概要
The request conflicts with the current state of the resource.
いつ発生するか
Returned for edit conflicts or when a create would violate a uniqueness constraint.
よくある原因
- Concurrent edit / lost-update conflict
- Duplicate value on a unique field
- Version mismatch on an update
解決方法
- Refetch the latest state and retry
- Resolve the conflicting change
- Use conditional requests with ETag / If-Match