fix: resolve PHP 8.2 permission cache and font-dependent PHPUnit failures

inc/Core/FilesRepository/FilesystemHelper.php

@@ -106,6 +106,10 @@ public static function get(): ?\WP_Filesystem_Base {
 	 * @return bool True if the file is (or was made) group-writable, false otherwise.
 	 */
 	public static function make_group_writable( string $filepath, int $permissions = self::AGENT_FILE_PERMISSIONS ): bool {
+		// Atomic replacement or another process may have changed the inode or mode.
+		// Permission and ownership decisions must describe the current file.
+		clearstatcache( true, $filepath );
+
 		if ( ! file_exists( $filepath ) ) {
 			return false;
 		}
@@ -127,7 +131,10 @@ public static function make_group_writable( string $filepath, int $permissions =
 
 		// Suppress any residual warning — a failed chmod is non-fatal here.
 		// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_chmod, WordPress.PHP.NoSilencedErrors.Discouraged
-		return @chmod( $filepath, $permissions );
+		$result = @chmod( $filepath, $permissions );
+		// PHP 8.2 can retain the pre-chmod mode for subsequent stat calls.
+		clearstatcache( true, $filepath );
+		return $result;
 	}
 
 	/**

tests/Unit/Abilities/Media/StackTemplateTest.php

@@ -178,6 +178,11 @@ public function test_list_item_colors_render_without_leaking_to_other_items(): v
 			);
 			$paths = \DataMachine\Abilities\Media\BrandTokens::with_overrides( $data['brand'], static fn() => $t->render( $data, $r ) );
 			$this->files = array_merge( $this->files, $paths );
+			foreach ( array( 'body', 'heading' ) as $font ) {
+				if ( ! is_readable( $r->get_font( $font ) ) ) {
+					$this->markTestSkipped( 'Readable body and heading fonts required for pixel assertions.' );
+				}
+			}
 			$box = $t->plan_layout( $r, $data )[0];
 			$line = (int) ( 64 * 1.2 );
 			foreach ( array( 0 => 0xffffff, 1 => 0xff0000, 2 => 0xffffff ) as $i => $expected ) {

tests/filesystem-permission-cache-smoke.php

@@ -0,0 +1,48 @@
+<?php
+/**
+ * Permission helpers must expose current metadata, including on PHP 8.2.
+ *
+ * Run with: php tests/filesystem-permission-cache-smoke.php
+ *
+ * @package DataMachine\Tests
+ */
+
+require_once __DIR__ . '/bootstrap-unit.php';
+
+use DataMachine\Core\FilesRepository\FilesystemHelper;
+
+$permission_fixture = tempnam( sys_get_temp_dir(), 'datamachine-permissions-' );
+if ( false === $permission_fixture ) {
+	throw new RuntimeException( 'Could not create permission fixture.' );
+}
+
+try {
+	chmod( $permission_fixture, 0600 ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_chmod -- Tests native filesystem metadata.
+	clearstatcache( true, $permission_fixture );
+	if ( 0600 !== ( fileperms( $permission_fixture ) & 0777 ) ) {
+		throw new RuntimeException( 'Fixture must prime the restrictive mode in the stat cache.' );
+	}
+
+	if ( ! FilesystemHelper::make_group_writable( $permission_fixture ) ) {
+		throw new RuntimeException( 'Permission helper failed for an owned file.' );
+	}
+
+	// Do not clear the cache here: callers must immediately see the new mode.
+	if ( 0060 !== ( fileperms( $permission_fixture ) & 0060 ) ) {
+		throw new RuntimeException( 'Permission helper left stale metadata after chmod.' );
+	}
+
+	// Independent stat verifies the helper changed the file, not just its cache.
+	clearstatcache( true, $permission_fixture );
+	if ( 0060 !== ( fileperms( $permission_fixture ) & 0060 ) ) {
+		throw new RuntimeException( 'File on disk is not group-readable and writable.' );
+	}
+
+	if ( ! FilesystemHelper::make_group_writable( $permission_fixture ) ) {
+		throw new RuntimeException( 'Already shared file should remain successful.' );
+	}
+} finally {
+	unlink( $permission_fixture ); // phpcs:ignore WordPress.WP.AlternativeFunctions.unlink_unlink -- Removes native filesystem fixture.
+}
+
+echo "Filesystem permission cache smoke passed.\n";