Feat/normalizer default propagation

[Picazsoo]

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package || exit
  ./bin/generate-samples.sh ./bin/configs/*.yaml || exit
  ./bin/utils/export_docs_generators.sh || exit
  

  (For Windows users, please run the script in WSL)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• File the PR against the correct branch: master (upcoming 7.x.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
• If your PR solves a reported issue, reference it using GitHub's linking syntax (e.g., having "fixes #123" present in the PR description)
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

---

Summary by cubic

Introduces a configurable DefaultResolutionStrategy to resolve default values in allOf schemas and makes $ref defaults reliably visible to generators by pre-resolving refs in DefaultCodegen.fromProperty. Also adds an opt-in normalizer rule RESOLVE_SCHEMA_DEFAULTS to write resolved defaults back to schemas.

• New Features

  • ModelUtils.resolveDefault() with strategies: LAST_WINS, NEAREST_WINS, ROOT_WINS, STRICT (see docs/default-resolution-strategy.md).
  • Normalizer flag RESOLVE_SCHEMA_DEFAULTS=<strategy> resolves and applies default to component/property schemas; skips pure $ref to keep OAS validity.
  • Lint recommendations for allOf conflicts and shadowed defaults in OpenApiSchemaValidations.

• Refactors

  • $ref default propagation moved to DefaultCodegen.fromProperty (deep $ref traversal); removed redundant ref resolution in AbstractJavaCodegen/AbstractKotlinCodegen; restored follow-ref in AbstractPythonCodegen.toDefaultValue(Schema) for direct calls.
  • C++: ensure model members are default-constructed (CppHttplibServerCodegen, CppTinyClientCodegen, CppTizenClientCodegen).
  • Added tests and refreshed samples; generated C# docs now display enum defaults.

^{Written for commit 6177051. Summary will update on new commits. Review in cubic}

[cubic-dev-ai]

3 issues found across 141 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/client/petstore/csharp/generichost/net10/NullReferenceTypes/src/Org.OpenAPITools/Model/EnumTest.cs">

<violation number="1" location="samples/client/petstore/csharp/generichost/net10/NullReferenceTypes/src/Org.OpenAPITools/Model/EnumTest.cs:43">
P2: Constructor XML docs claim enum defaults are applied, but the constructor passes through `Option<T> = default` without applying them, creating a doc/behavior mismatch.</violation>
</file>

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

<violation number="1" location="modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java:348">
P1: RESOLVE_SCHEMA_DEFAULTS rule can be enabled with a null strategy when the user provides an invalid value (e.g. `true`), leading to a NullPointerException at runtime in ModelUtils.resolveDefault</violation>

<violation number="2" location="modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java:670">
P1: Component schemas which are pure $ref may get a sibling `default` written, creating an invalid OAS 3.0 Reference Object. The `normalizeComponentsSchemas()` method resolves and writes defaults back onto normalized component schemas without checking whether the schema is a pure `$ref`, unlike the property-level normalization which correctly skips pure `$ref` schemas to avoid invalid OAS 3.0 Reference Objects.</violation>
</file>

<sub>Note: This PR contains a large number of files. cubic only reviews up to 100 files per PR, so some files may not have been reviewed. cubic prioritizes the most important files to review.
On a pro plan you can use ultrareview for larger PRs.

Re-trigger cubic</sub>

[cubic-dev-ai]

P1: Component schemas which are pure $ref may get a sibling default written, creating an invalid OAS 3.0 Reference Object. The normalizeComponentsSchemas() method resolves and writes defaults back onto normalized component schemas without checking whether the schema is a pure $ref, unlike the property-level normalization which correctly skips pure $ref schemas to avoid invalid OAS 3.0 Reference Objects.

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/OpenAPINormalizer.java, line 670:

<comment>Component schemas which are pure $ref may get a sibling `default` written, creating an invalid OAS 3.0 Reference Object. The `normalizeComponentsSchemas()` method resolves and writes defaults back onto normalized component schemas without checking whether the schema is a pure `$ref`, unlike the property-level normalization which correctly skips pure `$ref` schemas to avoid invalid OAS 3.0 Reference Objects.</comment>

<file context>
@@ -643,7 +662,17 @@ protected void normalizeComponentsSchemas() {
+
+                // if RESOLVE_SCHEMA_DEFAULTS is enabled, compute and write back the effective
+                // default for allOf-composed component schemas that have no direct default.
+                if (getRule(RESOLVE_SCHEMA_DEFAULTS) && normalizedSchema.getDefault() == null) {
+                    Object resolved = ModelUtils.resolveDefault(openAPI, normalizedSchema, resolveSchemaDefaultsStrategy);
+                    if (resolved != null) {
</file context>

[cubic-dev-ai]

P1: RESOLVE_SCHEMA_DEFAULTS rule can be enabled with a null strategy when the user provides an invalid value (e.g. true), leading to a NullPointerException at runtime in ModelUtils.resolveDefault

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/OpenAPINormalizer.java, line 348:

<comment>RESOLVE_SCHEMA_DEFAULTS rule can be enabled with a null strategy when the user provides an invalid value (e.g. `true`), leading to a NullPointerException at runtime in ModelUtils.resolveDefault</comment>

<file context>
@@ -329,6 +338,16 @@ public void processRules(Map<String, String> inputRules) {
+                resolveSchemaDefaultsStrategy = DefaultResolutionStrategy.valueOf(resolveSchemaDefaultsValue.trim().toUpperCase(java.util.Locale.ROOT));
+                rules.put(RESOLVE_SCHEMA_DEFAULTS, true);
+            } catch (IllegalArgumentException e) {
+                LOGGER.error("RESOLVE_SCHEMA_DEFAULTS rule must be one of LAST_WINS, NEAREST_WINS, ROOT_WINS, STRICT. Got: {}", resolveSchemaDefaultsValue);
+            }
+        }
</file context>

Suggested change

	LOGGER.error("RESOLVE_SCHEMA_DEFAULTS rule must be one of LAST_WINS, NEAREST_WINS, ROOT_WINS, STRICT. Got: {}", resolveSchemaDefaultsValue);
	LOGGER.error("RESOLVE_SCHEMA_DEFAULTS rule must be one of LAST_WINS, NEAREST_WINS, ROOT_WINS, STRICT. Got: {}", resolveSchemaDefaultsValue);
	rules.put(RESOLVE_SCHEMA_DEFAULTS, false);

[cubic-dev-ai]

P2: Constructor XML docs claim enum defaults are applied, but the constructor passes through Option<T> = default without applying them, creating a doc/behavior mismatch.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/client/petstore/csharp/generichost/net10/NullReferenceTypes/src/Org.OpenAPITools/Model/EnumTest.cs, line 43:

<comment>Constructor XML docs claim enum defaults are applied, but the constructor passes through `Option<T> = default` without applying them, creating a doc/behavior mismatch.</comment>

<file context>
@@ -40,9 +40,9 @@ public partial class EnumTest : IValidatableObject
         /// <param name="enumString">enumString</param>
         /// <param name="outerEnum">outerEnum</param>
-        /// <param name="outerEnumDefaultValue">outerEnumDefaultValue</param>
+        /// <param name="outerEnumDefaultValue">outerEnumDefaultValue (default to OuterEnumDefaultValue.Placed)</param>
         /// <param name="outerEnumInteger">outerEnumInteger</param>
-        /// <param name="outerEnumIntegerDefaultValue">outerEnumIntegerDefaultValue</param>
</file context>