#20025 closed Bug (fixed)
Do something for MySQL under Python 3
Reported by: | Aymeric Augustin | Owned by: | Aymeric Augustin |
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Component: | Python 3 | Version: | dev |
Severity: | Release blocker | Keywords: | |
Cc: | Triage Stage: | Accepted | |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
If MySQLdb isn't ported to Python 3 by the time we release 1.6 alpha, we should either recommend an alternative if there's a solid one, or document that Django cannot be used with MySQL on Python 3.
Change History (18)
comment:1 by , 12 years ago
Description: | modified (diff) |
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comment:3 by , 12 years ago
Has patch: | set |
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Owner: | changed from | to
Status: | new → assigned |
Triage Stage: | Accepted → Ready for checkin |
Mailing-list thread: https://groups.google.com/d/msg/django-developers/8r_RVmUe5ys/WKWFy1owlyUJ
Pull request: https://github.com/django/django/pull/1044
I'll wait a few days for feedback.
comment:4 by , 12 years ago
Before merging this, we should install the library we recommend on ci.djangoproject.com and make sure the tests pass.
comment:5 by , 12 years ago
Patch needs improvement: | set |
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Triage Stage: | Ready for checkin → Accepted |
It turns out that the tests don't pass...
I made a few fixes and updated the pull request. The only remaining problem pertains to BinaryField
.
====================================================================== ERROR: test_set_and_retrieve (model_fields.tests.BinaryFieldTests) ---------------------------------------------------------------------- Traceback (most recent call last): File "/Users/myk/Documents/dev/django/tests/model_fields/tests.py", line 450, in test_set_and_retrieve self.assertEqual(bytes(dm.data), bytes(bdata)) TypeError: string argument without an encoding
(There's also three failures in the serializers_regress
tests but they have the same root cause.)
pdb
shows that dm.data
is "b'\\x00F\\xfe'"
instead of b'\x00F\xfe'
. In other words, str()
or force_str()
was incorrectly applied to the value.
comment:6 by , 12 years ago
This change helps a bit (thanks Claude for spotting the bug):
--- a/MySQLdb/__init__.py +++ b/MySQLdb/__init__.py @@ -73,7 +73,7 @@ def test_DBAPISet_set_inequality_membership(): assert FIELD_TYPE.DATE != STRING def Binary(x): - return str(x) + return bytes(x) def Connect(*args, **kwargs): """Factory function for connections.Connection."""
But then another exceptions occurs because MySQL-for-Python-3 assumes that all bytestrings can and should be utf-8 decoded (the point of the str
refactor in Python 3 is to forbid this):
====================================================================== ERROR: test_set_and_retrieve (model_fields.tests.BinaryFieldTests) ---------------------------------------------------------------------- Traceback (most recent call last): File "/Users/myk/Documents/dev/django/tests/model_fields/tests.py", line 448, in test_set_and_retrieve dm.save() File "/Users/myk/Documents/dev/django/django/db/models/base.py", line 548, in save force_update=force_update, update_fields=update_fields) File "/Users/myk/Documents/dev/django/django/db/models/base.py", line 576, in save_base updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields) File "/Users/myk/Documents/dev/django/django/db/models/base.py", line 663, in _save_table result = self._do_insert(cls._base_manager, using, fields, update_pk, raw) File "/Users/myk/Documents/dev/django/django/db/models/base.py", line 682, in _do_insert using=using, raw=raw) File "/Users/myk/Documents/dev/django/django/db/models/manager.py", line 226, in _insert return insert_query(self.model, objs, fields, **kwargs) File "/Users/myk/Documents/dev/django/django/db/models/query.py", line 1580, in insert_query return query.get_compiler(using=using).execute_sql(return_id) File "/Users/myk/Documents/dev/django/django/db/models/sql/compiler.py", line 884, in execute_sql cursor.execute(sql, params) File "/Users/myk/Documents/dev/django/django/db/utils.py", line 105, in inner return func(*args, **kwargs) File "/Users/myk/Documents/dev/django/django/db/backends/mysql/base.py", line 124, in execute return self.cursor.execute(query, args) File "/Users/myk/Documents/dev/MySQL-for-Python-3/mysql-py3/lib/python3.3/site-packages/MySQL_python-1.2.3-py3.3-macosx-10.8-x86_64.egg/MySQLdb/cursors.py", line 160, in execute query = query % db.literal(args) File "/Users/myk/Documents/dev/MySQL-for-Python-3/mysql-py3/lib/python3.3/site-packages/MySQL_python-1.2.3-py3.3-macosx-10.8-x86_64.egg/MySQLdb/connections.py", line 241, in literal return self.escape(o, self.encoders) File "/Users/myk/Documents/dev/MySQL-for-Python-3/mysql-py3/lib/python3.3/site-packages/MySQL_python-1.2.3-py3.3-macosx-10.8-x86_64.egg/MySQLdb/connections.py", line 190, in bytes_literal return db.literal(u.decode(bytes_literal.charset)) UnicodeDecodeError: 'utf-8' codec can't decode byte 0xfe in position 2: invalid start byte
I'm starting to doubt the quality of this port. Either no one's using MySQL on Python 3 besides toy projects, or I haven't found the library they're using :/
comment:7 by , 12 years ago
Patch needs improvement: | unset |
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I've updated the pull request with a commit that marks the affected tests as expected failures.
comment:8 by , 12 years ago
Resolution: | → fixed |
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Status: | assigned → closed |
comment:11 by , 12 years ago
Is there any chance of this getting into 1.5.2? I realize I can play with it on master (and I'll probably start there), but I will have an easier time experimenting with it at work if I can say I'm playing with an official release. More experimenting from me means the test coverage for Django (ok, so maybe not enough to be worth it, but it doesn't hurt to ask :).
comment:13 by , 11 years ago
I've backported the two commits that really matter.
Other commits are just ignoring tests that fail because of bugs in the MySQLdb port.
comment:15 by , 11 years ago
What about OurSQL? It has a PyPi package, and the django-connector is already written (also with a PyPi package)!
http://pythonhosted.org/oursql/
https://github.com/dcramer/django-oursql
I found it in a mailing thread where SQLAlchemy people were saying that the Oracle connector was causing a lot of issues, but OurSQL was the best one they'd found. @aaugustin Can you do a similar testing to OurSQL and django-oursql and see if it's running smoothly? I think it looks very promising, the django-connector even has some limited GIS support.
comment:16 by , 11 years ago
Sorry, I don't have any interest in this, besides making it possible to release Django 1.6.
comment:17 by , 11 years ago
Sorry if I'm being dumb, but this thread leaves me confused:
(*) There's a fork of MySQLdb that works with Python3 and Django 1.5.x? What's its URL?
() Does this fork of MySQLdb work with released Django 1.5.4? how about with released 1.5.1?
Thanks in advance.
At this time, the official MYSQLdb development has stalled.
There are several forks available on git-hub in order to port that library for Python 3:
At first sight, those ports seem to work with django-1.6 (master dev) -- with the minor modification of removing the use_unicode connection param. This modification was already available there: https://github.com/vsajip/django/blob/django3/django/db/backends/mysql/base.py#L386
however some sources state that there is a bunch of issues [...] in non-ascii environment:
http://python.6.n6.nabble.com/MySQL-Django-1-6-Python3-tt5009591.html#a5009904
As of myself, I've done some (very basic) preliminary tests using clelland/MySQL-for-Python-3 alone: Inserting and retrieving data containing non-ASCII characters (é, à, ç, è) appears to work. By examining the output of mysqldump, strings have been correctly encoded at DB level. I performed my tests against MySQL5.1 using both utf8 and latin1 as DB charset. Maybe there is some problems with the integration of both "Django 1.6" and "MySQL for Python 3"?
So, if someone could post here some data/link to the possible issues with MySQL-for-Python-3 & Django, that would help things in order not to drop MySQL support in Python 3 environment.