{
  "environment": "test",
  "trigger": {
    "entry": "/ai/canvas/:projectId",
    "file": "stage-20m.obj",
    "sourceUnit": "m",
    "lightweight": true,
    "quality": "performance",
    "storage": "local presigned upload with optional headers omitted"
  },
  "before": {
    "sourceUploadHTTP": 201,
    "headersPresent": false,
    "putAttempted": false,
    "completeAttempted": false,
    "exception": "TypeError: Cannot convert undefined or null to object",
    "uiMessage": "模型未能加载，当前场景保持不变。请检查文件后重试。",
    "screenshot": "import-failed.png"
  },
  "cause": {
    "frontend": "Object.entries(upload.headers)",
    "api": "ModelConversionService.prepareSource returned optional storage headers without normalizing its required browser response field",
    "storageContract": "OssService.getPreSignedUrlS3 headers is optional; local storage intentionally omits it"
  },
  "fix": {
    "backendSource": "be56a7e0ec79d1a1e7420d870709014ed4bf010a",
    "apiVersion": "3.23.0.20261003.1",
    "change": "Return upload.headers ?? {} in model-conversion source-upload API; leave supplied signature headers unchanged",
    "scope": "Model conversion upload plan only; generic storage behavior unchanged"
  },
  "regression": {
    "before": {
      "tests": 2,
      "failed": 1,
      "passed": 1,
      "seconds": 0.579,
      "failure": "browserPlan.upload.headers expected {} but received undefined"
    },
    "after": {
      "modelConversionTests": 13,
      "modelConversionSeconds": 0.84,
      "nxElapsedSeconds": 2.38,
      "storageTests": 27,
      "storageSeconds": 0.638,
      "storageNxElapsedSeconds": 1.87
    },
    "sharedBuildSeconds": 0.66,
    "apiNxBuildSeconds": 20.83
  }
}