Harden pre-publish projection and client-metadata error handling

.github/changelog/fix-pre-publish-error-handling

@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+The Bluesky pre-publish preview now shows a clear message when it can't be generated — including a distinct one for permission errors — instead of failing without explanation.

build/pre-publish-panel/plugin.asset.php

@@ -1 +1 @@
-<?php return array('dependencies' => array('react-jsx-runtime', 'wp-api-fetch', 'wp-components', 'wp-core-data', 'wp-data', 'wp-editor', 'wp-element', 'wp-i18n', 'wp-plugins'), 'version' => '8fa0d7dd1bccedfa1d37');
+<?php return array('dependencies' => array('react-jsx-runtime', 'wp-api-fetch', 'wp-components', 'wp-core-data', 'wp-data', 'wp-editor', 'wp-element', 'wp-i18n', 'wp-plugins'), 'version' => '424b2fbff0951a70d6d3');

includes/rest/admin/class-pre-publish-controller.php

@@ -20,6 +20,7 @@
 use WP_REST_Request;
 use WP_REST_Response;
 use WP_REST_Server;
+use function Atmosphere\debug_log;
 use function Atmosphere\is_connected;
 use function Atmosphere\is_supported_post_type;
 
@@ -228,6 +229,27 @@ public function get_preview( WP_REST_Request $request ) {
 
 		try {
 			$projection = ( new Post( $draft ) )->project();
+		} catch ( \Throwable $e ) {
+			/*
+			 * `project()` runs the_content over raw, unsaved editor markup,
+			 * so a malformed block or a misbehaving content/shortcode filter
+			 * can throw. Return a structured error (and log the post ID for
+			 * support) instead of letting the keystroke-driven endpoint fatal
+			 * into an opaque 500.
+			 */
+			debug_log(
+				\sprintf(
+					'pre-publish projection failed for post %d: %s',
+					$draft->ID,
+					$e->getMessage()
+				)
+			);
+
+			return new \WP_Error(
+				'atmosphere_projection_failed',
+				\__( 'The Bluesky preview could not be generated.', 'atmosphere' ),
+				array( 'status' => 500 )
+			);
 		} finally {
 			\remove_filter( 'pre_http_request', $block_http, 0 );
 		}

includes/rest/class-client-metadata-controller.php

@@ -16,6 +16,7 @@
 use Atmosphere\OAuth\Client;
 use WP_REST_Response;
 use WP_REST_Server;
+use function Atmosphere\debug_log;
 use function Atmosphere\sanitize_text;
 
 /**
@@ -141,6 +142,15 @@ public function get_metadata(): WP_REST_Response {
 				\esc_html__( 'atmosphere_client_metadata must return an array with a non-empty string client_id and a redirect_uris list of admin URLs; falling back to the unfiltered metadata.', 'atmosphere' ),
 				'1.0.0'
 			);
+
+			/*
+			 * `_doing_it_wrong()` is silent in production. Also route the
+			 * failure through debug_log() so operators can opt into the
+			 * signal via the `atmosphere_debug_log` filter without enabling
+			 * WP_DEBUG site-wide — an OAuth client_id served from a
+			 * misbehaving filter is worth surfacing.
+			 */
+			debug_log( 'atmosphere_client_metadata filter returned an invalid value; using the unfiltered metadata.' );
 		}
 
 		$response = new WP_REST_Response( $metadata, 200 );

src/pre-publish-panel/plugin.js

@@ -45,7 +45,7 @@ function PrePublishPanel() {
 
 	const [ preview, setPreview ] = useState( null );
 	const [ loading, setLoading ] = useState( true );
-	const [ error, setError ] = useState( false );
+	const [ error, setError ] = useState( null );
 	const debounce = useRef( null );
 
 	useEffect( () => {
@@ -54,7 +54,7 @@ function PrePublishPanel() {
 		}
 
 		setLoading( true );
-		setError( false );
+		setError( null );
 
 		// Debounce so each keystroke doesn't fire a projector request.
 		clearTimeout( debounce.current );
@@ -76,8 +76,16 @@ function PrePublishPanel() {
 					setPreview( result );
 					setLoading( false );
 				} )
-				.catch( () => {
-					setError( true );
+				.catch( ( err ) => {
+					// Keep the error so the message can distinguish a
+					// permission failure from a transient one, and log it so
+					// a support report has something to go on.
+					// eslint-disable-next-line no-console -- Aid debugging.
+					console.error(
+						'ATmosphere pre-publish preview failed:',
+						err
+					);
+					setError( err );
 					setLoading( false );
 				} );
 		}, 400 );
@@ -89,7 +97,33 @@ function PrePublishPanel() {
 		return <Spinner />;
 	}
 
-	if ( error || ! preview ) {
+	if ( error ) {
+		const errorCode = error?.code;
+		const errorStatus = error?.data?.status;
+		// An expired/invalid nonce is a 403 too, but it's transient (a
+		// reload fixes it), so it must not read as a permission failure.
+		const isAuth =
+			'rest_cookie_invalid_nonce' !== errorCode &&
+			( 'rest_forbidden' === errorCode ||
+				401 === errorStatus ||
+				403 === errorStatus );
+
+		return (
+			<p>
+				{ isAuth
+					? __(
+							'You don’t have permission to preview this post.',
+							'atmosphere'
+					  )
+					: __(
+							'Could not load the Bluesky preview. Please try again.',
+							'atmosphere'
+					  ) }
+			</p>
+		);
+	}
+
+	if ( ! preview ) {
 		return (
 			<p>{ __( 'Could not load the Bluesky preview.', 'atmosphere' ) }</p>
 		);

tests/phpunit/tests/rest/admin/class-test-pre-publish-controller.php

@@ -116,6 +116,36 @@ public function test_preview_connected_short_form() {
 		$this->assertFalse( $data['records'][0]['over_limit'] );
 	}
 
+	/**
+	 * A projection that throws (e.g. malformed block markup tripping a
+	 * content filter) is caught and reported as a structured error, not an
+	 * opaque fatal.
+	 *
+	 * @covers ::get_preview
+	 */
+	public function test_preview_returns_error_when_projection_throws() {
+		$post = self::factory()->post->create_and_get( array( 'post_title' => '' ) );
+
+		$thrower = static function () {
+			throw new \RuntimeException( 'boom' );
+		};
+		\add_filter( 'the_content', $thrower, 9 );
+
+		try {
+			$result = $this->controller->get_preview(
+				$this->make_request( $post->ID, array( 'content' => 'A quick note.' ) )
+			);
+		} finally {
+			// Remove in finally so a failed assertion below can't leak the
+			// throwing filter into later tests.
+			\remove_filter( 'the_content', $thrower, 9 );
+		}
+
+		$this->assertInstanceOf( \WP_Error::class, $result );
+		$this->assertSame( 'atmosphere_projection_failed', $result->get_error_code() );
+		$this->assertSame( 500, $result->get_error_data()['status'] );
+	}
+
 	/**
 	 * A draft (not yet published) reports the real character count, not a
 	 * redacted zero. The transformer redacts non-published posts, so the