[dart-dio][built_value] Register BuilderFactory for nested additionalProperties shapes

[wing328]

based on #23662 with resolved merge conflicts

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---

Summary by cubic

Fixes missing builder factories for nested additionalProperties in Dart dart-dio built_value serializers. Prevents runtime errors like "Bad state: No builder factory for BuiltList" for shapes such as Map<String, List>.

• Bug Fixes
  • Walk container trees and register builder factories for each nested layer (e.g., Map<String, List>, List<Map<String, X>>).
  • Add composite serializer support in serializers.mustache to emit nested FullType(...) and matching builders.
  • Extend BuiltValueSerializer with a composite mode and proper dedup via equals/hashCode.
  • Add regression test and fixture covering Map<String, List<$ref>>; update generated petstore samples.

^{Written for commit a7187d1. Summary will update on new commits.}

[cubic-dev-ai]

2 issues found across 6 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/src/serializers.dart">

<violation number="1" location="samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/src/serializers.dart:204">
P1: Builder type mismatch: FullType.nullable(JsonObject) means list elements are JsonObject?, but ListBuilder<JsonObject> rejects nulls. At runtime, deserializing a list with null elements would throw.</violation>
</file>

<file name="modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartDioClientCodegen.java">

<violation number="1" location="modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartDioClientCodegen.java:730">
P2: Nested composite builder-factory generation drops `isNullable` information, so nullable nested container/value types are registered as non-nullable and can deserialize incorrectly.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

P1: Builder type mismatch: FullType.nullable(JsonObject) means list elements are JsonObject?, but ListBuilder rejects nulls. At runtime, deserializing a list with null elements would throw.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/src/serializers.dart, line 204:

<comment>Builder type mismatch: FullType.nullable(JsonObject) means list elements are JsonObject?, but ListBuilder<JsonObject> rejects nulls. At runtime, deserializing a list with null elements would throw.</comment>

<file context>
@@ -153,21 +193,45 @@ Serializers serializers = (_$serializers.toBuilder()
         () => ListBuilder<ModelEnumClass>(),
       )
+      ..addBuilderFactory(
+        const FullType(BuiltList, [FullType.nullable(JsonObject)]),
+        () => ListBuilder<JsonObject>(),
+      )
</file context>

Suggested change

	const FullType(BuiltList, [FullType.nullable(JsonObject)]),
	() => ListBuilder<JsonObject>(),
	const FullType(BuiltList, [FullType.nullable(JsonObject)]),
	() => ListBuilder<JsonObject?>(),

[cubic-dev-ai]

P2: Nested composite builder-factory generation drops isNullable information, so nullable nested container/value types are registered as non-nullable and can deserialize incorrectly.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartDioClientCodegen.java, line 730:

<comment>Nested composite builder-factory generation drops `isNullable` information, so nullable nested container/value types are registered as non-nullable and can deserialize incorrectly.</comment>

<file context>
@@ -661,10 +661,134 @@ public void postProcessModelProperty(CodegenModel model, CodegenProperty propert
+            String collection = prop.getUniqueItems() ? "BuiltSet" : "BuiltList";
+            String builder = prop.getUniqueItems() ? "SetBuilder" : "ListBuilder";
+            return new BuilderFactoryExpr(
+                    collection + ", [FullType(" + innerFullType + ")]",
+                    builder + "<" + innerDart + ">");
+        }
</file context>