From 28712d8acfffa9cdabb88cb610bae14913fa185d Mon Sep 17 00:00:00 2001 From: Simon Charette Date: Fri, 15 Feb 2019 01:01:25 -0500 Subject: Refs #19544 -- Ignored auto-created through additions conflicts if supported. This prevents IntegrityError caused by race conditions between missing ids retrieval and bulk insertions. --- django/db/models/fields/related_descriptors.py | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'django') diff --git a/django/db/models/fields/related_descriptors.py b/django/db/models/fields/related_descriptors.py index 96b8a37583..52cb91d3a8 100644 --- a/django/db/models/fields/related_descriptors.py +++ b/django/db/models/fields/related_descriptors.py @@ -1110,14 +1110,20 @@ def create_forward_many_to_many_manager(superclass, rel, reverse): model=self.model, pk_set=missing_target_ids, using=db, ) - # Add the ones that aren't there already + # Add the ones that aren't there already. Conflicts can be + # ignored when the intermediary model is auto-created as + # the only possible collision is on the (sid_id, tid_id) + # tuple. The same assertion doesn't hold for user-defined + # intermediary models as they could have other fields + # causing conflicts which must be surfaced. + ignore_conflicts = self.through._meta.auto_created is not False self.through._default_manager.using(db).bulk_create([ self.through(**through_defaults, **{ '%s_id' % source_field_name: self.related_val[0], '%s_id' % target_field_name: target_id, }) for target_id in missing_target_ids - ]) + ], ignore_conflicts=ignore_conflicts) if self.reverse or source_field_name == self.source_field_name: # Don't send the signal when we are inserting the -- cgit v1.3