Transactions - Bug when using transaction APIs explicitly (not through the context manager)

[flea89]

TL;DR : when using trx.begin() and trx.commit() the transactions don't behave as expected.

Please refer to this merge request to see the bug highlighted in the test.

From a quick look at the code, the problem seems to be the transaction is not added to the client._batch_stack when the APIs are called explicitly.
_push_batch an _pop_batch are called only through the context manager __enter__ and __exit__.

Because of this
client.current_batch and current_transaction

Environment details

• OS type and version: MacOs Ventura 13.1
• Python version: 3.8.16
• pip version: 22.0.4
• google-cloud-datastore version: 2.15.2

Steps to reproduce

1. Create a transaction client.transaction()
2. Start a transaction txn.begin()
3. Get an object entity_in_txn = client.get(key)
4. Update and put the same entity outside of the transaction.
5. Update the entity and put the entity within the transaction
6. Commit the transaction txn.commit()

The transaction should raise a Conflit but it doesn't.
(When doing the same with the context manager the Exeption is raised, see here

Code example

See here

Stack trace

# example
N/A