test(cascade_delete): regression test for status-based cascade filter

Greptile P3 (regression coverage): the cascade filter in
delete_agent was changed from terminated_at is None to
status not in SESSION_TERMINAL_STATUSES in commit a0015e8564.
Add an explicit test that exercises the bug surface — a session
flipped to error (terminal) but with terminated_at deliberately
left None. The legacy filter would have re-terminated it; the
status-based filter must skip it.

tests/test_litellm/proxy/agent_session_endpoints/test_cascade_delete.py

@@ -6,6 +6,7 @@ provider.terminate.
 """
 
 from litellm.proxy.agent_session_endpoints.constants import (
+    SESSION_STATUS_ERROR,
     SESSION_STATUS_TERMINATED,
 )
 
@@ -54,6 +55,64 @@ def test_delete_agent_terminates_sessions_and_calls_provider(
     assert sess_b["id"] in terminate_session_ids
 
 
+def test_delete_agent_skips_session_already_in_terminal_status(
+    client, noop_provider, fake_prisma_client
+):
+    """Greptile P3 (regression): the cascade filter must use
+    ``status not in SESSION_TERMINAL_STATUSES`` rather than
+    ``terminated_at is None``. A session whose status was flipped to
+    ``error`` (terminal) but whose ``terminated_at`` was never written
+    must NOT be re-terminated by the cascade — that would double-fire
+    ``provider.terminate`` and confuse the audit trail.
+    """
+    agent = client.post(
+        "/v2/agents",
+        headers={"Authorization": "Bearer k"},
+        json={"name": "t", "model": "gpt-4"},
+    ).json()
+    aid = agent["id"]
+
+    # An "active" session that should still get terminated by the cascade.
+    sess_active = client.post(
+        "/v2/sessions",
+        headers={"Authorization": "Bearer k"},
+        json={"agent_id": aid, "repos": []},
+    ).json()
+    # A session whose status was already flipped to ``error`` (terminal)
+    # but with ``terminated_at`` deliberately left None — the legacy
+    # filter would have re-terminated this row, but the status-based
+    # filter should skip it.
+    sess_already_terminal = client.post(
+        "/v2/sessions",
+        headers={"Authorization": "Bearer k"},
+        json={"agent_id": aid, "repos": []},
+    ).json()
+    terminal_row = next(
+        r
+        for r in fake_prisma_client.db.litellm_agentsession.rows
+        if r.id == sess_already_terminal["id"]
+    )
+    terminal_row.status = SESSION_STATUS_ERROR
+    terminal_row.terminated_at = None  # explicit — this is the bug surface
+
+    # Reset terminate_calls so we can isolate what cascade fires.
+    noop_provider.terminate_calls.clear()
+
+    res = client.delete(f"/v2/agents/{aid}", headers={"Authorization": "Bearer k"})
+    assert res.status_code == 200
+
+    # Only the active session should have been routed through
+    # provider.terminate; the already-terminal one must be skipped.
+    terminate_session_ids = {c["session_id"] for c in noop_provider.terminate_calls}
+    assert sess_active["id"] in terminate_session_ids
+    assert (
+        sess_already_terminal["id"] not in terminate_session_ids
+    ), "cascade re-terminated a session that was already in a terminal status"
+
+    # The already-terminal session's status must be unchanged.
+    assert terminal_row.status == SESSION_STATUS_ERROR
+
+
 def test_delete_session_terminates_active_runs(
     client, noop_provider, fake_prisma_client
 ):