From 8408cd94b50856a61c477fe8722e14f34cbd5caa Mon Sep 17 00:00:00 2001
From: lewis <lewis@cobley.io>
Date: Fri, 16 Oct 2026 22:44:03 -0400
Subject: [PATCH] fix(proxy): apply an explicitly sent zero customer budget
 instead of ignoring it

---
 .../proxy/management_endpoints/customer_endpoints.py  |  4 ++--
 .../management_endpoints/test_customer_endpoints.py   | 11 +++++++----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/litellm/proxy/management_endpoints/customer_endpoints.py b/litellm/proxy/management_endpoints/customer_endpoints.py
index 20c6762a9be..65ce424c5e4 100644
--- a/litellm/proxy/management_endpoints/customer_endpoints.py
+++ b/litellm/proxy/management_endpoints/customer_endpoints.py
@@ -92,7 +92,7 @@ _CUSTOMER_UPDATE_LOCK_SQL: Final = 'SELECT "user_id" FROM "LiteLLM_EndUserTable"
 def _should_update_field(field: str, value: object, sent_fields: AbstractSet[str]) -> bool:
     if value is None:
         return False
-    if field in sent_fields and (isinstance(value, bool) or field in _CLEARABLE_LIST_FIELDS):
+    if field in sent_fields and (isinstance(value, (int, float)) or field in _CLEARABLE_LIST_FIELDS):
         return True
     if isinstance(value, (list, dict)) and not value:
         return False
@@ -686,7 +686,7 @@ async def _update_single_customer(
             end_user_table_data_typed: Final = LiteLLM_EndUserTable.model_validate(end_user_table_data.model_dump())
             budget_error: Final = (
                 await _customer_budget_update_error(tx, end_user_table_data_typed.budget_id, data.user_id)
-                if "max_budget" in budget_table_data and end_user_table_data_typed.budget_id is not None
+                if budget_table_data and end_user_table_data_typed.budget_id is not None
                 else None
             )
             if budget_error is not None:
diff --git a/tests/unit/proxy/management_endpoints/test_customer_endpoints.py b/tests/unit/proxy/management_endpoints/test_customer_endpoints.py
index c939814a278..32515d649bc 100644
--- a/tests/unit/proxy/management_endpoints/test_customer_endpoints.py
+++ b/tests/unit/proxy/management_endpoints/test_customer_endpoints.py
@@ -73,7 +73,8 @@ client = TestClient(app)
         ("object_permission", {"mcp_servers": ["s1"]}, frozenset({"object_permission"}), True),
         ("metadata", ["m1"], frozenset(), True),
         ("models", ["m1"], frozenset(), True),
-        ("max_budget", 0, frozenset({"max_budget"}), False),
+        ("max_budget", 0, frozenset({"max_budget"}), True),
+        ("max_budget", 0, frozenset(), False),
         ("max_budget", 5.0, frozenset(), True),
         ("alias", "a", frozenset(), True),
     ),
@@ -89,6 +90,7 @@ client = TestClient(app)
         "nonempty-list-other-field",
         "nonempty-models",
         "zero-budget",
+        "omitted-zero-budget",
         "nonzero-budget",
         "alias",
     ),
@@ -2088,11 +2090,12 @@ def test_customer_budget_update_rejects_shared_references_without_partial_writes
     assert database.locked_budget_ids == {budget.budget_id}
 
 
+@pytest.mark.parametrize("new_max_budget", (100, 0))
 @pytest.mark.parametrize(
     "route", ("/customer/update", "/end_user/update", "/customer/bulk_update", "/end_user/bulk_update")
 )
 def test_customer_budget_update_allows_own_budget_with_unrelated_shared_references(
-    mock_prisma_client: MagicMock, mock_user_api_key_auth: None, route: str
+    mock_prisma_client: MagicMock, mock_user_api_key_auth: None, route: str, new_max_budget: int
 ) -> None:
     own_budget: Final = LiteLLM_BudgetTable(budget_id="own-budget", max_budget=50)
     other_budget: Final = LiteLLM_BudgetTable(budget_id="other-budget", max_budget=75)
@@ -2112,13 +2115,13 @@ def test_customer_budget_update_allows_own_budget_with_unrelated_shared_referenc
         (own_customer, other), budgets=(own_budget, other_budget), budget_references=references
     )
     database.attach(mock_prisma_client)
-    update: Final = {"user_id": own_customer.user_id, "max_budget": 100}
+    update: Final = {"user_id": own_customer.user_id, "max_budget": new_max_budget}
     payload: Final = {"customers": [update]} if route.endswith("bulk_update") else update
     with patch("litellm.max_end_user_budget_id", "other-budget"):
         response: Final = client.post(route, json=payload, headers={"Authorization": "Bearer test-key"})
 
     assert response.status_code == 200, response.text
-    assert database.budgets[own_budget.budget_id].max_budget == 100
+    assert database.budgets[own_budget.budget_id].max_budget == new_max_budget
     assert database.budgets[other_budget.budget_id] == other_budget
     assert database.customers[own_customer.user_id].budget_id == own_budget.budget_id
     assert database.locked_budget_ids == {own_budget.budget_id}