feat(client): Add support for interactive transactions (#613)

## Change Summary

closes #53

This PR also bumps the `typing-extensions` version for `NewType`
support.

TODO:
- [x] tests for behaviour wrt rollback
- [x] Check what `max_wait` does and document both options
- [x] Check if we need to bump the `typing-extensions` dep
- [x] Support for model based access
- [x] Fix synchronous tests
- [x] Docs (include timeout information) 

## Checklist

- [ ] Unit tests for the changes exist
- [ ] Tests pass without significant drop in coverage
- [ ] Documentation reflects changes where applicable
- [ ] Test snapshots have been
[updated](https://prisma-client-py.readthedocs.io/en/latest/contributing/contributing/#snapshot-tests)
if applicable

## Agreement

By submitting this pull request, I confirm that you can use, modify,
copy and redistribute this contribution, under the terms of your choice.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: RobertCraigie

.github/workflows/test.yml

@@ -112,7 +112,6 @@ jobs:
         run: |
           nox -s typesafety-mypy
 
-
   lint:
     name: lint
     runs-on: ubuntu-latest

Makefile

@@ -2,7 +2,7 @@
 bootstrap:
 	pip install -U wheel
 	pip install -U -e .
-	pip install -U -r pipelines/requirements/lint.txt
+	pip install -U -r pipelines/requirements/all.txt
 	python -m prisma_cleanup
 	prisma db push --schema=tests/data/schema.prisma
 	cp tests/data/dev.db dev.db

databases/constants.py

@@ -38,6 +38,7 @@ def _fromdir(path: str) -> list[str]:
         unsupported_features={
             'json_arrays',
             'array_push',
+            'transactions',
         },
     ),
     'sqlite': DatabaseConfig(
@@ -102,6 +103,7 @@ def _fromdir(path: str) -> list[str]:
     'arrays': [*_fromdir('arrays'), *_fromdir('types/raw_queries/arrays')],
     'array_push': _fromdir('arrays/push'),
     'json_arrays': ['arrays/test_json.py', 'arrays/push/test_json.py'],
+    'transactions': ['test_transactions.py'],
     # not yet implemented
     'date': [],
     'create_many': ['test_create_many.py'],

databases/requirements.txt

@@ -5,5 +5,6 @@ distro
 
 -r ../pipelines/requirements/deps/pyright.txt
 -r ../pipelines/requirements/deps/pytest.txt
+-r ../pipelines/requirements/deps/pytest-mock.txt
 -r ../pipelines/requirements/deps/pytest-asyncio.txt
 -r ../pipelines/requirements/deps/syrupy.txt

databases/sync_tests/test_transactions.py

@@ -0,0 +1,177 @@
+import time
+from typing import Optional
+
+import pytest
+
+import prisma
+from prisma import Prisma
+from prisma.models import User
+from ..utils import CURRENT_DATABASE
+
+
+def test_context_manager(client: Prisma) -> None:
+    """Basic usage within a context manager"""
+    with client.tx(timeout=10 * 100) as transaction:
+        user = transaction.user.create({'name': 'Robert'})
+        assert user.name == 'Robert'
+
+        # ensure not commited outside transaction
+        assert client.user.count() == 0
+
+        transaction.profile.create(
+            {
+                'description': 'Hello, there!',
+                'country': 'Scotland',
+                'user': {
+                    'connect': {
+                        'id': user.id,
+                    },
+                },
+            },
+        )
+
+    found = client.user.find_unique(
+        where={'id': user.id}, include={'profile': True}
+    )
+    assert found is not None
+    assert found.name == 'Robert'
+    assert found.profile is not None
+    assert found.profile.description == 'Hello, there!'
+
+
+def test_context_manager_auto_rollback(client: Prisma) -> None:
+    """An error being thrown when within a context manager causes the transaction to be rolled back"""
+    user: Optional[User] = None
+
+    with pytest.raises(RuntimeError) as exc:
+        with client.tx() as tx:
+            user = tx.user.create({'name': 'Tegan'})
+            raise RuntimeError('Error ocurred mid transaction.')
+
+    assert exc.match('Error ocurred mid transaction.')
+
+    assert user is not None
+    found = client.user.find_unique(where={'id': user.id})
+    assert found is None
+
+
+def test_batch_within_transaction(client: Prisma) -> None:
+    """Query batching can be used within transactions"""
+    with client.tx(timeout=10000) as transaction:
+        with transaction.batch_() as batcher:
+            batcher.user.create({'name': 'Tegan'})
+            batcher.user.create({'name': 'Robert'})
+
+        assert client.user.count() == 0
+        assert transaction.user.count() == 2
+
+    assert client.user.count() == 2
+
+
+def test_timeout(client: Prisma) -> None:
+    """A `TransactionExpiredError` is raised when the transaction times out."""
+    # this outer block is necessary becuse to the context manager it appears that no error
+    # ocurred so it will attempt to commit the transaction, triggering the expired error again
+    with pytest.raises(prisma.errors.TransactionExpiredError):
+        with client.tx(timeout=50) as transaction:
+            time.sleep(0.05)
+
+            with pytest.raises(prisma.errors.TransactionExpiredError) as exc:
+                transaction.user.create({'name': 'Robert'})
+
+            raise exc.value
+
+
+@pytest.mark.skipif(
+    CURRENT_DATABASE == 'sqlite', reason='This is currently broken...'
+)
+def test_concurrent_transactions(client: Prisma) -> None:
+    """Two separate transactions can be used independently of each other at the same time"""
+    timeout = 15000
+    with client.tx(timeout=timeout) as tx1, client.tx(timeout=timeout) as tx2:
+        user1 = tx1.user.create({'name': 'Tegan'})
+        user2 = tx2.user.create({'name': 'Robert'})
+
+        assert tx1.user.find_first(where={'name': 'Robert'}) is None
+        assert tx2.user.find_first(where={'name': 'Tegan'}) is None
+
+        found = tx1.user.find_first(where={'name': 'Tegan'})
+        assert found is not None
+        assert found.id == user1.id
+
+        found = tx2.user.find_first(where={'name': 'Robert'})
+        assert found is not None
+        assert found.id == user2.id
+
+        # ensure not leaked
+        assert client.user.count() == 0
+        assert (tx1.user.find_first(where={'name': user2.name})) is None
+        assert (tx2.user.find_first(where={'name': user1.name})) is None
+
+    assert client.user.count() == 2
+
+
+def test_transaction_raises_original_error(client: Prisma) -> None:
+    """If an error is raised during the execution of the transaction, it is raised"""
+    with pytest.raises(RuntimeError, match=r'Test error!'):
+        with client.tx():
+            raise RuntimeError('Test error!')
+
+
+def test_transaction_within_transaction_warning(client: Prisma) -> None:
+    """A warning is raised if a transaction is started from another transaction client"""
+    tx1 = client.tx().start()
+    with pytest.warns(UserWarning) as warnings:
+        tx1.tx().start()
+
+    assert len(warnings) == 1
+    record = warnings[0]
+    assert not isinstance(record.message, str)
+    assert (
+        record.message.args[0]
+        == 'The current client is already in a transaction. This can lead to surprising behaviour.'
+    )
+    assert record.filename == __file__
+
+
+def test_transaction_within_transaction_context_warning(
+    client: Prisma,
+) -> None:
+    """A warning is raised if a transaction is started from another transaction client"""
+    with client.tx() as tx1:
+        with pytest.warns(UserWarning) as warnings:
+            with tx1.tx():
+                pass
+
+    assert len(warnings) == 1
+    record = warnings[0]
+    assert not isinstance(record.message, str)
+    assert (
+        record.message.args[0]
+        == 'The current client is already in a transaction. This can lead to surprising behaviour.'
+    )
+    assert record.filename == __file__
+
+
+def test_transaction_not_started(client: Prisma) -> None:
+    """A `TransactionNotStartedError` is raised when attempting to call `commit()` or `rollback()`
+    on a transaction that hasn't been started yet.
+    """
+    tx = client.tx()
+
+    with pytest.raises(prisma.errors.TransactionNotStartedError):
+        tx.commit()
+
+    with pytest.raises(prisma.errors.TransactionNotStartedError):
+        tx.rollback()
+
+
+def test_transaction_already_closed(client: Prisma) -> None:
+    """Attempting to use a transaction outside of the context block raises an error"""
+    with client.tx() as transaction:
+        pass
+
+    with pytest.raises(prisma.errors.TransactionExpiredError) as exc:
+        transaction.user.delete_many()
+
+    assert exc.match('Transaction already closed')