[Fix #1573] Throw proper exception when there is validation error

[fjtirado]

Fix #1573

Also set the proper status when output validation or filtering fails.

[Copilot]

Pull request overview

This PR addresses #1573 by changing schema validation failures (input/output/context) to produce a spec-aligned WorkflowException carrying a standard Validation error type and status, instead of throwing arbitrary Java exceptions. It also adjusts workflow/task execution paths to propagate validation failures consistently.

Changes:

• Add standard VALIDATION error type (Errors.VALIDATION) with HTTP status 400.
• Refactor schema validation to return an optional WorkflowError.Builder (via SchemaValidator + new AbstractSchemaValidator) and throw WorkflowException at call sites when validation fails.
• Update execution paths and tests to expect/propagate WorkflowException for schema validation errors.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
types/src/main/java/io/serverlessworkflow/types/Errors.java	Adds standard VALIDATION error type/status.
impl/validation/src/main/java/io/serverlessworkflow/impl/jackson/schema/JsonSchemaValidator.java	Refactors JSON-schema validator to fit new AbstractSchemaValidator contract.
impl/test/src/test/java/io/serverlessworkflow/impl/test/HTTPWorkflowDefinitionTest.java	Updates test to assert WorkflowException and Validation error metadata.
impl/core/src/main/java/io/serverlessworkflow/impl/WorkflowUtils.java	Adds helper to throw WorkflowException from validation results and set error instance.
impl/core/src/main/java/io/serverlessworkflow/impl/WorkflowMutableInstance.java	Routes workflow output filtering/validation through the new validation error mechanism.
impl/core/src/main/java/io/serverlessworkflow/impl/WorkflowDefinition.java	Validates workflow input using the new validation error mechanism.
impl/core/src/main/java/io/serverlessworkflow/impl/WorkflowApplication.java	Updates “no validation” schema validator to new SchemaValidator signature.
impl/core/src/main/java/io/serverlessworkflow/impl/schema/SchemaValidator.java	Changes schema validator API to return optional WorkflowError.Builder.
impl/core/src/main/java/io/serverlessworkflow/impl/schema/AbstractSchemaValidator.java	Introduces common validation wrapper that maps validation messages to WorkflowError.
impl/core/src/main/java/io/serverlessworkflow/impl/executors/AbstractTaskExecutor.java	Throws WorkflowException for task input/output/context schema validation failures.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (2)

impl/core/src/main/java/io/serverlessworkflow/impl/schema/AbstractSchemaValidator.java:41

• AbstractSchemaValidator still throws an IllegalArgumentException when the model cannot be converted to the validation class. This bypasses the new validation-error path (WorkflowException/WorkflowError) and can surface as an arbitrary Java exception (and a 500) instead of the standard validation error.

                .orElseThrow(
                    () ->
                        new IllegalStateException(
                            "Model cannot be converted to proper schema validation class "
                                + validationClass)));

impl/test/src/test/java/io/serverlessworkflow/impl/test/HTTPWorkflowDefinitionTest.java:379

• The test name still says it throws an IllegalArgumentException, but the assertion now expects a WorkflowException with a validation WorkflowError.

  void testWrongSchema_should_throw_exception() {

[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

impl/core/src/main/java/io/serverlessworkflow/impl/schema/SchemaValidator.java:24

• Changing SchemaValidator.validate from void to Optional<WorkflowError.Builder> is a source/binary breaking change for any third-party SchemaValidator implementations returned from SchemaValidatorFactory (loaded via ServiceLoader). If this library intends to keep SPI compatibility in patch/minor releases, consider introducing a new method/interface for the richer return type (and keep the old void validate(WorkflowModel) contract as-is/deprecated) rather than changing the existing signature.

public interface SchemaValidator {
  Optional<WorkflowError.Builder> validate(WorkflowModel model);
}