Drop FK constraint on media_obj in MediaDecisionThrough, update backf…

…illmoderationdecision command (#4530)

* Remove foreign key constraint on media_obj from decision through table

* Create MediaDecisionThrough objects using identifier rather than instance

* On delete DO_NOTHING

api/api/management/commands/backfillmoderationdecision.py

@@ -94,7 +94,9 @@ def handle(self, *args, **options):
             MediaReport.objects.bulk_update(reports_chunk, ["decision"])
             MediaDecisionThrough.objects.bulk_create(
                 [
-                    MediaDecisionThrough(media_obj=report.media_obj, decision=decision)
+                    MediaDecisionThrough(
+                        media_obj_id=report.media_obj_id, decision=decision
+                    )
                     for report, decision in zip(reports_chunk, decisions)
                 ]
             )

api/api/migrations/0067_alter_audiodecisionthrough_media_obj_and_more.py

@@ -0,0 +1,24 @@
+# Generated by Django 4.2.11 on 2024-06-24 17:47
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('api', '0066_rename_contentprovider_to_contentsource'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='audiodecisionthrough',
+            name='media_obj',
+            field=models.ForeignKey(db_column='identifier', db_constraint=False, on_delete=django.db.models.deletion.DO_NOTHING, to='api.audio', to_field='identifier'),
+        ),
+        migrations.AlterField(
+            model_name='imagedecisionthrough',
+            name='media_obj',
+            field=models.ForeignKey(db_column='identifier', db_constraint=False, on_delete=django.db.models.deletion.DO_NOTHING, to='api.image', to_field='identifier'),
+        ),
+    ]

api/api/models/audio.py

@@ -366,8 +366,9 @@ class AudioDecisionThrough(AbstractMediaDecisionThrough):
     media_obj = models.ForeignKey(
         Audio,
         to_field="identifier",
-        on_delete=models.CASCADE,
+        on_delete=models.DO_NOTHING,
         db_column="identifier",
+        db_constraint=False,
     )
     decision = models.ForeignKey(AudioDecision, on_delete=models.CASCADE)
 

api/api/models/image.py

@@ -169,8 +169,9 @@ class ImageDecisionThrough(AbstractMediaDecisionThrough):
     media_obj = models.ForeignKey(
         Image,
         to_field="identifier",
-        on_delete=models.CASCADE,
+        on_delete=models.DO_NOTHING,
         db_column="identifier",
+        db_constraint=False,
     )
     decision = models.ForeignKey(ImageDecision, on_delete=models.CASCADE)
 

api/api/models/media.py

@@ -352,8 +352,9 @@ class AbstractMediaDecisionThrough(models.Model):
     media_obj = models.ForeignKey(
         AbstractMedia,
         to_field="identifier",
-        on_delete=models.CASCADE,
+        on_delete=models.DO_NOTHING,
         db_column="identifier",
+        db_constraint=False,
     )
     decision = models.ForeignKey(AbstractMediaDecision, on_delete=models.CASCADE)
 

api/latest_migrations/api

@@ -2,4 +2,4 @@
 # If you have a merge conflict in this file, it means you need to run:
 #     manage.py makemigrations --merge
 # in order to resolve the conflict between migrations.
-0066_contentsource_delete_contentprovider
+0067_alter_audiodecisionthrough_media_obj_and_more