[java-spring;kotlin-spring] - feature: validate Pageable params [size, page, sort] and preserve defaults; Add 'autoXSpringPaginated' to java-spring

[Picazsoo]

The idea behind this PR is the fact that currently when page, size, sort are substituted with Pageable, then the default values for page, size, sort are lost and Pageable defaults to global spring defaults (size = 10; page = 0). The native spring annotation @PageableDefault makes it possible to respect the defaults specified in the api spec. Native spring annotation @SortDefault.SortDefaults(...) on the other hand preserves the sort default value if it exists.

Another issue stemming from conversion of page, size, sort to Pageableis the loss of query param validations. This PR implements two custom validators (@ValidPageable and @ValidSort) that verify the validity of the passed values and fail if the values are out of spec. These validators should be easily replaceable with custom implementations via importMapping - this might be useful if one has some non-standard sort params and wants to handle the validation in a specific way.

So all together this PR makes sure that the convenience provided by conversion from separate query params page, size, sort to Pageable does not result in less strict contract in the generated api.

Some of the logic is extracted to separate class on purpose. Since I would like to implement this also in java-spring generator for feature parity.

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---

Summary by cubic

Adds validation for Spring Pageable params (page, size, sort) in Kotlin and Java generators and keeps spec defaults when converting to Pageable. Auto-detects pageable operations, adds @PageableDefault for defaults, and includes spring-boot-starter-validation when useBeanValidation=true.

• New Features

  • Options generateSortValidation and generatePageableConstraintValidation (with useBeanValidation=true, library=spring-boot) generate @ValidSort and @ValidPageable under your configPackage for Kotlin and Java.
  • autoXSpringPaginated detects page/size/sort (unless x-spring-paginated: false) and injects @PageableDefault(page = 0, size = 20) when defaults are missing.
  • Validation: @ValidSort(allowedValues=[...]) from enum (inline or $ref), works with exploded and non‑exploded arrays; @ValidPageable(maxSize=..., maxPage=...) from maximum on size/page.
  • Docs updated (spring, kotlin-spring, java-camel); new samples added for Kotlin samples/server/petstore/kotlin-springboot-sort-validation and Spring samples/server/petstore/springboot-sort-validation; CI builds updated for both.

• Migration

  • Enable with generateSortValidation: "true" and/or generatePageableConstraintValidation: "true", plus useBeanValidation: "true" and library: spring-boot (optionally autoXSpringPaginated: "true").
  • Define enum values on sort and set maximum on page/size. @ValidSort/@ValidPageable are generated under your configPackage.
  • Use useBeanValidation (not beanValidations) in configs/CLI. @PageableDefault(page = 0, size = 20) is added when pageable defaults are missing.

^{Written for commit 6be3da3. Summary will update on new commits.}

[Picazsoo]

@PageableDefault(page = 0, size = 20) is now added automatically for paginated operations without explicit page/size.

This is not true - the defaults are set only when they are specified in API. When not specified, they do not appear (and basically fall back to the spring defaults which are typically page = 0, size = 10. But no annotation is needed for that). Right @cubic-dev-ai ?

[cubic-dev-ai]

1 issue found across 37 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/server/petstore/kotlin-springboot-sort-validation/pom.xml">

<violation number="1" location="samples/server/petstore/kotlin-springboot-sort-validation/pom.xml:133">
P2: Validation runtime provider is missing in Maven config; only Bean Validation API is declared, so custom `@ValidSort` constraints may not execute.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

2 issues found across 24 files (changes from recent commits).

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/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/configuration/ValidPageable.java">

<violation number="1" location="samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/configuration/ValidPageable.java:72">
P2: Validator does not handle `Pageable.unpaged()` before calling `getPageSize()`/`getPageNumber()`, which can throw and break request validation flow.</violation>
</file>

<file name="samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/RFC3339DateFormat.java">

<violation number="1" location="samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/RFC3339DateFormat.java:36">
P2: `clone()` returns `this` instead of a cloned object, creating shared-instance behavior that breaks expected `DateFormat` clone semantics and can cause state-sharing/thread-safety problems.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: Validator does not handle Pageable.unpaged() before calling getPageSize()/getPageNumber(), which can throw and break request validation flow.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/configuration/ValidPageable.java, line 72:

<comment>Validator does not handle `Pageable.unpaged()` before calling `getPageSize()`/`getPageNumber()`, which can throw and break request validation flow.</comment>

<file context>
@@ -0,0 +1,95 @@
+            boolean valid = true;
+            context.disableDefaultConstraintViolation();
+
+            if (maxSize >= 0 && pageable.getPageSize() > maxSize) {
+                context.buildConstraintViolationWithTemplate(
+                                context.getDefaultConstraintMessageTemplate()
</file context>

[cubic-dev-ai]

P2: clone() returns this instead of a cloned object, creating shared-instance behavior that breaks expected DateFormat clone semantics and can cause state-sharing/thread-safety problems.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/RFC3339DateFormat.java, line 36:

<comment>`clone()` returns `this` instead of a cloned object, creating shared-instance behavior that breaks expected `DateFormat` clone semantics and can cause state-sharing/thread-safety problems.</comment>

<file context>
@@ -0,0 +1,38 @@
+
+  @Override
+  public Object clone() {
+    return this;
+  }
+}
</file context>