.. include:: /Includes.rst.txt

.. _deprecation-99615-1674056024:

=================================================
Deprecation: #99615 - GeneralUtility::_GPmerged()
=================================================

See :issue:`99615`

Description
===========

The method :php:`\TYPO3\CMS\Core\Utility\GeneralUtility::_GPmerged()` has
been marked as deprecated and should not be used any longer.

Modern code should access `GET` and `POST` data from the PSR-7
:php:`\Psr\Http\Message\ServerRequestInterface`, and should avoid accessing
super-globals :php:`$_GET` and :php:`$_POST` directly. This helps creating
controller classes with a clean architecture. Some
:php:`\TYPO3\CMS\Core\Utility\GeneralUtility` related helper methods like
:php:`_GPmerged()` violate this, using them is considered a technical debt.
They are being phased out.


Impact
======

Calling the method will raise a deprecation level log error and will
stop working with TYPO3 v13.


Affected installations
======================

Instances with extensions using :php:`GeneralUtility::_GPmerged()` are affected.
The extension scanner will find usages with a strong match.


Migration
=========

:php:`GeneralUtility::_GPmerged()` is a helper method that retrieves
request parameters and returns the value, while `POST` parameters take
precedence over `GET` parameters, if both exist.

The same result can be achieved by retrieving arguments from the request object.
An instance of the PSR-7 :php:`ServerRequestInterface` is handed over to
controllers by TYPO3 Core's PSR-15 :php:`\TYPO3\CMS\Core\Http\RequestHandlerInterface`
and middleware implementations, and is available in various related scopes
like the frontend :php:`\TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer`.

Typical code:

..  code-block:: php

    use TYPO3\CMS\Core\Utility\GeneralUtility;
    use TYPO3\CMS\Core\Utility\ArrayUtility;

    // Before
    $getMergedWithPost = GeneralUtility::_GPmerged('tx_scheduler');

    // After
    $getMergedWithPost = $request->getQueryParams()['tx_scheduler'];
    ArrayUtility::mergeRecursiveWithOverrule($getMergedWithPost, $request->getParsedBody()['tx_scheduler']);

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