fix: make initial deposit backfill defensive against subsidy-less ledgers

enterprise_subsidy/apps/subsidy/migrations/0022_backfill_initial_deposits.py

@@ -7,18 +7,23 @@
 Note this has no reverse migration logic. Attempts to rollback the deployment which includes this PR will not delete
 (un-backfill) the deposits created during the forward migration.
 """
+import logging
+
 import django.utils.timezone
 from django.db import migrations
 
 from enterprise_subsidy.apps.subsidy.migration_utils import find_legacy_initial_transactions
 from enterprise_subsidy.apps.subsidy.models import SubsidyReferenceChoices
 
+logger = logging.getLogger(__name__)
+
 
 def forwards_func(apps, schema_editor):
     """
     The core logic of this migration.
     """
     # We get the models from the versioned app registry; if we directly import it, it'll be the wrong version.
+    Ledger = apps.get_model("openedx_ledger", "Ledger")
     Transaction = apps.get_model("openedx_ledger", "Transaction")
     Deposit = apps.get_model("openedx_ledger", "Deposit")
     HistoricalDeposit = apps.get_model("openedx_ledger", "HistoricalDeposit")
@@ -44,12 +49,22 @@ def forwards_func(apps, schema_editor):
     deposits_to_backfill = []
     historical_deposits_to_backfill = []
     for tx in legacy_initial_transactions:
+        sales_contract_reference_id = None
+        sales_contract_reference_provider = None
+        try:
+            sales_contract_reference_id = tx.ledger.subsidy.reference_id
+            sales_contract_reference_provider = sales_contract_reference_providers[tx.ledger.subsidy.reference_type]
+        except Ledger.subsidy.RelatedObjectDoesNotExist:
+            logger.warning(
+                "Found a ledger (%s) without a related subsidy, so the initial deposit will not have a sales contract.",
+                tx.ledger.uuid,
+            )
         deposit_fields = {
             "ledger": tx.ledger,
             "transaction": tx,
             "desired_deposit_quantity": tx.quantity,
-            "sales_contract_reference_id": tx.ledger.subsidy.reference_id,
-            "sales_contract_reference_provider": sales_contract_reference_providers[tx.ledger.subsidy.reference_type],
+            "sales_contract_reference_id": sales_contract_reference_id,
+            "sales_contract_reference_provider": sales_contract_reference_provider,
         }
         deposit = Deposit(**deposit_fields)
         historical_deposit = HistoricalDeposit(

enterprise_subsidy/apps/subsidy/tests/test_migrations.py

@@ -11,15 +11,22 @@
 
 @pytest.mark.django_db
 @pytest.mark.parametrize(
-    "initial_deposit_exists,subsidy_reference_id",
+    "initial_deposit_exists,subsidy_exists,subsidy_reference_id",
     [
-        (False, None),
-        (False, "abc123"),
-        (True, None),
-        (True, "abc123"),
+        (False, False, None),
+        (False, True,  None),
+        (False, True,  "abc123"),
+        (True,  False, None),
+        (True,  True,  None),
+        (True,  True,  "abc123"),
     ],
 )
-def test_migration_0022_backfill_initial_deposits(migrator, initial_deposit_exists, subsidy_reference_id):
+def test_migration_0022_backfill_initial_deposits(
+    migrator,
+    initial_deposit_exists,
+    subsidy_exists,
+    subsidy_reference_id,
+):
     """
     Test Backfilling initial deposits via data migration.
     """
@@ -36,23 +43,27 @@ def test_migration_0022_backfill_initial_deposits(migrator, initial_deposit_exis
     SalesContractReferenceProvider = old_state.apps.get_model("openedx_ledger", "SalesContractReferenceProvider")
 
     ledger = Ledger.objects.create()
-    subsidy = Subsidy.objects.create(
-        ledger=ledger,
-        starting_balance=100,
-        reference_id=subsidy_reference_id,
-        enterprise_customer_uuid=uuid.uuid4(),
-    )
+    subsidy = None
+    if subsidy_exists:
+        subsidy = Subsidy.objects.create(
+            ledger=ledger,
+            starting_balance=100,
+            reference_id=subsidy_reference_id,
+            enterprise_customer_uuid=uuid.uuid4(),
+        )
     transaction = Transaction.objects.create(
         ledger=ledger,
         idempotency_key=INITIAL_DEPOSIT_TRANSACTION_SLUG,
-        quantity=subsidy.starting_balance,
+        quantity=subsidy.starting_balance if subsidy_exists else 100,
         state=TransactionStateChoices.COMMITTED
     )
     if initial_deposit_exists:
-        sales_contract_reference_provider = SalesContractReferenceProvider.objects.create(
-            slug=subsidy.reference_type,
-            name="Foo Bar",
-        )
+        sales_contract_reference_provider = None
+        if subsidy_exists:
+            sales_contract_reference_provider = SalesContractReferenceProvider.objects.create(
+                slug=subsidy.reference_type,
+                name="Foo Bar",
+            )
         Deposit.objects.create(
             ledger=ledger,
             desired_deposit_quantity=transaction.quantity,
@@ -83,14 +94,23 @@ def test_migration_0022_backfill_initial_deposits(migrator, initial_deposit_exis
 
     # Finally check that all the deposit values are correct.
     assert Deposit.objects.first().ledger.uuid == ledger.uuid
-    assert Deposit.objects.first().desired_deposit_quantity == subsidy.starting_balance
+    assert Deposit.objects.first().desired_deposit_quantity == 100
     assert Deposit.objects.first().transaction.uuid == transaction.uuid
-    assert Deposit.objects.first().sales_contract_reference_id == subsidy_reference_id
-    assert Deposit.objects.first().sales_contract_reference_provider.slug == subsidy.reference_type
+    if subsidy_exists:
+        assert Deposit.objects.first().sales_contract_reference_id == subsidy_reference_id
+        assert Deposit.objects.first().sales_contract_reference_provider.slug == subsidy.reference_type
+    else:
+        assert Deposit.objects.first().sales_contract_reference_id is None
+        assert Deposit.objects.first().sales_contract_reference_provider is None
+
     assert HistoricalDeposit.objects.first().ledger.uuid == ledger.uuid
-    assert HistoricalDeposit.objects.first().desired_deposit_quantity == subsidy.starting_balance
+    assert HistoricalDeposit.objects.first().desired_deposit_quantity == 100
     assert HistoricalDeposit.objects.first().transaction.uuid == transaction.uuid
-    assert HistoricalDeposit.objects.first().sales_contract_reference_id == subsidy_reference_id
-    assert HistoricalDeposit.objects.first().sales_contract_reference_provider.slug == subsidy.reference_type
+    if subsidy_exists:
+        assert HistoricalDeposit.objects.first().sales_contract_reference_id == subsidy_reference_id
+        assert HistoricalDeposit.objects.first().sales_contract_reference_provider.slug == subsidy.reference_type
+    else:
+        assert HistoricalDeposit.objects.first().sales_contract_reference_id is None
+        assert HistoricalDeposit.objects.first().sales_contract_reference_provider is None
     assert HistoricalDeposit.objects.first().history_type == "+"
     assert HistoricalDeposit.objects.first().history_change_reason == "Data migration to backfill initial deposits"