MySQL Bugs: #89113: Connector/Python cursors cannot act as a context manager

Bug #89113	Connector/Python cursors cannot act as a context manager
Submitted:	4 Jan 2018 23:12	Modified:	26 Jun 2020 21:52
Reporter:	Chris Foresman	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Connector / Python	Severity:	S4 (Feature request)
Version:	8.0.5b1, 8.0.12	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Most Python DB-API 2.0 compliant drivers can create cursors as a context manager, like so:

```python
with conn.cursor() as cur:
    cur.execute(query)
    result = cur.fetchone()
print(result)
```

The cursor is created and assigned the identifier `cur`, and when exiting the scope, the cursor is automatically closed.

How to repeat:
Assuming a function `database_connection` that successfully creates a connection using Connector/Python:

```python
>>> conn = database_connection()
>>> with conn.cursor() as cur:
...     cur.execute("""SELECT * FROM lab_order;""")
...     cur.fetchall()
... 
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: __enter__
```

Suggested fix:
Add `__enter__` and `__exit__` methods to the `Cursor` class to allow using it as a context manager.

You can see a bit how psycopg2 does it (it's written using Python's C API since it's a compiled module) but basically you just return the cursor object with the `__enter__` method, and call `self.close(); return None` in the `__exit__` method.

https://github.com/psycopg/psycopg2/blob/d2e86db8fb1fbf2f162d4e83dd66c96d48ac9a7d/psycopg/...

Hello Chris Foresman,

Thank you for the feature request!

regards,
Umesh

Posted by developer:
 
Fixed by WL#13847

Posted by developer:
 
Fixed as of the upcoming MySQL Connector/Python 8.0.21 release, and here's the proposed changelog entry from the documentation team:

Implemented context management support to help allocate resources as
needed.

Thank you for the bug report.

Note: this was fixed via WL #13847 ( via and MySQL bug #71663 )