Build/Test Tools: Enable running the tests on PHP 8.4

PHP 8.4 is expected to be released at the end of November 2024.

Trac ticket 62061 contains a full analysis of the changes needed for WP to be ready for PHP 8.4 and all currently available patches for WP Core have been merged in the mean time.

Enabling the tests to run in CI on PHP 8.4 allows WordPress core to prevent new PHP 8.4 compatibility issues from being introduced.

Notes:
* While a [patch has been pulled](WordPress/wordpress-importer#172) for the Importer plugin, this patch has not been merged yet.
    This means there are currently still five failing tests. These failure are directly related to the Importer plugin and will be fixed once the PR for the plugin has been merged.
    To still allow WP Core to start structurally testing against PHP 8.4, these five tests have been set up now to be skipped on PHP 8.4.
    These tests skips should be removed again once the PR to the plugin has been merged.
* Xdebug-related tests will not be run on PHP 8.4 at this time as the Docker image for PHP 8.4 does not contain Xdebug yet. Once a stable release of Xdebug 3.4.0 is available, it can be added to the Docker image and the test step can then be enabled for PHP 8.4.

.github/workflows/phpunit-tests.yml

@@ -45,7 +45,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-latest ]
-        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3' ]
+        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.0', '8.1', '8.2', '8.3' ]
         tests-domain: [ 'example.org' ]
@@ -116,7 +116,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-latest ]
-        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3' ]
+        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
         db-type: [ 'mariadb' ]
         db-version: [ '10.4', '10.6', '10.11', '11.2' ]
         multisite: [ false, true ]

.github/workflows/reusable-phpunit-tests-v3.yml

@@ -182,7 +182,7 @@ jobs:
 
       # __fakegroup__ is excluded to force PHPUnit to ignore the <exclude> settings in phpunit.xml.dist.
       - name: Run (Xdebug) tests
-        if: ${{ inputs.php != '8.3' }}
+        if: ${{ inputs.php != '8.4' }}
         continue-on-error: ${{ inputs.allow-errors }}
         run: LOCAL_PHP_XDEBUG=true node ./tools/local-env/scripts/docker.js run php ./vendor/bin/phpunit -v --group xdebug --exclude-group __fakegroup__
 

.github/workflows/upgrade-testing.yml

@@ -43,7 +43,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-latest' ]
-        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3' ]
+        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.0' ]
         wp: [ '6.0', '6.1', '6.2', '6.3', '6.4', '6.5', '6.6' ]
@@ -93,7 +93,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-latest' ]
-        php: [ '8.0', '8.1', '8.2', '8.3' ]
+        php: [ '8.0', '8.1', '8.2', '8.3', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.0' ]
         wp: [ '5.3', '5.4', '5.5', '5.6', '5.7', '5.8', '5.9' ]
@@ -143,7 +143,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-latest' ]
-        php: [ '8.0', '8.1', '8.2', '8.3' ]
+        php: [ '8.0', '8.1', '8.2', '8.3', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.0' ]
         wp: [ '4.1', '4.2', '4.3', '4.4', '4.5' ]

.version-support-php.json

@@ -6,7 +6,8 @@
 		"8.0",
 		"8.1",
 		"8.2",
-		"8.3"
+		"8.3",
+		"8.4"
 	],
 	"6-6": [
 		"7.2",

tests/phpunit/tests/import/parser.php

@@ -25,6 +25,10 @@ public function set_up() {
 	 * @covers WXR_Parser_XML::parse
 	 */
 	public function test_malformed_wxr() {
+		if ( PHP_VERSION_ID >= 80400 ) {
+			$this->markTestSkipped( 'The Importer plugin is not ready for PHP 8.4 yet. This skip should be removed once it is.' );
+		}
+
 		$file = DIR_TESTDATA . '/export/malformed.xml';
 
 		// Regex based parser cannot detect malformed XML.
@@ -42,6 +46,10 @@ public function test_malformed_wxr() {
 	 * @covers WXR_Parser_Regex::parse
 	 */
 	public function test_invalid_wxr() {
+		if ( PHP_VERSION_ID >= 80400 ) {
+			$this->markTestSkipped( 'The Importer plugin is not ready for PHP 8.4 yet. This skip should be removed once it is.' );
+		}
+
 		$f1 = DIR_TESTDATA . '/export/missing-version-tag.xml';
 		$f2 = DIR_TESTDATA . '/export/invalid-version-tag.xml';
 
@@ -61,6 +69,10 @@ public function test_invalid_wxr() {
 	 * @covers WXR_Parser_Regex::parse
 	 */
 	public function test_wxr_version_1_1() {
+		if ( PHP_VERSION_ID >= 80400 ) {
+			$this->markTestSkipped( 'The Importer plugin is not ready for PHP 8.4 yet. This skip should be removed once it is.' );
+		}
+
 		$file = DIR_TESTDATA . '/export/valid-wxr-1.1.xml';
 
 		foreach ( array( 'WXR_Parser_SimpleXML', 'WXR_Parser_XML', 'WXR_Parser_Regex' ) as $p ) {
@@ -159,6 +171,10 @@ public function test_wxr_version_1_1() {
 	 * @covers WXR_Parser_Regex::parse
 	 */
 	public function test_wxr_version_1_0() {
+		if ( PHP_VERSION_ID >= 80400 ) {
+			$this->markTestSkipped( 'The Importer plugin is not ready for PHP 8.4 yet. This skip should be removed once it is.' );
+		}
+
 		$file = DIR_TESTDATA . '/export/valid-wxr-1.0.xml';
 
 		foreach ( array( 'WXR_Parser_SimpleXML', 'WXR_Parser_XML', 'WXR_Parser_Regex' ) as $p ) {
@@ -257,6 +273,10 @@ public function test_wxr_version_1_0() {
 	 * @covers WXR_Parser_Regex::parse
 	 */
 	public function test_escaped_cdata_closing_sequence() {
+		if ( PHP_VERSION_ID >= 80400 ) {
+			$this->markTestSkipped( 'The Importer plugin is not ready for PHP 8.4 yet. This skip should be removed once it is.' );
+		}
+
 		$file = DIR_TESTDATA . '/export/crazy-cdata-escaped.xml';
 
 		foreach ( array( 'WXR_Parser_SimpleXML', 'WXR_Parser_XML', 'WXR_Parser_Regex' ) as $p ) {