Update amp-toolbox-php to 0.6.0 (almost) and update error page to support fatal errors (in PHP 7+)

composer.json

@@ -14,7 +14,7 @@
     "ext-json": "*",
     "ext-libxml": "*",
     "ext-spl": "*",
-    "ampproject/amp-toolbox": "0.5.2",
+    "ampproject/amp-toolbox": "dev-main",
     "cweagans/composer-patches": "1.7.1",
     "fasterimage/fasterimage": "1.5.0",
     "sabberworm/php-css-parser": "dev-master#bfdd976"

includes/class-amp-theme-support.php

@@ -1666,34 +1666,10 @@ public static function finish_output_buffering( $response ) {
 
 		try {
 			$response = self::prepare_response( $response );
+		} catch ( Error $error ) { // Only PHP 7+.
+			$response = self::render_error_page( $error );
 		} catch ( Exception $exception ) {
-			$title   = __( 'Failed to prepare AMP page', 'amp' );
-			$message = __( 'A PHP error occurred while trying to prepare the AMP response. This may not be caused by the AMP plugin but by some other active plugin or the current theme. You will need to review the error details to determine the source of the error.', 'amp' );
-
-			$error_page = Services::get( 'dev_tools.error_page' );
-
-			$error_page
-				->with_title( $title )
-				->with_message( $message )
-				->with_exception( $exception )
-				->with_response_code( 500 );
-
-			// Add link to non-AMP version if not canonical.
-			if ( ! amp_is_canonical() ) {
-				$non_amp_url = amp_remove_paired_endpoint( amp_get_current_url() );
-
-				// Prevent user from being redirected back to AMP version.
-				if ( true === AMP_Options_Manager::get_option( Option::MOBILE_REDIRECT ) ) {
-					$non_amp_url = add_query_arg( QueryVar::NOAMP, QueryVar::NOAMP_MOBILE, $non_amp_url );
-				}
-
-				$error_page->with_back_link(
-					$non_amp_url,
-					__( 'Go to non-AMP version', 'amp' )
-				);
-			}
-
-			$response = $error_page->render();
+			$response = self::render_error_page( $exception );
 		}
 
 		/**
@@ -1708,6 +1684,41 @@ public static function finish_output_buffering( $response ) {
 		return $response;
 	}
 
+	/**
+	 * Render error page.
+	 *
+	 * @param Throwable $throwable Exception or (as of PHP7) Error.
+	 */
+	private static function render_error_page( $throwable ) {
+		$title   = __( 'Failed to prepare AMP page', 'amp' );
+		$message = __( 'A PHP error occurred while trying to prepare the AMP response. This may not be caused by the AMP plugin but by some other active plugin or the current theme. You will need to review the error details to determine the source of the error.', 'amp' );
+
+		$error_page = Services::get( 'dev_tools.error_page' );
+
+		$error_page
+			->with_title( $title )
+			->with_message( $message )
+			->with_throwable( $throwable )
+			->with_response_code( 500 );
+
+		// Add link to non-AMP version if not canonical.
+		if ( ! amp_is_canonical() ) {
+			$non_amp_url = amp_remove_paired_endpoint( amp_get_current_url() );
+
+			// Prevent user from being redirected back to AMP version.
+			if ( true === AMP_Options_Manager::get_option( Option::MOBILE_REDIRECT ) ) {
+				$non_amp_url = add_query_arg( QueryVar::NOAMP, QueryVar::NOAMP_MOBILE, $non_amp_url );
+			}
+
+			$error_page->with_back_link(
+				$non_amp_url,
+				__( 'Go to non-AMP version', 'amp' )
+			);
+		}
+
+		return $error_page->render();
+	}
+
 	/**
 	 * Filter rendered partial to convert to AMP.
 	 *

src/DevTools/ErrorPage.php

@@ -8,7 +8,10 @@
 namespace AmpProject\AmpWP\DevTools;
 
 use AmpProject\AmpWP\Infrastructure\Service;
+use Error;
 use Exception;
+use InvalidArgumentException;
+use Throwable;
 
 /**
  * Produces an error page similar to wp_die().
@@ -52,11 +55,11 @@ final class ErrorPage implements Service {
 	private $link_text = '';
 
 	/**
-	 * Exception of the error page.
+	 * Throwable of the error page.
 	 *
-	 * @var Exception
+	 * @var Throwable
 	 */
-	private $exception;
+	private $throwable;
 
 	/**
 	 * Response code of the error page.
@@ -118,13 +121,18 @@ public function with_back_link( $link_url, $link_text ) {
 	}
 
 	/**
-	 * Set the exception of the error page.
+	 * Set the throwable of the error page.
 	 *
-	 * @param Exception $exception Exception to use.
+	 * @param Throwable $throwable Exception or Error to use. The Throwable type does not exist in PHP 5,
+	 *                             which is why type is absent from the function parameter.
+	 * @throws InvalidArgumentException If $throwable is not an Exception or an Error.
 	 * @return self
 	 */
-	public function with_exception( Exception $exception ) {
-		$this->exception = $exception;
+	public function with_throwable( $throwable ) {
+		if ( ! ( $throwable instanceof Exception || $throwable instanceof Error ) ) {
+			throw new InvalidArgumentException( 'Parameter must be Throwable (Exception or Error).' );
+		}
+		$this->throwable = $throwable;
 		return $this;
 	}
 
@@ -163,7 +171,7 @@ public function render() {
 	}
 
 	/**
-	 * Send the exception that was caught to the error log.
+	 * Send the throwable that was caught to the error log.
 	 */
 	private function send_to_error_log() {
 		// Don't send to error log if fatal errors are not to be reported.
@@ -172,16 +180,18 @@ private function send_to_error_log() {
 			return;
 		}
 
-		error_log( // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
-			sprintf(
-				"%s - %s (%s) [%s]\n%s",
-				$this->message,
-				$this->exception->getMessage(),
-				$this->exception->getCode(),
-				get_class( $this->exception ),
-				$this->exception->getTraceAsString()
-			)
-		);
+		if ( null !== $this->throwable ) {
+			error_log( // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				sprintf(
+					"%s - %s (%s) [%s]\n%s",
+					$this->message,
+					$this->throwable->getMessage(),
+					$this->throwable->getCode(),
+					get_class( $this->throwable ),
+					$this->throwable->getTraceAsString()
+				)
+			);
+		}
 	}
 
 	/**
@@ -226,9 +236,10 @@ private function get_html( $styles, $text_direction ) {
 	</head>
 	<body id="error-page">
 		<h1>{$this->render_title()}</h1>
-		<p>{$this->render_message()}</p>
+		{$this->render_message()}
 		{$this->render_source()}
-		{$this->render_exception()}
+		{$this->render_support_link()}
+		{$this->render_throwable()}
 		{$this->render_back_link()}
 	</body>
 </html>
@@ -250,16 +261,42 @@ private function render_title() {
 	 * @return string KSES-sanitized message.
 	 */
 	private function render_message() {
-		return wp_kses_post( $this->message );
+		return '<p>' . wp_kses_post( $this->message ) . '</p>';
 	}
 
 	/**
-	 * Render the source of the exception file.
+	 * Render support link.
+	 *
+	 * @return string
+	 */
+	private function render_support_link() {
+		return '<p>' . wp_kses(
+			sprintf(
+				/* translators: %s is the AMP support forum URL. */
+				__( 'If you get stuck, you may want to share any details in a new topic on the plugin\'s <a href="%s" target="_blank" rel="noreferrer noopener">support forum</a>.', 'amp' ),
+				esc_url( __( 'https://wordpress.org/support/plugin/amp/', 'amp' ) )
+			),
+			[
+				'a' => [
+					'href'   => true,
+					'target' => true,
+					'rel'    => true,
+				],
+			]
+		) . '</p>';
+	}
+
+	/**
+	 * Render the source of the throwable.
 	 *
 	 * @return string File source data.
 	 */
 	private function render_source() {
-		$source = $this->likely_culprit_detector->analyze_exception( $this->exception );
+		if ( null === $this->throwable ) {
+			return '';
+		}
+
+		$source = $this->likely_culprit_detector->analyze_throwable( $this->throwable );
 
 		if ( ! empty( $source['type'] ) && ! empty( $source['name'] ) ) {
 			$name_markup = "<strong><code>{$source['name']}</code></strong>";
@@ -291,15 +328,14 @@ private function render_source() {
 	}
 
 	/**
-	 * Render the exception of the error page.
+	 * Render the throwable of the error page.
 	 *
-	 * The exception details are only rendered if both WP_DEBUG and
-	 * WP_DEBUG_DISPLAY are true.
+	 * The exception/error details are only rendered if both WP_DEBUG and WP_DEBUG_DISPLAY are true.
 	 *
-	 * @return string HTML describing the exception that was thrown.
+	 * @return string HTML describing the exception/error that was thrown.
 	 */
-	private function render_exception() {
-		if ( null === $this->exception ) {
+	private function render_throwable() {
+		if ( null === $this->throwable ) {
 			return '';
 		}
 
@@ -321,24 +357,24 @@ private function render_exception() {
 			[
 				sprintf(
 					'<strong>%s</strong> (%s) [<em>%s</em>]',
-					esc_html( $this->exception->getMessage() ),
-					esc_html( $this->exception->getCode() ),
-					esc_html( get_class( $this->exception ) )
+					esc_html( $this->throwable->getMessage() ),
+					esc_html( $this->throwable->getCode() ),
+					esc_html( get_class( $this->throwable ) )
 				),
 				sprintf(
 					'<em>%s:%d</em>',
-					esc_html( $this->exception->getFile() ),
-					esc_html( $this->exception->getLine() )
+					esc_html( $this->throwable->getFile() ),
+					esc_html( $this->throwable->getLine() )
 				),
 				'',
 				sprintf(
 					'<small>%s</small>',
-					esc_html( $this->exception->getTraceAsString() )
+					esc_html( $this->throwable->getTraceAsString() )
 				),
 			]
 		);
 
-		return "<hr><pre class='exception'>{$contents}</pre>";
+		return "<hr><pre class='throwable'>{$contents}</pre>";
 	}
 
 	/**
@@ -408,7 +444,7 @@ private function get_styles( $text_direction ) {
 		line-height: 1.5;
 		margin: 25px 0 20px;
 	}
-	#error-page .exception,
+	#error-page .throwable,
 	code {
 		font-family: Consolas, Monaco, monospace;
 		overflow-x: auto;