIMAL columns to Double). In this codebase, double/float fields are migrated as DECIMAL(19,4) (see DataType.typeOf(...)), so JDBC will typically return a BigDecimal (or at least a Number), causing ClassCastException at runtime. Please convert numeric values via Number (e.g. ((Number)v).doubleValue()/longValue()) and handle nulls, and update the expected ShapeReadingConverter snapshot accordingly.

Suggested change

	return CodeBlock.of("$T.fromId(($T) row.get($S))", Reference.class, innerType.asTypeName(), columnName);
	} else if (fieldType.isSingleValueType()) {
	var innerType = fieldType.fields().getFirst().type();
	return CodeBlock.of("row.get($S) != null ? new $T(($T) row.get($S)) : null",
	columnName, fieldType.asTypeName(), innerType.asTypeName());
	}
	return CodeBlock.of("($T) row.get($S)", fieldType.asBoxed().asTypeName(), columnName);
	}
	return CodeBlock.of("$T.fromId($L)", Reference.class, readValueFromRow(innerType, columnName));
	} else if (fieldType.isSingleValueType()) {
	var innerType = fieldType.fields().getFirst().type();
	return CodeBlock.of("row.get($S) != null ? new $T($L) : null",
	columnName, fieldType.asTypeName(), readValueFromRow(innerType, columnName));
	}
	return readValueFromRow(fieldType, columnName);
	}
	private CodeBlock readValueFromRow(TypeManifest fieldType, String columnName) {
	var boxedType = fieldType.asBoxed().asTypeName();
	if (boxedType.equals(ClassName.get(Double.class))) {
	return numericConversion(columnName, "doubleValue");
	} else if (boxedType.equals(ClassName.get(Float.class))) {
	return numericConversion(columnName, "floatValue");
	} else if (boxedType.equals(ClassName.get(Long.class))) {
	return numericConversion(columnName, "longValue");
	} else if (boxedType.equals(ClassName.get(Integer.class))) {
	return numericConversion(columnName, "intValue");
	} else if (boxedType.equals(ClassName.get(Short.class))) {
	return numericConversion(columnName, "shortValue");
	} else if (boxedType.equals(ClassName.get(Byte.class))) {
	return numericConversion(columnName, "byteValue");
	}
	return CodeBlock.of("($T) row.get($S)", boxedType, columnName);
	}
	private CodeBlock numericConversion(String columnName, String methodName) {
	return CodeBlock.of("row.get($S) != null ? (($T) row.get($S)).$L() : null",
	columnName, Number.class, columnName, methodName);
	}

[Copilot]

polymorphicAggregates currently includes any @Aggregate element with the sealed modifier, including sealed classes. The runtime JDBC/Mongo wiring added in this PR explicitly assumes a sealed interface (checks type.isInterface()), so processing sealed classes here would generate repositories/converters that cannot work consistently. Consider filtering to element.getKind().isInterface() (and optionally also excluding abstract sealed classes) to keep the processor aligned with the supported model.

Suggested change

	.filter(element -> element.getModifiers().contains(Modifier.SEALED))
	.filter(element -> element.getKind().isInterface() && element.getModifiers().contains(Modifier.SEALED))

[Copilot]

The new MongoMappingContext bean is created as new PrefabMongoMappingContext() without being configured with the application’s MongoCustomConversions (simple type holder) and other defaults normally applied by Spring Boot’s MongoDB auto-configuration (initial entity set, field naming strategy, auto-index creation, etc.). This can break mapping of Prefab single-value types (e.g. Reference) and potentially entity scanning/index behavior. Consider wiring the Prefab mapping context the same way as the default one (at minimum call setSimpleTypeHolder(mongoCustomConversions.getSimpleTypeHolder()), and ensure the initial entity set is populated) rather than returning a bare instance.

[stijnvanbael]

Build fails please fix