regression: preserve gif animation and correct thumbnail after sharp bump

apps/meteor/server/lib/media/file-upload/lib/FileUpload.ts

@@ -40,6 +40,10 @@ import { validateAndDecodeJWT, generateJWT } from '../../../utils/lib/JWTHelper'
 import { fileUploadIsValidContentType } from '../../../utils/restrictions';
 
 const cookie = new Cookies();
+
+// Caps GIF frames decoded per thumbnail; limitInputPixels doesn't bound frame count.
+const MAX_ANIMATED_THUMBNAIL_PAGES = 100;
+
 let maxFileSize = 0;
 
 settings.watch('FileUpload_MaxFileSize', async (value: string) => {
@@ -328,15 +332,18 @@ export const FileUpload = {
 		const store = FileUpload.getStore('Uploads');
 		const image = await store._store.getReadStream(file._id, file);
 
-		let transformer = sharp().resize({ width, height, fit: 'inside' });
+		let transformer = (
+			file.type === 'image/gif' ? sharp({ pages: Math.min(file.identify?.pages ?? 1, MAX_ANIMATED_THUMBNAIL_PAGES) }) : sharp()
+		).resize({ width, height, fit: 'inside' });
 
 		if (file.type === 'image/svg+xml') {
 			transformer = transformer.png();
 		}
-		const result = transformer.toBuffer({ resolveWithObject: true }).then(({ data, info: { width, height, format } }) => ({
+		// pageHeight is the per-frame height; info.height is the full stacked height for animated input.
+		const result = transformer.toBuffer({ resolveWithObject: true }).then(({ data, info: { width, height, pageHeight, format } }) => ({
 			data,
 			width,
-			height,
+			height: pageHeight ?? height,
 			thumbFileType: (mime.lookup(format) as string) || '',
 			thumbFileName: file?.name as string,
 			originalFileId: file?._id as string,
@@ -391,6 +398,7 @@ export const FileUpload = {
 							height,
 						}
 					: undefined,
+			pages: metadata.pages,
 		};
 
 		const shouldRotate = settings.get<boolean>('FileUpload_RotateImages');
@@ -626,7 +634,9 @@ export const FileUpload = {
 			initialSize: file.size,
 		});
 
-		return new Promise((resolve, reject) => {
+		return new Promise<Buffer>((resolve, reject) => {
+			// Settle on write failure instead of hanging.
+			buffer.on('error', reject);
 			buffer.on('finish', () => {
 				const contents = buffer.getContents();
 				if (contents === false) {

packages/core-typings/src/IUpload.ts

@@ -23,6 +23,7 @@ export interface IUpload extends IRocketChatRecord {
 			width: number;
 			height: number;
 		};
+		pages?: number;
 	};
 	store?: string;
 	path?: string;