MySQL Connector methods `fetchone` and `fetchmany` are not PEP 249 compliant

With Python 3.6.2 and MySQL Connector 2.1.6 package on Windows 10, not calling the execute method of a database cursor, or calling it on a non SELECT statement (CREATE, DROP, ALTER, INSERT, DELETE, UPDATE, etc.) yields the following results:

>>> import mysql.connector
>>> session = mysql.connector.connect(user = "root", database = "mysql")
>>> cursor = session.cursor()
>>> cursor.fetchone()
>>> cursor.fetchmany()
[]
>>> cursor.fetchall()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:UsersMaggyeroAppDataLocalProgramsPythonPython36-32libsite-packagesmysqlconnectorcursor.py", line 891, in fetchall
    raise errors.InterfaceError("No result set to fetch from.")
mysql.connector.errors.InterfaceError: No result set to fetch from.
>>> cursor.execute("CREATE TABLE test (x INTEGER)")
>>> cursor.fetchone()
>>> cursor.fetchmany()
[]
>>> cursor.fetchall()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:UsersMaggyeroAppDataLocalProgramsPythonPython36-32libsite-packagesmysqlconnectorcursor.py", line 891, in fetchall
    raise errors.InterfaceError("No result set to fetch from.")
mysql.connector.errors.InterfaceError: No result set to fetch from.

PEP 249 explicitly states for the fetchone, fetchmany and fetchall methods:

An Error (or subclass) exception is raised if the previous call to .execute*() did not produce any result set or no call was issued yet.

So why don’t fetchone and fetchmany raise an exception like fetchall?

Answer

I filed a bug report on bugs.mysql.com and the bug has been fixed in MySQL Connector/Python 8.0.23.

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Answer