address review: trim verbose comments, fix wrong-request-type assertion

test_load_state_from_db_handles_unknown_request_type compared the
WRITING cell after load against a cold-start value captured for
GENERAL. They happened to be equal for this fixture (the fast model's
empty strengths list makes every request type's prior identical), which
hid that the assertion was comparing the wrong baseline. Capture each
request type's own cold-start value instead.

litellm/router_strategy/adaptive_router/adaptive_router.py

@@ -123,16 +123,11 @@ class AdaptiveRouter:
                 self._cells[(rt, model)] = initial_cell(prefs, rt)
 
     async def load_state_from_db(self, prisma_client: Any) -> None:
-        """Add persisted deltas on top of the cold-start prior for every cell with a row.
+        """Add each row's persisted delta to a freshly computed cold-start prior.
 
-        A DB row holds accumulated deltas only (AdaptiveRouterUpdateQueue.flush_state_to_db
-        creates the row with the raw delta as its initial value, then increments it), never
-        the prior. Assigning `row.alpha`/`row.beta` straight into the cell would silently drop
-        the cold-start prior _init_cold_start_cells already put there, and the first flush after
-        a cell sees only one kind of signal persists a one-sided row (e.g. alpha=1, beta=0) - as
-        a bare Beta(alpha, beta) that zeroes out one shape parameter, which is invalid and 500s
-        on every later thompson_sample() draw for that cell. Adding the row on top of a freshly
-        computed prior keeps both parameters positive, since deltas are never negative.
+        A row holds an accumulated delta, not a full posterior, and can be one-sided
+        (e.g. beta=0) - assigning it straight into the cell would zero out a Beta shape
+        parameter and crash thompson_sample() on every later draw for that cell.
         """
         if prisma_client is None:
             return

tests/test_litellm/router_strategy/adaptive_router/test_adaptive_router.py

@@ -270,10 +270,8 @@ async def test_record_turn_bounds_feedback_contexts_and_evicts_least_recent_sess
 
 @pytest.mark.asyncio
 async def test_load_state_from_db_adds_the_persisted_delta_to_the_cold_start_prior():
-    """A DB row holds an accumulated delta, not a full posterior (AdaptiveRouterUpdateQueue
-    creates the row with the raw delta and increments it from there) - loading it must add
-    that delta on top of the same cold-start prior _init_cold_start_cells already computed,
-    not replace the cell outright."""
+    """A row holds an accumulated delta, not a full posterior; loading must add it to the
+    cold-start prior, not replace the cell outright."""
     r = _make_router()
     cold = r._cells[(RequestType.GENERAL, "fast")]
 
@@ -293,11 +291,8 @@ async def test_load_state_from_db_adds_the_persisted_delta_to_the_cold_start_pri
 
 @pytest.mark.asyncio
 async def test_load_state_from_db_keeps_a_one_sided_delta_row_sampleable():
-    """Regression: a cell whose only DB activity is one signal type persists a one-sided row
-    (e.g. delta_beta=0.0, per AdaptiveRouterUpdateQueue.flush_state_to_db's create branch).
-    Loading that row must not zero out a Beta shape parameter - thompson_sample() raises
-    `ValueError: gammavariate: alpha and beta must be > 0.0` on a zeroed side, bricking every
-    request for that cell until the process restarts."""
+    """A cell whose only DB activity is one signal type persists a one-sided row (e.g.
+    beta=0.0); loading it must not zero out a Beta shape parameter and crash thompson_sample()."""
     from litellm.router_strategy.adaptive_router.bandit import thompson_sample
 
     r = _make_router()
@@ -321,7 +316,8 @@ async def test_load_state_from_db_keeps_a_one_sided_delta_row_sampleable():
 @pytest.mark.asyncio
 async def test_load_state_from_db_handles_unknown_request_type():
     r = _make_router()
-    cold = r._cells[(RequestType.GENERAL, "fast")]
+    cold_general = r._cells[(RequestType.GENERAL, "fast")]
+    cold_writing = r._cells[(RequestType.WRITING, "fast")]
 
     bad_row = MagicMock()
     bad_row.request_type = "nonexistent_type_v999"
@@ -341,9 +337,9 @@ async def test_load_state_from_db_handles_unknown_request_type():
 
     # Unknown skipped; good added to the cold-start prior.
     new_general = r._cells[(RequestType.GENERAL, "fast")]
-    assert new_general.alpha == cold.alpha + 7.0
-    # Other request types kept their cold-start values.
-    assert r._cells[(RequestType.WRITING, "fast")] == cold
+    assert new_general.alpha == cold_general.alpha + 7.0
+    # Other request types kept their own cold-start values.
+    assert r._cells[(RequestType.WRITING, "fast")] == cold_writing
 
 
 # ---- Session state eviction ---------------------------------------------

tests/test_litellm/router_strategy/adaptive_router/test_e2e_adaptive_router.py

@@ -187,10 +187,8 @@ async def test_failure_signal_increments_beta_after_flush():
 
 @pytest.mark.asyncio
 async def test_load_state_from_db_adds_persisted_delta_to_cold_start():
-    """A DB row is an accumulated delta, not a full posterior, so loading it must add onto the
-    same cold-start prior _init_cold_start_cells already computed, not replace the cell outright
-    (see test_adaptive_router.py's version of this test, and the one-sided create row
-    test_failure_signal_increments_beta_after_flush above asserts, for why)."""
+    """A row holds an accumulated delta, not a full posterior; loading must add it to the
+    cold-start prior, not replace the cell outright."""
     router = _make_router()
     cold = router._cells[(RequestType.GENERAL, "gpt-4o")]