@uppy/tus: don't abort errored request (#6312)

this fixes #6287 , another similar attempted fix which didn't got merged
: #5683

in #5683 we discussed a more longer term solution but IMO that would be
a breaking change as it would change the event contract

AI Disclaimer : AI Used 

This fix is Manually Tested across **Chrome and Firefox**

packages/@uppy/tus/package.json

@@ -44,6 +44,7 @@
   "devDependencies": {
     "@uppy/core": "workspace:^",
     "jsdom": "^26.1.0",
+    "nock": "^13.1.0",
     "typescript": "^5.8.3",
     "vitest": "^3.2.4"
   },

packages/@uppy/tus/src/index.test.ts

@@ -1,5 +1,6 @@
-import Core from '@uppy/core'
-import { describe, expect, expectTypeOf, it } from 'vitest'
+import Core, { type UppyEventMap } from '@uppy/core'
+import nock from 'nock'
+import { afterEach, describe, expect, expectTypeOf, it } from 'vitest'
 import Tus, { type TusBody } from './index.js'
 
 describe('Tus', () => {
@@ -44,4 +45,61 @@ describe('Tus', () => {
       { xhr: XMLHttpRequest } | undefined
     >()
   })
+
+  describe('upload-error response', () => {
+    afterEach(() => {
+      nock.cleanAll()
+    })
+
+    it('sends the server response over the upload-error event', async () => {
+      nock('https://fake-endpoint.uppy.io')
+        .post('/files/')
+        .reply(
+          403,
+          JSON.stringify({
+            message:
+              'File cannot be uploaded as the BIN content type is disallowed!',
+            status_code: 403,
+          }),
+          { 'Content-Type': 'application/json' },
+        )
+
+      const core = new Core<any, TusBody>()
+      core.use(Tus, {
+        endpoint: 'https://fake-endpoint.uppy.io/files/',
+        // Avoid retrying so the failure surfaces immediately.
+        retryDelays: [],
+      })
+      const id = core.addFile({
+        type: 'application/octet-stream',
+        source: 'test',
+        name: 'test.bin',
+        data: new Blob([new Uint8Array(1024)]),
+      })
+
+      const event = new Promise<
+        Parameters<UppyEventMap<any, TusBody>['upload-error']>
+      >((resolve) => {
+        core.once('upload-error', (...args) => resolve(args))
+      })
+
+      await Promise.all([
+        core.upload().catch(() => {
+          // Core rejects the upload; we assert on the event/state instead.
+        }),
+        event.then(([, , response]) => {
+          expect(response?.status).toBe(403)
+          const { xhr } = response!.body!
+          expect(xhr).toBeInstanceOf(XMLHttpRequest)
+          expect(JSON.parse(xhr.responseText).message).toBe(
+            'File cannot be uploaded as the BIN content type is disallowed!',
+          )
+        }),
+      ])
+
+      // The response is also persisted on the file so it is available on the
+      // `complete` result and via `getFile`.
+      expect(core.getFile(id).response?.status).toBe(403)
+    })
+  })
 })

packages/@uppy/tus/src/index.ts

@@ -164,13 +164,28 @@ export default class Tus<M extends Meta, B extends Body> extends BasePlugin<
    * Clean up all references for a file's upload: the tus.Upload instance,
    * any events related to the file, and the Companion WebSocket connection.
    */
-  resetUploaderReferences(fileID: string, opts?: { abort: boolean }): void {
+  resetUploaderReferences(
+    fileID: string,
+    opts?: {
+      /** Terminate the upload on the server (sends a `DELETE` request). */
+      abort?: boolean
+      /**
+       * Abort the underlying request. Defaults to `true`. Set to `false` when
+       * the request has already completed (e.g. in the error handler), so the
+       * underlying `xhr` — and thus the server response — is preserved instead
+       * of being reset by `abort()`.
+       */
+      abortRequest?: boolean
+    },
+  ): void {
     const uploader = this.uploaders[fileID]
     if (uploader) {
-      uploader.abort()
+      if (opts?.abortRequest !== false) {
+        uploader.abort()
 
-      if (opts?.abort) {
-        uploader.abort(true)
+        if (opts?.abort) {
+          uploader.abort(true)
+        }
       }
 
       this.uploaders[fileID] = null
@@ -219,6 +234,12 @@ export default class Tus<M extends Meta, B extends Body> extends BasePlugin<
   ): Promise<tus.Upload | string> {
     this.resetUploaderReferences(file.id)
 
+    // Captured in `onError` and forwarded to the `upload-error` event in the
+    // `.catch` below, so consumers can read the failing server response.
+    let errorResponse:
+      | Omit<NonNullable<UppyFile<M, B>['response']>, 'uploadURL'>
+      | undefined
+
     // Create a new tus upload
     return new Promise<tus.Upload | string>((resolve, reject) => {
       let queuedRequest: ReturnType<RateLimitedQueue['run']>
@@ -291,6 +312,23 @@ export default class Tus<M extends Meta, B extends Body> extends BasePlugin<
       uploadOptions.onError = (err) => {
         this.uppy.log(err)
 
+        // tus-js-client only calls `onError` once it has given up retrying, so
+        // the request has already completed. Capture the server response (status
+        // + body) and forward it to the `upload-error` event and `file.response`,
+        // mirroring the shape emitted by `onSuccess`.
+        const originalResponse = (err as tus.DetailedError).originalResponse
+        if (originalResponse != null) {
+          errorResponse = {
+            status: originalResponse.getStatus(),
+            body: {
+              // We have to put `as XMLHttpRequest` because tus-js-client
+              // returns `any`, as the type differs in Node.js and the browser.
+              // In the browser it's always `XMLHttpRequest`.
+              xhr: originalResponse.getUnderlyingObject() as XMLHttpRequest,
+            } as unknown as B,
+          }
+        }
+
         const xhr =
           (err as tus.DetailedError).originalRequest != null
             ? (err as tus.DetailedError).originalRequest.getUnderlyingObject()
@@ -299,7 +337,11 @@ export default class Tus<M extends Meta, B extends Body> extends BasePlugin<
           err = new NetworkError(err, xhr)
         }
 
-        this.resetUploaderReferences(file.id)
+        // Do not abort the request here: it has already completed, and aborting
+        // it would reset the underlying `xhr` (status `0`, empty body) and
+        // discard the response we just captured. We still drop our references
+        // and remove the event listeners.
+        this.resetUploaderReferences(file.id, { abortRequest: false })
         queuedRequest?.abort()
 
         if (typeof opts.onError === 'function') {
@@ -516,7 +558,10 @@ export default class Tus<M extends Meta, B extends Body> extends BasePlugin<
         queuedRequest = this.requests.run(qRequest)
       })
     }).catch((err) => {
-      this.uppy.emit('upload-error', file, err)
+      // `errorResponse` is captured in the `onError` handler above (the request
+      // is intentionally not aborted there), so the server response is still
+      // available here to forward to the `upload-error` event.
+      this.uppy.emit('upload-error', file, err, errorResponse)
       throw err
     })
   }

packages/@uppy/tus/vitest.config.ts

@@ -0,0 +1,25 @@
+import { defineConfig } from 'vitest/config'
+
+// In the browser (where Uppy runs) tus-js-client uses its browser build, which
+// accepts `Blob`/`File` and `XMLHttpRequest`. Under the default Node resolution
+// Vitest would load the Node build, which only accepts `Buffer`/`Readable`.
+// Alias to the browser build so jsdom tests exercise the same code path as
+// production.
+export default defineConfig({
+  resolve: {
+    alias: {
+      'tus-js-client': 'tus-js-client/lib.esm/browser/index.js',
+    },
+  },
+  test: {
+    environment: 'jsdom',
+    // Run with the document origin set to the upload endpoint so requests in
+    // tests are same-origin. Otherwise jsdom treats them as cross-origin and
+    // hides the response status (`xhr.status === 0`).
+    environmentOptions: {
+      jsdom: {
+        url: 'https://fake-endpoint.uppy.io',
+      },
+    },
+  },
+})

yarn.lock

@@ -9089,6 +9089,7 @@ __metadata:
     "@uppy/core": "workspace:^"
     "@uppy/utils": "workspace:^"
     jsdom: "npm:^26.1.0"
+    nock: "npm:^13.1.0"
     tus-js-client: "npm:^4.2.3"
     typescript: "npm:^5.8.3"
     vitest: "npm:^3.2.4"