Support extra header filters in JSON metadata parsing

Author: retlehs

src/wp-admin/includes/plugin.php

@@ -103,6 +103,11 @@ function _get_plugin_json_data( $plugin_file ) {
 		'updateUri'   => 'UpdateURI',
 	);
 
+	$extra_plugin_headers = (array) apply_filters( 'extra_plugin_headers', array() );
+	foreach ( $extra_plugin_headers as $extra_header ) {
+		$key_map[ $extra_header ] = $extra_header;
+	}
+
 	// Initialize all headers to empty strings (matching get_file_data() behavior).
 	$plugin_data = array(
 		'Name'            => '',
@@ -120,6 +125,9 @@ function _get_plugin_json_data( $plugin_file ) {
 		'RequiresPlugins' => '',
 		'_sitewide'       => '',
 	);
+	foreach ( $extra_plugin_headers as $extra_header ) {
+		$plugin_data[ $extra_header ] = '';
+	}
 
 	foreach ( $key_map as $json_key => $header_key ) {
 		if ( isset( $json_data[ $json_key ] ) ) {

src/wp-includes/class-wp-theme.php

@@ -898,11 +898,18 @@ private function read_json_metadata() {
 
 		$metadata = $theme_json_data['metadata'];
 
+		$extra_theme_headers = (array) apply_filters( 'extra_theme_headers', array() );
+
 		// Initialize all headers to empty strings (matching get_file_data() behavior).
-		$headers = array_fill_keys( array_keys( self::$file_headers ), '' );
+		$headers = array_fill_keys( array_merge( array_keys( self::$file_headers ), $extra_theme_headers ), '' );
+
+		$json_metadata_keys = self::$json_metadata_keys;
+		foreach ( $extra_theme_headers as $extra_header ) {
+			$json_metadata_keys[ $extra_header ] = $extra_header;
+		}
 
 		// Map JSON metadata keys to internal header keys.
-		foreach ( self::$json_metadata_keys as $json_key => $header_key ) {
+		foreach ( $json_metadata_keys as $json_key => $header_key ) {
 			if ( isset( $metadata[ $json_key ] ) ) {
 				if ( 'tags' === $json_key && is_array( $metadata[ $json_key ] ) ) {
 					$headers[ $header_key ] = implode( ', ', $metadata[ $json_key ] );

tests/phpunit/tests/admin/includesPluginJsonMetadata.php

@@ -12,6 +12,17 @@
  */
 class Tests_Admin_IncludesPluginJsonMetadata extends WP_UnitTestCase {
 
+	/**
+	 * Registers an extra plugin header for testing.
+	 *
+	 * @param string[] $headers Existing extra headers.
+	 * @return string[] Filtered extra headers.
+	 */
+	public function filter_extra_plugin_headers( $headers ) {
+		$headers[] = 'Custom Header';
+		return $headers;
+	}
+
 	/**
 	 * Tests that plugin.json metadata is read correctly.
 	 *
@@ -214,6 +225,48 @@ public function test_plugin_json_network_requires_strict_boolean_true() {
 		$this->assertSame( '', $int_one_data['Network'] );
 	}
 
+	/**
+	 * Tests that custom plugin headers registered via extra_plugin_headers are read from plugin.json.
+	 *
+	 * @ticket 24152
+	 */
+	public function test_plugin_json_supports_extra_plugin_headers() {
+		$plugin_dir  = WP_PLUGIN_DIR . '/json-custom-header-test-' . uniqid();
+		$dir_name    = basename( $plugin_dir );
+		$plugin_file = $plugin_dir . '/' . $dir_name . '.php';
+
+		add_filter( 'extra_plugin_headers', array( $this, 'filter_extra_plugin_headers' ) );
+		mkdir( $plugin_dir );
+		try {
+			file_put_contents(
+				$plugin_dir . '/plugin.json',
+				wp_json_encode(
+					array(
+						'name'          => 'Custom Header Plugin',
+						'version'       => '1.0.0',
+						'Custom Header' => 'Custom Header Value',
+					)
+				)
+			);
+			file_put_contents( $plugin_file, '<?php // test' );
+
+			$plugin_data = get_plugin_data( $plugin_file, false, false );
+			$this->assertSame( 'Custom Header Value', $plugin_data['Custom Header'] );
+		} finally {
+			remove_filter( 'extra_plugin_headers', array( $this, 'filter_extra_plugin_headers' ) );
+			if ( file_exists( $plugin_dir . '/plugin.json' ) ) {
+				unlink( $plugin_dir . '/plugin.json' );
+			}
+			if ( file_exists( $plugin_file ) ) {
+				unlink( $plugin_file );
+			}
+			if ( is_dir( $plugin_dir ) ) {
+				rmdir( $plugin_dir );
+			}
+			wp_clean_plugins_cache();
+		}
+	}
+
 	/**
 	 * Tests that plugin.json does not affect MU-plugins.
 	 *

tests/phpunit/tests/theme/wpThemeJsonMetadata.php

@@ -70,6 +70,17 @@ public function _theme_root( $dir ) {
 		return $this->theme_root;
 	}
 
+	/**
+	 * Registers an extra theme header for testing.
+	 *
+	 * @param string[] $headers Existing extra headers.
+	 * @return string[] Filtered extra headers.
+	 */
+	public function filter_extra_theme_headers( $headers ) {
+		$headers[] = 'Custom Header';
+		return $headers;
+	}
+
 	/**
 	 * Tests that theme.json metadata takes priority over style.css headers.
 	 *
@@ -152,6 +163,57 @@ public function test_block_theme_without_metadata_property_uses_stylesheet() {
 		$this->assertFalse( $theme->errors() );
 	}
 
+	/**
+	 * Tests that custom theme headers registered via extra_theme_headers are read from theme.json metadata.
+	 *
+	 * @ticket 24152
+	 */
+	public function test_theme_json_supports_extra_theme_headers() {
+		$theme_slug = 'json-custom-header-theme-' . wp_generate_password( 8, false );
+		$theme_dir  = $this->theme_root . '/' . $theme_slug;
+
+		add_filter( 'extra_theme_headers', array( $this, 'filter_extra_theme_headers' ) );
+		mkdir( $theme_dir );
+		try {
+			file_put_contents(
+				$theme_dir . '/theme.json',
+				wp_json_encode(
+					array(
+						'version'  => 3,
+						'metadata' => array(
+							'name'          => 'JSON Custom Header Theme',
+							'Custom Header' => 'Custom Theme Header Value',
+						),
+					)
+				)
+			);
+			file_put_contents( $theme_dir . '/style.css', "/*\nTheme Name: CSS Fallback\n*/\n" );
+			file_put_contents( $theme_dir . '/index.php', "<?php\n// Test theme.\n" );
+
+			wp_clean_themes_cache();
+			unset( $GLOBALS['wp_themes'] );
+
+			$theme = new WP_Theme( $theme_slug, $this->theme_root );
+			$this->assertSame( 'Custom Theme Header Value', $theme->get( 'Custom Header' ) );
+		} finally {
+			remove_filter( 'extra_theme_headers', array( $this, 'filter_extra_theme_headers' ) );
+			if ( file_exists( $theme_dir . '/theme.json' ) ) {
+				unlink( $theme_dir . '/theme.json' );
+			}
+			if ( file_exists( $theme_dir . '/style.css' ) ) {
+				unlink( $theme_dir . '/style.css' );
+			}
+			if ( file_exists( $theme_dir . '/index.php' ) ) {
+				unlink( $theme_dir . '/index.php' );
+			}
+			if ( is_dir( $theme_dir ) ) {
+				rmdir( $theme_dir );
+			}
+			wp_clean_themes_cache();
+			unset( $GLOBALS['wp_themes'] );
+		}
+	}
+
 	/**
 	 * Tests that active theme validation allows a JSON-metadata theme without style.css.
 	 *