Bug: DataclassSerializer cannot save datetime/UUID fields and does not rebuild nested dataclasses on replay

オープン
  • 何か問題がありますか？
#8,723 コメント 5 件 リアクション 0 件 担当者 1 名 GitHub で見る

メンテナーはふだん 1 日以内に返信

@Suraj1347 がすでに取り組んでいます。

2026年11月1日 から。

評価

難易度
3/5
見積もり時間
1〜2日
初心者へのやさしさ
75/100
issue の種類
バグ
明瞭さ
明確に書かれている
活発さ
活発
技術スタック
python
領域
backend

調査の方向性

Read AGENTS.md for test commands. Edit aws_lambda_powertools/utilities/idempotency/serialization/dataclass.py: make to_dict emit ISO strings and str for UUID, and have from_dict rebuild nested dataclasses via dataclasses.fields(). Add tests in tests/functional/idempotency/_boto3/test_idempotency.py verifying round-trip of UUID/datetime and nested dataclass equality. Done when replayed value equals original.

索引モデルが issue の本文から書いたものです。

説明

bug good first issue help wanted idempotency

[!WARNING]
For contributors, human or agent. Comment here to claim this issue and wait for the assignment before opening a PR; if two PRs show up, the assignee's stays. AI-assisted work is welcome, say so in the PR and tell us how you verified it: run the tests yourself and paste what you saw, do not describe runs you did not do. Read AGENTS.md first, it has the commands and the rules the CI enforces. This goes into 3.41.0.

Expected Behaviour

DataclassSerializer saves a dataclass result that contains datetime or UUID fields, and rebuilds nested dataclasses on replay, so the replayed value equals the original.

Current Behaviour

to_dict returns dataclasses.asdict(data) unchanged and save_success dumps it with the plain JSON encoder, which has no datetime/UUID support, so the first call fails with IdempotencyPersistenceLayerError (and then hits the stuck INPROGRESS record described in the companion issue for item 4). This is the same class of bug fixed for Pydantic in #8569. Separately, from_dict does self.__model(**data), so nested dataclasses come back as plain dicts on replay.

Code snippet
import uuid
from dataclasses import dataclass
from datetime import datetime
from aws_lambda_powertools.utilities.idempotency import idempotent_function
from aws_lambda_powertools.utilities.idempotency.serialization.dataclass import DataclassSerializer

@dataclass
class Item:
    sku: str

@dataclass
class Order:
    id: uuid.UUID
    created: datetime
    item: Item

@idempotent_function(data_keyword_argument="order", persistence_store=layer, output_serializer=DataclassSerializer)
def process(order: dict) -> Order:
    return Order(id=uuid.uuid4(), created=datetime(2026, 1, 1), item=Item(sku="x"))

process(order={"id": 1})  # IdempotencyPersistenceLayerError: Object of type UUID is not JSON serializable
# with only str fields: first call Order(item=Item(sku='x')), replay Order(item={'sku': 'x'})
Possible Solution

In aws_lambda_powertools/utilities/idempotency/serialization/dataclass.py: make to_dict produce JSON-safe values (ISO strings for datetime/date, str for UUID), and in from_dict rebuild nested dataclasses from dataclasses.fields() type hints (and lists of them). Tests in tests/functional/idempotency/_boto3/test_idempotency.py: a dataclass with UUID and datetime round-trips through save and replay, and a nested dataclass comes back as the dataclass, not a dict.

Item 6 of the Idempotency audit in #8603. No AWS resources needed.

Powertools for AWS Lambda (Python) version

latest

AWS Lambda function runtime

3.13

Packaging format used

PyPi

Debugging logs

No response

主要言語
Python
スター
3.3k
フォーク
511
平均マージ
3日 8時間
マージ済み PR（30日）
92

環境構築

はじめの一歩

  1. issue を最後まで読み、次にプロジェクトのコントリビューションガイドを読みます。
  2. 着手することを issue にコメントします — 二人が同じ作業をするのを防げます。
  3. リポジトリをフォークし、ブランチを切って変更します。
  4. issue 番号を参照したプルリクエストを送ります。

aws-powertools/powertools-lambda-python のほかの issue

aws-powertools/powertools-lambda-python の issue をすべて見る

似ている issue

Python の issue をもっと見る

新しい issue をメールで受け取る

初心者向けの GitHub issue を短くまとめたダイジェスト。