Magento 2.4 backward incompatible changes | Magento 2 Developer Documentation

This page highlights backward incompatible changes between releases that have a major impact and require detailed explanation and special instructions to ensure third-party modules continue working with Magento. High-level reference information for all backward incompatible changes in each release are documented in the Backward incompatible changes reference topic.

2.4.1 - 2.4.2

Compare lists

Magento uses session storage to work with compare lists. In version 2.4.2, Magento added GraphQL support for compare lists. Instead of relying on session storage, GraphQL now saves compare list information into the database, with each list assigned an ID. These changes are additive and do not alter the behavior of compare lists on the storefront. However, there is a chance these changes could affect third-party extensions that manage compare lists.

The following methods and property have been added to the Magento\Catalog\Model\ResourceModel\Product\Compare\Item\Collection class. They are available to all developers, not just those working on GraphQL.

getListId()
getProductsByListId()
removeCompareList()
setListId()
setListIdToCustomerCompareItems()
$listId

This feature introduces the following database changes:

Added the foreign key catalog_compare_item/CATALOG_COMPARE_ITEM_LIST_ID_CATALOG_COMPARE_LIST_LIST_ID
Added the catalog_compare_list table
Added the catalog_compare_item/list_id column

2.3.0 - 2.4

Elasticsearch

MySQL is no longer used for search. You must use Elasticsearch.

You must install and configure Elasticsearch 7.6.x before upgrading to Magento 2.4.0. New installations require a connection to Elasticsearch to complete.

Magento does not support Elasticsearch 2.x, 5.x, and 6.x. If you attempt to upgrade Magento before installing and configuring a supported search engine, Magento could go into an inconsistent state and the Admin will become inaccessible.

Extension developers must update any module that depends on the unsupported search engines.

The changes with removing values from the system.xml file require eliminating ES2 support from the Admin UI. Other API classes were removed to clean up the code when we deprecated ES2 and ES5 in Magento 2.3.5.

The following modules have been refactored to use the ElasticSearchResultApplier class and avoid usage of CatalogSearch and SearchResultApplier, which was based on MySQL:

CatalogGraphQL
QuickOrder (B2B)

In addition, the following constructors were modified to provide a mixed type. We have removed deprecated class private and protected components but have left their usages as arguments in the constructor for backward compatibility.

Magento\CatalogSearch\Model\ResourceModel\Fulltext\Collection
Magento\CatalogSearch\Model\ResourceModel\Advanced\Collection
Magento\CatalogSearch\Model\Indexer\Fulltext\Action\Full

We recommend that you do not inherit from any Magento class. If your extension does inherit from any of the classes above, make sure it is not using any of the deprecated or removed mixed type class members. For compatibility, modify your constructors accordingly.

The following deprecated interfaces were deleted. If your extension implements any of these interfaces, refactor your code to use the Elasticsearch module.

Magento\Framework\Search\Adapter\Mysql\Query\Builder\QueryInterface
Magento\CatalogSearch\Model\Search\FilterMapper\FilterStrategyInterface

The following deprecated classes were deleted. If your extension uses any of the above classes, then you must do a major refactor to your code to use the Elasticsearch module and not rely on the MySQL Search class implementations.

Magento\Framework\Search\Adapter\Mysql\DocumentFactory
Magento\Framework\Search\Adapter\Mysql\Mapper
Magento\Framework\Search\Adapter\Mysql\ScoreBuilder
Magento\Framework\Search\Adapter\Mysql\Query\Builder\Match
Magento\Framework\Search\Adapter\Mysql\Field\FieldFactory
Magento\Framework\Search\Adapter\Mysql\Aggregation\Builder
Magento\Framework\Search\Adapter\Mysql\Aggregation\DataProviderContainer
Magento\CatalogSearch\Model\Search\TableMapper
Magento\CatalogSearch\Model\Indexer\IndexerHandler
Magento\CatalogSearch\Model\Indexer\ProductFieldset
Magento\CatalogSearch\Model\Indexer\Scope\IndexTableNotExistException
Magento\CatalogSearch\Model\Indexer\Fulltext\Action\IndexIterator
Magento\CatalogSearch\Model\Adapter\Mysql\Filter\AliasResolver

Magento Functional Testing Framework (MFTF)

MFTF now uses Google Authenticator to execute tests with 2FA enabled. MFTF will not work with Magento 2.4.0 without additional configuration steps to enable Google Authenticator. See Configuring MFTF for Two-Factor Authentication (2FA).

Inventory asynchronous reindex

A new Stock/Source reindex strategy configuration setting option was added to the Admin to prevent index table collisions. The setting has the following options:

Synchronous
Asynchronous

Previously, it was possible to have a “burst” of activity that triggered contention of the index process. Even batching and deferring individual updates that were triggering the indexer, it was still highly likely that an index table collision would occur based on “other” activity.

For example, if the indexer was running based on schedule, and replenishment happens manually through the Admin or interaction with an order, indexing would be triggered. Previously, that would result in two processes attempting to index; one of those will “lose”, leading to a deadlocked/stale index.

changed.MAJOR: Magento\InventoryIndexer\Indexer\Stock\StockIndexer::__construct
/InventoryIndexer/Indexer/Stock/StockIndexer.php:28 M113 [public] Method parameter typing changed.
changed.MAJOR: Magento\InventoryIndexer\Indexer\SourceItem\SourceItemIndexer::__construct
/InventoryIndexer/Indexer/SourceItem/SourceItemIndexer.php:27 M113 [public] Method parameter typing changed.

JSON field support

MySQL 5.7 supports the native JSON data type: https://dev.mysql.com/doc/refman/5.7/en/json.html. Magento 2.4.0 now supports using JSON fields with a declarative schema.

Laminas

Migrating ZF2 components to Laminas introduced BICs in the following files:

Magento\Backend\App\Area\FrontNameResolver::_construct - _constructor argument type was changed
Magento\Framework\App\Response\HttpInterface::getHeader - declared return type was changed

Both files are API class/interface. These changes will be solved dynamically during runtime if you follow the recommended guidelines.

MediaContent and MediaContentApi modules

The ‘MediaContent’ and ‘MediaContentApi’ modules were introduced to provide the ability to manage relationships between content and media assets used in that content.

Additionally, observers have been added to the CMS and Catalog modules to save the relationship of corresponding entities to ‘MediaContent’ storage.

Method parameter typing changed

Method parameter typing was changed to leverage PHP 7+ Throwables and enable catching ALL possible errors that might expose confidential information, such as passwords.

Level Target/Location Code/Reason

Magento\Framework\App\Bootstrap::terminate
/lib/internal/Magento/Framework/App/Bootstrap.php:426 M114 [protected] Method parameter typing changed.

New bulk interfaces for inventory salability check

In order to support bulk check for products salability, we introduced two new interfaces:

Magento\InventorySalesApi\Api\AreProductsSalableInterface
Magento\InventorySalesApi\Api\AreProductsSalableForRequestedQtyInterface

These changes allow third-party developers to optimize performance by providing an implementation for bulk services.

Introduced a Bulk version of IsProductSalableForRequestedQtyInterface API
Introduced a Bulk version of IsProductSalableInterface when working with a list of items

PHP

PHP 7.4 support is added to Magento 2.4.0, and the lowest compatible version is PHP 7.3. As the result, some of the Composer libraries used by Magento have been updated.

This section lists the backward incompatible changes and deprecated features in PHP 7.4. During development, we also discovered changes in the behavior of the setcookie function:

setcookie("tst", "Test Message");
print_r(headers_list());
//PHP 7.3
Array
(
    [0] => X-Powered-By: PHP/7.3.14
    [1] => Set-Cookie: tst=Test+Message
)
//PHP 7.4
Array
(
    [0] => X-Powered-By: PHP/7.4.4
    [1] => Set-Cookie: tst=Test%20Message
)

PHPUnit

The current PHPUnit framework version used with Magento 2.4.0 is PHPUnit 9. This requires refactoring most PHPUnit-based tests.

The most critical changes include:

The methods listed below now have a void return type declaration:

PHPUnit\Framework\TestCase::setUpBeforeClass()
PHPUnit\Framework\TestCase::setUp()
PHPUnit\Framework\TestCase::assertPreConditions()
PHPUnit\Framework\TestCase::assertPostConditions()
PHPUnit\Framework\TestCase::tearDown()
PHPUnit\Framework\TestCase::tearDownAfterClass()
PHPUnit\Framework\TestCase::onNotSuccessfulTest()

The following methods have been removed, and you should change the implementation their tests:

assertAttributeContains()
assertAttributeNotContains()
assertAttributeContainsOnly()
assertAttributeNotContainsOnly()
assertAttributeCount()
assertAttributeNotCount()
assertAttributeEquals()
assertAttributeNotEquals()
assertAttributeEmpty()
assertAttributeNotEmpty()
assertAttributeGreaterThan()
assertAttributeGreaterThanOrEqual()
assertAttributeLessThan()
assertAttributeLessThanOrEqual()
assertAttributeSame()
assertAttributeNotSame()
assertAttributeInstanceOf()
assertAttributeNotInstanceOf()
assertAttributeInternalType()
assertAttributeNotInternalType()
attribute()
attributeEqualTo()
readAttribute()
getStaticAttribute()
getObjectAttribute()

The signature of assertContains(), assertNotContains(), assertEquals(), and assertNotEquals() were changed. In most cases, more specific methods should be used instead, like assertStringContainsString()

Tips and Tricks

Use \PHPUnit\Framework\Assert::assertEqualsCanonicalizing() if you need to compare two entities with a different order of elements. assertEquals() has been used before.
Use \PHPUnit\Framework\Assert::assertEqualsWithDelta() if you need non-strict comparison. assertEquals() with additional parameters has been used before.

Size field added to media_gallery_asset table

This is a dependency for the Adobe Stock integration.

A size field was added to the media_gallery_asset table to enable storing and using the media asset size. The Media Gallery Asset entity model and interface were updated accordingly.

The Magento\MediaGalleryApi\Api\Data\AssetInterface that was updated with a new public method in the scope of the changes is not marked as @api so it is not currently part of Magento API.

The possible impact is minimal: the table was introduced in 2.3.4 (just several month ago) and it was not used by any functionality in Magento 2 (only Adobe Stock Integration extension).

SVC failure due to adding strict types

This change fixes a bug where getDefaultLimitPerPageValue returns a value that is not available.

As a Store Administrator, you are able to provide the ‘Products per Page on Grid Allowed’ values and ‘Products per Page on Grid Default’ value. There is no verification, so you can accidentally set the default value to be one of the unavailable options.

The only stores that might be affected are the ones who changed the configuration value for ‘Default items per page’, without customizing possible options. Some system integrators customize either the default value or allowed values.

As a result, there is inconsistency between default and allowed values. So far this worked by coincidence, but after the change, that would be explicit.

Per technical guidelines, all new PHP files MUST have strict type mode enabled by starting with declare(strict_types=1);. All updated PHP files SHOULD have strict type mode enabled. PHP interfaces MAY have this declaration.

Strict typing was added to the app/code/Magento/Catalog/Helper/Product/ProductList.php file.

It caused SVC failures.

Return type now array (the same as before in DocBlock):

changed.MAJOR: Magento\Catalog\Helper\Product\ProductList::getAvailableLimit
/app/code/Magento/Catalog/Helper/Product/ProductList.php:122M120 [public] Method return typing

The input parameter is renamed to viewMode:

changed.MAJOR: Magento\Catalog\Helper\Product\ProductList::getAvailableLimit
/app/code/Magento/Catalog/Helper/Product/ProductList.php:122V060 [public] Method parameter name

Now returns int for DefaultLimitPerPageValue:

changed.MAJOR: Magento\Catalog\Helper\Product\ProductList::getDefaultLimitPerPageValue
/app/code/Magento/Catalog/Helper/Product/ProductList.php:147M120 [public] Method return typing changed.

UrlRewrite module

The Admin grid in the UrlRewrite module was moved to UI components and all unused blocks were removed. Added mass delete and inline edit actions.

adminhtml.block.url_rewrite.grid.container
adminhtml.block.url_rewrite.grid
adminhtml.url_rewrite.grid.columnSet
adminhtml.url_rewrite.grid.columnSet.url_rewrite_id
adminhtml.url_rewrite.grid.columnSet.store_id
adminhtml.url_rewrite.grid.columnSet.request_path
adminhtml.url_rewrite.grid.columnSet.target_path
adminhtml.url_rewrite.grid.columnSet.redirect_type
adminhtml.url_rewrite.grid.columnSet.actions

UUID validator

This code adds the Ramsey library as a UUID validator and creates wrappers for it. This feature is needed for the async-import project. They pass UUID to get status of the async-import, for that they need to validate UUID.