Test failures with PyPy3.11 7.3.20

[mgorny]

Describe the bug

When running the test suite, I'm seeing a few test failures that look like synchronization problems. My educated guess is that the code is relying on GC proactively removing/closing stuff, while PyPy's GC is far more conservative. Here's the output:

$ pytest
========================================================= test session starts =========================================================
platform linux -- Python 3.11.13[pypy-7.3.20-final], pytest-8.4.1, pluggy-1.6.0
rootdir: /tmp/mysqlclient
configfile: pyproject.toml
plugins: cov-6.2.1
collected 102 items                                                                                                                   

tests/test_MySQLdb_capabilities.py .........................                                                                    [ 24%]
tests/test_MySQLdb_dbapi20.py ...................................                                                               [ 58%]
tests/test_MySQLdb_nonstandard.py .................                                                                             [ 75%]
tests/test_MySQLdb_times.py ...........                                                                                         [ 86%]
tests/test__mysql.py .                                                                                                          [ 87%]
tests/test_connection.py ..                                                                                                     [ 89%]
tests/test_cursor.py ......FF.                                                                                                  [ 98%]
tests/test_errors.py ..                                                                                                         [100%]

============================================================== FAILURES ===============================================================
_________________________________________________ test_cursor_discard_result[Cursor] __________________________________________________

Cursor = <class 'MySQLdb.cursors.Cursor'>

    @pytest.mark.parametrize("Cursor", [MySQLdb.cursors.Cursor, MySQLdb.cursors.SSCursor])
    def test_cursor_discard_result(Cursor):
        conn = connect()
        cursor = conn.cursor(Cursor)
    
>       cursor.execute(
            """\
    CREATE TABLE test_cursor_discard_result (
        id INTEGER PRIMARY KEY AUTO_INCREMENT,
        data VARCHAR(100)
    )"""
        )

tests/test_cursor.py:197: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
src/MySQLdb/cursors.py:179: in execute
    res = self._query(mogrified_query)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
src/MySQLdb/cursors.py:330: in _query
    db.query(q)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <_mysql.connection open to 'localhost' at 0x55aeec242720>
query = b'CREATE TABLE test_cursor_discard_result (\n    id INTEGER PRIMARY KEY AUTO_INCREMENT,\n    data VARCHAR(100)\n)'

    def query(self, query):
        # Since _mysql releases GIL while querying, we need immutable buffer.
        if isinstance(query, bytearray):
            query = bytes(query)
>       _mysql.connection.query(self, query)
E       MySQLdb.OperationalError: (1050, "Table 'test_cursor_discard_result' already exists")

src/MySQLdb/connections.py:286: OperationalError
________________________________________________ test_cursor_discard_result[SSCursor] _________________________________________________

Cursor = <class 'MySQLdb.cursors.SSCursor'>

    @pytest.mark.parametrize("Cursor", [MySQLdb.cursors.Cursor, MySQLdb.cursors.SSCursor])
    def test_cursor_discard_result(Cursor):
        conn = connect()
        cursor = conn.cursor(Cursor)
    
>       cursor.execute(
            """\
    CREATE TABLE test_cursor_discard_result (
        id INTEGER PRIMARY KEY AUTO_INCREMENT,
        data VARCHAR(100)
    )"""
        )

tests/test_cursor.py:197: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
src/MySQLdb/cursors.py:179: in execute
    res = self._query(mogrified_query)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
src/MySQLdb/cursors.py:330: in _query
    db.query(q)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <_mysql.connection open to 'localhost' at 0x55aeec306710>
query = b'CREATE TABLE test_cursor_discard_result (\n    id INTEGER PRIMARY KEY AUTO_INCREMENT,\n    data VARCHAR(100)\n)'

    def query(self, query):
        # Since _mysql releases GIL while querying, we need immutable buffer.
        if isinstance(query, bytearray):
            query = bytes(query)
>       _mysql.connection.query(self, query)
E       MySQLdb.OperationalError: (1050, "Table 'test_cursor_discard_result' already exists")

src/MySQLdb/connections.py:286: OperationalError
======================================================= short test summary info =======================================================
FAILED tests/test_cursor.py::test_cursor_discard_result[Cursor] - MySQLdb.OperationalError: (1050, "Table 'test_cursor_discard_result' already exists")
FAILED tests/test_cursor.py::test_cursor_discard_result[SSCursor] - MySQLdb.OperationalError: (1050, "Table 'test_cursor_discard_result' already exists")
==================================================== 2 failed, 100 passed in 0.92s ====================================================

Environment

Gentoo Linux amd64
PyPy3.11 7.3.20
mariadbd Ver 11.8.2-MariaDB-log for Linux on x86_64 (Source distribution)

How did you install libmysqlclient libraries?

git repo

What version of mysqlclient do you use?

e54e861

Docker command to start MySQL server

mysql_install_db --no-defaults --auth-root-authentication-method=normal --basedir=/usr --datadir=/tmp/data
mysqld --no-defaults --character-set-server=utf8 --skip-networking --datadir=/tmp/data --socket=/tmp/sock

Minimum but complete code to reproduce

No response

Schema and initial data required to reproduce.

No response

Commands, and any other step required to reproduce your issue.

uv pip install -e . -r requirements.txt
pytest