mpeteuil opened a new pull request, #37465: URL: https://github.com/apache/airflow/pull/37465
Currently DAGs accept a [`Collection["Dataset"]`](https://github.com/apache/airflow/blob/0c02ead4d8a527cbf0a916b6344f255c520e637f/airflow/models/dag.py#L171) as an option for the `schedule`, but that collection cannot be a `set` because Datasets are not a hashable type. The interesting thing is that [the `DatasetModel` is actually already hashable](https://github.com/apache/airflow/blob/dec78ab3f140f35e507de825327652ec24d03522/airflow/models/dataset.py#L93-L100), so this introduces a bit of duplication since it's mostly the same implementation. However, Airflow users are primarily interfacing with `Dataset`, not `DatasetModel` so I think it makes sense for `Dataset` to be hashable. I'm not sure how to square the duplication or what `__eq__` and `__hash__` provide for `DatasetModel` though. There was discussion [on the original PR that created the `DatasetModel`](https://github.com/apache/airflow/pull/24613) about whether to create two classes or one. In that discussion @kaxil mentioned: > I would slightly favour a separate `DatasetModel` and `Dataset` so `Dataset` becomes an extensible class, and `DatasetModel` just stores the info about the class. So users don't need to care about SQLAlchmey stuff when extending it. That provides a bit of background on why they both exist for anyone reading this who is curious. <!-- Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> <!-- Thank you for contributing! Please make sure that your code changes are covered with tests. And in case of new features or big changes remember to adjust the documentation. Feel free to ping committers for the review! In case of an existing issue, reference it using one of the following: closes: #ISSUE related: #ISSUE How to write a good git commit message: http://chris.beams.io/posts/git-commit/ --> <!-- Please keep an empty line above the dashes. --> --- **^ Add meaningful description above** Read the **[Pull Request Guidelines](https://github.com/apache/airflow/blob/main/contributing-docs/05_pull_requests.rst#pull-request-guidelines)** for more information. In case of fundamental code changes, an Airflow Improvement Proposal ([AIP](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+Improvement+Proposals)) is needed. In case of a new dependency, check compliance with the [ASF 3rd Party License Policy](https://www.apache.org/legal/resolved.html#category-x). In case of backwards incompatible changes please leave a note in a newsfragment file, named `{pr_number}.significant.rst` or `{issue_number}.significant.rst`, in [newsfragments](https://github.com/apache/airflow/tree/main/newsfragments). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@airflow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org