Set tus properties more explicitly

packages/@uppy/aws-s3/src/index.ts

@@ -929,17 +929,14 @@ export default class AwsS3Multipart<
     // Since the Transloadit plugin uses the tus plugin underneath, it's possible to have file.tus
     // even though we are in this plugin.
     // @ts-expect-error typed in @uppy/tus
-    if (file.tus) {
-      // @ts-expect-error typed in @uppy/tus
-      Object.assign(opts, file.tus)
-    }
+    const tusOpts = file.tus
 
     return {
       ...file.remote?.body,
-      endpoint: opts.endpoint,
+      endpoint: tusOpts.endpoint ?? opts.endpoint,
       protocol: this.uppy.getState().remoteUploader || 's3-multipart',
       size: file.data.size,
-      headers: opts.headers,
+      headers: { ...opts.headers, ...tusOpts.headers },
       metadata: file.meta,
     }
   }

packages/@uppy/xhr-upload/src/index.ts

@@ -440,28 +440,25 @@ export default class XHRUpload<
       opts.allowedMetaFields,
       file.meta,
     )
-    // When you .use(AwsS3) with .use(Transloadit, { companionOnly: true }),
+    // When you .use(XHR) with .use(Transloadit, { companionOnly: true }),
     // local files are uploaded with this plugin and remote files with the Transloadit plugin.
     // Since the Transloadit plugin uses the tus plugin underneath, it's possible to have file.tus
     // even though we are in this plugin.
     // @ts-expect-error typed in @uppy/tus
-    if (file.tus) {
-      // @ts-expect-error typed in @uppy/tus
-      Object.assign(opts, file.tus)
-    }
+    const tusOpts = file.tus
 
     return {
       ...file.remote?.body,
       protocol: this.uppy.getState().remoteUploader || 'multipart',
-      endpoint: opts.endpoint,
+      endpoint: tusOpts.endpoint ?? opts.endpoint,
+      headers: { ...opts.headers, ...tusOpts.headers },
       size: file.data.size,
       fieldname: opts.fieldName,
       metadata: Object.fromEntries(
         allowedMetaFields.map((name) => [name, file.meta[name]]),
       ),
       httpMethod: opts.method,
       useFormData: opts.formData,
-      headers: opts.headers,
     }
   }