feat(surveys): add FK constraint for linked_insight_id (#41790)

Author: adboio

posthog/migrations/0913_alter_survey_linked_insight.py

@@ -0,0 +1,40 @@
+# Generated by Django 4.2.26 on 2025-11-20 02:30
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("posthog", "0912_alter_survey_linked_insight_type"),
+    ]
+
+    operations = [
+        migrations.SeparateDatabaseAndState(
+            state_operations=[
+                migrations.AlterField(
+                    model_name="survey",
+                    name="linked_insight",
+                    field=models.ForeignKey(
+                        blank=True,
+                        db_index=False,
+                        null=True,
+                        on_delete=django.db.models.deletion.SET_NULL,
+                        related_name="surveys_linked_insight",
+                        related_query_name="survey_linked_insight",
+                        to="posthog.insight",
+                    ),
+                ),
+            ],
+            database_operations=[
+                migrations.RunSQL(
+                    sql="""
+                        ALTER TABLE "posthog_survey" ADD CONSTRAINT "posthog_survey_linked_insight_id_586524f3_fk_posthog_d" FOREIGN KEY ("linked_insight_id") REFERENCES "posthog_dashboarditem" ("id") DEFERRABLE INITIALLY DEFERRED NOT VALID; -- existing-table-constraint-ignore
+                    """,
+                    reverse_sql="""
+                        ALTER TABLE "posthog_survey" DROP CONSTRAINT IF EXISTS "posthog_survey_linked_insight_id_586524f3_fk_posthog_d";
+                    """,
+                ),
+            ],
+        ),
+    ]

posthog/migrations/max_migration.txt

@@ -1 +1 @@
-0912_alter_survey_linked_insight_type
+0913_alter_survey_linked_insight

posthog/models/surveys/survey.py

@@ -79,7 +79,7 @@ class Meta:
         related_name="surveys_linked_insight",
         related_query_name="survey_linked_insight",
         db_index=False,
-        db_constraint=False,  # Constraint will be added in follow-up migration
+        db_constraint=True,
     )
     internal_targeting_flag = models.ForeignKey(
         "posthog.FeatureFlag",