Handle thumb errors when !$enableLegacyMediaDOM

MediaTransformError implements MediaTransformOutput and so it has a
::toHtml to call but the output of that isn't phrasing content, as would
be required in the context in which parser output uses it when
!$enableLegacyMediaDOM.

Bug: T334659
Change-Id: I38618552c4916dc96eac2cb181d9fbbc418187b0

2 files changed, 28 insertions, 5 deletions

diff --git a/includes/gallery/TraditionalImageGallery.php b/includes/gallery/TraditionalImageGallery.php
index d9c39d2e4da4..5c37b13eaf35 100644
--- a/includes/gallery/TraditionalImageGallery.php
+++ b/includes/gallery/TraditionalImageGallery.php
@@ -6,6 +6,7 @@ use MediaWiki\Linker\LinkRenderer;
 use MediaWiki\MainConfigNames;
 use MediaWiki\MediaWikiServices;
 use MediaWiki\Title\Title;
+use Wikimedia\Assert\Assert;
 
 /**
  * Image gallery.
@@ -117,7 +118,7 @@ class TraditionalImageGallery extends ImageGalleryBase {
 			$isBadFile = $img && $thumb && $this->mHideBadImages &&
 				$badFileLookup->isBadFile( $nt->getDBkey(), $this->getContextTitle() );
 
-			if ( !$img || !$thumb || $isBadFile ) {
+			if ( !$img || !$thumb || ( !$enableLegacyMediaDOM && $thumb->isError() ) || $isBadFile ) {
 				$rdfaType = 'mw:Error ' . $rdfaType;
 
 				if ( $enableLegacyMediaDOM ) {
@@ -130,6 +131,12 @@ class TraditionalImageGallery extends ImageGalleryBase {
 					$currentExists = $img && $img->exists();
 					if ( $currentExists && !$thumb ) {
 						$label = wfMessage( 'thumbnail_error', '' )->text();
+					} elseif ( $thumb && $thumb->isError() ) {
+						Assert::invariant(
+							$thumb instanceof MediaTransformError,
+							'Unknown MediaTransformOutput: ' . get_class( $thumb )
+						);
+						$label = $thumb->toText();
 					} else {
 						$label = $alt ?? '';
 					}
diff --git a/includes/linker/Linker.php b/includes/linker/Linker.php
index ddebd1c2b988..d2310d525ddd 100644
--- a/includes/linker/Linker.php
+++ b/includes/linker/Linker.php
@@ -31,6 +31,7 @@ use Hooks;
 use HtmlArmor;
 use IContextSource;
 use Language;
+use MediaTransformError;
 use MediaTransformOutput;
 use MediaWiki\Html\Html;
 use MediaWiki\Html\HtmlHelper;
@@ -47,6 +48,7 @@ use SpecialPage;
 use TitleValue;
 use User;
 use WatchedItem;
+use Wikimedia\Assert\Assert;
 use Wikimedia\IPUtils;
 use Wikimedia\Parsoid\Core\TOCData;
 use Wikimedia\Rdbms\SelectQueryBuilder;
@@ -467,14 +469,20 @@ class Linker {
 			$thumb = false;
 		}
 
-		if ( !$thumb ) {
+		if ( !$thumb || ( !$enableLegacyMediaDOM && $thumb->isError() ) ) {
 			$rdfaType = 'mw:Error ' . $rdfaType;
 			$currentExists = $file && $file->exists();
 			if ( $enableLegacyMediaDOM ) {
 				$label = $frameParams['title'];
 			} else {
-				if ( $currentExists ) {
+				if ( $currentExists && !$thumb ) {
 					$label = wfMessage( 'thumbnail_error', '' )->text();
+				} elseif ( $thumb && $thumb->isError() ) {
+					Assert::invariant(
+						$thumb instanceof MediaTransformError,
+						'Unknown MediaTransformOutput: ' . get_class( $thumb )
+					);
+					$label = $thumb->toText();
 				} else {
 					$label = $frameParams['alt'] ?? '';
 				}
@@ -757,12 +765,20 @@ class Linker {
 				$title, $label, '', '', '', (bool)$time, $handlerParams, false
 			);
 			$zoomIcon = '';
-		} elseif ( !$thumb ) {
+		} elseif ( !$thumb || ( !$enableLegacyMediaDOM && $thumb->isError() ) ) {
 			$rdfaType = 'mw:Error ' . $rdfaType;
 			if ( $enableLegacyMediaDOM ) {
 				$s .= wfMessage( 'thumbnail_error', '' )->escaped();
 			} else {
-				$label = wfMessage( 'thumbnail_error', '' )->text();
+				if ( $thumb && $thumb->isError() ) {
+					Assert::invariant(
+						$thumb instanceof MediaTransformError,
+						'Unknown MediaTransformOutput: ' . get_class( $thumb )
+					);
+					$label = $thumb->toText();
+				} else {
+					$label = wfMessage( 'thumbnail_error', '' )->text();
+				}
 				$s .= self::makeBrokenImageLinkObj(
 					$title, $label, '', '', '', (bool)$time, $handlerParams, true
 				);