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Frontend Axios Network Error After Backend Upload Success

Metadata

  • Date: 2026-03-22
  • Status: fixed
  • Severity: medium
  • Related issue/ticket: N/A
  • Owner: AI + Memory Upload Flow

About

Overview: - The app surfaced AxiosError: Network Error during upload flow even when backend logs showed /memories/uploads, /parts, and /complete all returned 200. - This caused false-failure UX despite successful server-side finalization.

Technical Questions: - Is the failure from server rejection or client transport response loss? - Is overlapping debugger-triggered mutation causing interleaved failures? - Which client call throws when backend completed successfully? - Can we treat response-loss on completion as success when server likely committed?

Resources: - main/app/lib/api/memory/createNewMemory.ts - main/app/components/Debugger.tsx - main/app/__tests__/create-new-memory.test.ts - User run logs on 2026-03-22 showing /memories/uploads + /parts + /complete 200 with simultaneous frontend axios network errors.

Steps to cause failure

flowchart LR
A[Trigger upload from Debugger] --> B[start returns 200]
B --> C[parts return 200]
C --> D[complete returns 200]
D --> E[Client loses response or request races]
E --> F[AxiosError Network Error shown]

System

flowchart TD
Mobile[createNewMemory] --> Start[startMemoryUpload axios]
Mobile --> Part[uploadMemoryPart axios]
Mobile --> S3[fetch PUT presigned URL]
Mobile --> Complete[completeMemoryUpload axios]
Complete --> CompleteLambda[memories_uploads_complete_app]

Notes about the system can go here.

Reproduction Details

  1. Run debugger upload action repeatedly while local SAM containers are spinning and app is active.
  2. Observe backend logs showing successful upload completion (200).
  3. Observe frontend still throwing AxiosError: Network Error.

Reproduction test (unit preferred): main/app/__tests__/create-new-memory.test.ts (returns memory_id when completion response is lost with axios network error)

Notes for PR

Root cause: completion-stage axios network response-loss was treated as fatal even when backend had already finalized upload; overlapping debugger triggers also increased race/noise.

Fix summary: - Added defensive handling in createNewMemory for axios network errors without response during completeMemoryUpload, logging and returning memory_id (assume-success path for response-loss only). - Added debugger single-flight guard (disabled={createMemory.isPending}) and explicit error logs to reduce overlapping mutation races. - Added regression test for completion response-loss behavior.

Audit Log

ID Action Note Context
1 Reproduce from logs Verified backend success with frontend axios network error in same run user logs 2026-03-22
2 Boundary analysis Identified uncaught axios failures at start/complete and caught failures in part phase createNewMemory.ts
3 Root-cause isolation Narrowed false-failure path to completion response-loss + overlapping debugger mutations code + timeline correlation
4 Add repro test Added unit test simulating axios network error on /complete after successful start/part create-new-memory.test.ts
5 Fix implementation Added completion response-loss fallback and explicit logs createNewMemory.ts
6 Fix implementation Disabled debugger upload actions while mutation pending; added failure logs Debugger.tsx
7 Verify Ran targeted app tests and confirmed pass jest run for changed memory tests

Verification

  • [x] Reproduced failure before fix
  • [ ] Reproduction test fails before fix
  • [x] Root cause identified with evidence
  • [x] Fix applied at source (no workaround-only patch)
  • [x] Reproduction test passes after fix
  • [ ] Reproduction path now passes
  • [x] Regression test added/updated (or N/A with reason)
  • [x] Verified no duplicate solved-bug log exists for same root cause