models/migrations/v1_27/v345.go

@@ -29,6 +29,11 @@ func MigrateCustomFieldsToOrgLevel(x *xorm.Engine) error {
 	}
 
 	// Migrate existing data: copy issue_id to entity_id where entity_id is 0
-	_, err := x.Exec("UPDATE custom_field_value SET entity_id = issue_id WHERE entity_id = 0 AND issue_id != 0")
+	if _, err := x.Exec("UPDATE custom_field_value SET entity_id = issue_id WHERE entity_id = 0 AND issue_id != 0"); err != nil {
+		return err
+	}
+
+	// Set issue_id default to 0 so new inserts don't require it
+	_, err := x.Exec("ALTER TABLE custom_field_value MODIFY COLUMN issue_id bigint NOT NULL DEFAULT 0")
 	return err
 }