[Fonts API] Relocate which fonts to print into wp_print_fonts()

lib/compat/wordpress-6.2/script-loader.php

@@ -129,28 +129,11 @@ function gutenberg_resolve_assets_override() {
 
 	$scripts = ob_get_clean();
 
-	/*
-	 * Generate font @font-face styles for the site editor iframe.
-	 * Use the registered font families for printing.
-	 */
-	if ( class_exists( 'WP_Fonts' ) ) {
-		$wp_fonts   = wp_fonts();
-		$registered = $wp_fonts->get_registered_font_families();
-		if ( ! empty( $registered ) ) {
-			$queue = $wp_fonts->queue;
-			$done  = $wp_fonts->done;
-
-			$wp_fonts->done  = array();
-			$wp_fonts->queue = $registered;
-
-			ob_start();
-			$wp_fonts->do_items();
-			$styles .= ob_get_clean();
-
-			// Reset the Web Fonts API.
-			$wp_fonts->done  = $done;
-			$wp_fonts->queue = $queue;
-		}
+	// Generate font @font-face styles.
+	if ( function_exists( 'wp_print_fonts' ) ) {
+		ob_start();
+		wp_print_fonts( true );
+		$styles .= ob_get_clean();
 	}
 
 	return array(

lib/compat/wordpress-6.3/script-loader.php

@@ -56,7 +56,7 @@ function _gutenberg_get_iframed_editor_assets() {
 
 	ob_start();
 	wp_print_styles();
-	wp_print_fonts();
+	wp_print_fonts( true );
 	$styles = ob_get_clean();
 
 	ob_start();

lib/experimental/fonts-api/fonts-api.php

@@ -176,9 +176,10 @@ function wp_register_font_provider( $name, $classname ) {
 	 *
 	 * @since X.X.X
 	 *
-	 * @param string|string[]|false $handles Optional. Items to be processed: queue (false),
-	 *                                       single item (string), or multiple items (array of strings).
-	 *                                       Default false.
+	 * @param string|string[]|bool $handles Optional. Items to be processed: queue (false),
+	 *                                      for iframed editor assets (true), single item (string),
+	 *                                      or multiple items (array of strings).
+	 *                                      Default false.
 	 * @return array|string[] Array of font handles that have been processed.
 	 *                        An empty array if none were processed.
 	 */
@@ -191,8 +192,15 @@ function wp_print_fonts( $handles = false ) {
 			return array();
 		}
 
-		if ( empty( $handles ) ) {
-			$handles = false;
+		// Skip this reassignment decision-making when using the default of `false`.
+		if ( false !== $handles ) {
+			// When `true`, print all registered fonts for the iframed editor.
+			if ( true === $handles ) {
+				$handles = $registered;
+			} elseif ( empty( $handles ) ) {
+				// When falsey, assign `false` to print enqueued fonts.
+				$handles = false;
+			}
 		}
 
 		_wp_scripts_maybe_doing_it_wrong( __FUNCTION__ );

phpunit/fonts-api/wpPrintFonts-test.php

@@ -123,4 +123,70 @@ private function setup_integrated_deps( array $setup, $wp_fonts, $enqueue = true
 			$wp_fonts->enqueue( $setup['enqueued'] );
 		}
 	}
+
+	/**
+	 * @dataProvider data_should_print_all_registered_fonts_for_iframed_editor
+	 *
+	 * @param string $fonts    Fonts to register.
+	 * @param array  $expected Expected results.
+	 */
+	public function test_should_print_all_registered_fonts_for_iframed_editor( $fonts, $expected ) {
+		wp_register_fonts( $fonts );
+
+		$this->expectOutputString( $expected['output'] );
+		$actual_done = wp_print_fonts( true );
+		$this->assertSameSets( $expected['done'], $actual_done, 'All registered font-family handles should be returned' );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array
+	 */
+	public function data_should_print_all_registered_fonts_for_iframed_editor() {
+		$local_fonts = $this->get_registered_local_fonts();
+		$font_faces  = $this->get_registered_fonts_css();
+
+		return array(
+			'Merriweather with 1 variation'      => array(
+				'fonts'    => array( 'merriweather' => $local_fonts['merriweather'] ),
+				'expected' => array(
+					'done'   => array( 'merriweather', 'merriweather-200-900-normal' ),
+					'output' => sprintf(
+						"<style id='wp-fonts-local' type='text/css'>\n%s\n</style>\n",
+						$font_faces['merriweather-200-900-normal']
+					),
+				),
+			),
+			'Source Serif Pro with 2 variations' => array(
+				'fonts'    => array( 'Source Serif Pro' => $local_fonts['Source Serif Pro'] ),
+				'expected' => array(
+					'done'   => array( 'source-serif-pro', 'Source Serif Pro-300-normal', 'Source Serif Pro-900-italic' ),
+					'output' => sprintf(
+						"<style id='wp-fonts-local' type='text/css'>\n%s%s\n</style>\n",
+						$font_faces['Source Serif Pro-300-normal'],
+						$font_faces['Source Serif Pro-900-italic']
+					),
+				),
+			),
+			'all fonts'                          => array(
+				'fonts'    => $local_fonts,
+				'expected' => array(
+					'done'   => array(
+						'merriweather',
+						'merriweather-200-900-normal',
+						'source-serif-pro',
+						'Source Serif Pro-300-normal',
+						'Source Serif Pro-900-italic',
+					),
+					'output' => sprintf(
+						"<style id='wp-fonts-local' type='text/css'>\n%s%s%s\n</style>\n",
+						$font_faces['merriweather-200-900-normal'],
+						$font_faces['Source Serif Pro-300-normal'],
+						$font_faces['Source Serif Pro-900-italic']
+					),
+				),
+			),
+		);
+	}
 }