Fix MySQL issues during fixture loading

[jsdalton]

I just installed django-threadedcomments into a project I'm working on but had some issues when I ran tests. In a nutshell, fixtures were failing to load because of foreign key restraint failures, e.g.:

IntegrityError: (1452, 'Cannot add or update a child row: a foreign key constraint fails (`test_myproject`.`threadedcomments_comment`, CONSTRAINT `comment_ptr_id_refs_id_fa2e61cf` FOREIGN KEY (`comment_ptr_id`) REFERENCES `django_comments` (`id`))')

I guess it's possible these fixtures load correctly on other backends? (I imagine this might be why it hasn't been caught until now.) But I had to make two changes to get the fixtures to load properly and for the tests in HierarchyTest to work:

• Invert the order of the comments and threaded comments in simple_tree.json.
• Set all values of last_child in simple_tree.json to null, and then update the values in a setUp() method of HierarchyTest.

The common thread in the issues is that if you attempt to add a row with an ID that references a row that has not yet been created, it fails. These fixes resolve this and tests run.

Anyhow, I'm submitting the changes I needed to make to get tests to run as a pull request. Hopefully you'll find this of use. Thanks

[honzakral]

This is a bug of MySQL that it doesn't support deferred referential integrity checking. The proposed fix is a bit hackish - if fixtures don't work I would prefer you construct the entire comment tree manually via python. The current solution is a little bit of both which could potentially be very confusing.

Thanks

[jsdalton]

Yeah, I'll consider that when I re-visit and submit a new pull request if I come up with something cleaner.

The problem is really this one: https://code.djangoproject.com/ticket/3615 , which isn't specific to django-threadedcomments.

Jim Dalton
jim.dalton@furrybrains.com

On Jun 21, 2011, at 8:06 AM, HonzaKral wrote:

This is a bug of MySQL that it doesn't support deferred referential integrity checking. The proposed fix is a bit hackish - if fixtures don't work I would prefer you construct the entire comment tree manually via python. The current solution is a little bit of both which could potentially be very confusing.

Thanks

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#26 (comment)

[vdboor]

ok, can I close this ticket? It's open for a long time already.