Bug #71124 callproc function with bytes parameters
Submitted: 10 Dec 2013 15:18 Modified: 12 Mar 2014 1:33
Reporter: Bulat Gaifullin Email Updates:
Status: Closed Impact on me:
Category:Connector / Python Severity:S1 (Critical)
Version:1.0.12-1 OS:Linux (Fedora19)
Assigned to: CPU Architecture:Any
Tags: bytes, connector, python

[10 Dec 2013 15:18] Bulat Gaifullin
If stored procedure has VARBINARY(BINARY) input argument callproc method raises exception.

Traceback (most recent call last):
  File "/usr/lib/python3.3/site-packages/mysql/connector/conversion.py", line 260, in to_python
    return getattr(self, func_name)(value, flddsc)
  File "/usr/lib/python3.3/site-packages/mysql/connector/conversion.py", line 421, in _BLOB_to_python
    return self._STRING_to_python(v, dsc)
  File "/usr/lib/python3.3/site-packages/mysql/connector/conversion.py", line 411, in _STRING_to_python
    return v.decode(self.charset)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xfb in position 0: invalid start byte

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.3/site-packages/mysql/connector/cursor.py", line 297, in _row_to_python
    res += (self._connection.converter.to_python(flddsc, v),)
  File "/usr/lib/python3.3/site-packages/mysql/connector/conversion.py", line 265, in to_python
    raise ValueError("%s (field %s)" % (e, flddsc[0]))
ValueError: 'utf-8' codec can't decode byte 0xfb in position 0: invalid start byte (field @_create_datacenter_arg3)

How to repeat:
CREATE PROCEDURE `proce_with_binary` (data VARBINARY(512))

cursor = mysql.connector.connect(test_database).cursor()
cursor.callproc('proce_with_binary', (b"\xfb"))
[17 Dec 2013 12:16] Geert Vanderkelen
Posted by developer:
Problem: executing call procedures and getting the result is done by using session variables. These session variables are typeless. Thus, a VARBINARY, we can not handle it correctly and check if it is 'binary' or not.
[17 Dec 2013 12:23] Geert Vanderkelen
Posted by developer:
A not-so-good workaround, but might help when really needed, is to use "use_unicode=False" for connection dealing with VARBINARY and calling stored procedures.
[17 Dec 2013 17:23] Bulat Gaifullin
It is possible to extract types of variables that will be passed to callproc method and use this knowledge to convert SQL-result back to python variables properly in fetchone method.
[24 Feb 2014 13:00] Bulat Gaifullin
any updates?
[12 Mar 2014 1:33] Paul Dubois
Noted in 1.2.1 changelog.

Connector/Python now permits the type for stored procedure parameters
to be specified. To do this, specify a parameter as a two-item tuple
consisting of the parameter value and type. For more information, see