Under Django 1.9, there are multiple failures in test_classify_failures.py, all with this exception: ValueError: <FailureMatch: FailureMatch object> FailureMatch instance isn't saved. Use bulk=False or save the object first. (see attachment for full output) This is due to: https://github.com/django/django/commit/adc0c4fbac98f9cb975e8fa8220323b2de638b46 Which is described in the release notes: https://docs.djangoproject.com/en/1.9/releases/1.9/#bulk-behavior-of-add-method-of-related-managers The updated docs now say: """ In the example above, in the case of a ForeignKey relationship, QuerySet.update() is used to perform the update. This requires the objects to already be saved. You can use the bulk=False argument to instead have the related manager perform the update by calling e.save(). """ (https://docs.djangoproject.com/en/1.9/ref/models/relations/#django.db.models.fields.related.RelatedManager.add) tl;dr we either need to use `bulk=False` (and switch back to the existing less performant behaviour), or else make sure we save the FailureMatch instance first, here: https://github.com/mozilla/treeherder/blob/729ca39908e031d67c97074b0637f1c42f60f9dc/treeherder/autoclassify/management/commands/autoclassify.py#L58 James, what would you prefer to do here?

(In reply to Ed Morley [:emorley] from comment #0) > James, what would you prefer to do here?

Let's save it first.

The code here has since been refactored and is no longer affected.