Map Symfony Validator constraint violations to HTTP 422 (RFC 7807)

[stixx]

Summary by CodeRabbit

Release Notes

• Bug Fixes
  • Command validation errors now return HTTP 422 (Unprocessable Entity) status code instead of HTTP 400, providing more semantically accurate error responses for failed validation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: ea7323e8-2b1e-4f15-b206-112a607713c6

📥 Commits

Reviewing files that changed from the base of the PR and between 457c0dd and b601667.

📒 Files selected for processing (6)

• src/Controller/CommandController.php
• src/Exception/ApiProblemException.php
• src/Exception/DefaultExceptionToApiProblemTransformer.php
• tests/Functional/ScenarioTest.php
• tests/Unit/Controller/CommandControllerTest.php
• tests/Unit/Exception/ApiProblemExceptionTest.php

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Walkthrough

This PR updates validation error responses from HTTP 400 (Bad Request) to HTTP 422 (Unprocessable Entity). A new ApiProblemException::unprocessableEntity() factory method is introduced to construct 422 responses, the title mapping is added to the transformer, the controller integrates the new method, and all tests are updated to verify the corrected status code.

Changes

HTTP 422 Validation Error Status Codes

Layer / File(s)	Summary
Exception API and Title Mapping src/Exception/ApiProblemException.php, src/Exception/DefaultExceptionToApiProblemTransformer.php	New unprocessableEntity() static factory accepts optional title (defaults to "The request body could not be processed"), optional detail, and violations (array or ConstraintViolationListInterface). Title transformer maps HTTP 422 to "Unprocessable Entity".
Command Validation Implementation src/Controller/CommandController.php	validateCommand() now throws ApiProblemException::unprocessableEntity(...) instead of badRequest(...) when validation violations are detected.
Test Coverage tests/Unit/Exception/ApiProblemExceptionTest.php, tests/Unit/Controller/CommandControllerTest.php, tests/Functional/ScenarioTest.php	New unit tests for unprocessableEntity() verify violations storage and 422 status; CommandControllerTest refactored to use try/catch and assert HTTP_UNPROCESSABLE_ENTITY; functional tests updated to expect 422 in both creation and update validation error scenarios.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A hop, a skip, validation's trick,
Now errors land with status quite slick,
No longer four-oh-oh's gray haze,
Four-twenty-two blazes through the malformed maze, ✨
Proper codes make API dreams come true!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 16.67% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: mapping Symfony Validator constraint violations to HTTP 422 status code with RFC 7807 compliance. It aligns perfectly with the core modifications across all changed files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch unprocessable-entity

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