Refactor: Moving extend_logprob_start_len calculation out of prepare_for_extend (#16105)

test/manual/test_forward_split_prefill.py

@@ -92,8 +92,8 @@ class TestForwardSplitPrefill(CustomTestCase):
                 sampling_params=sampling_params,
             )
             req.fill_ids = req.origin_input_ids
-            req.extend_input_len = len(req.fill_ids) - len(req.prefix_indices)
             req.logprob_start_len = -1
+            req.set_extend_input_len(len(req.fill_ids) - len(req.prefix_indices))
             reqs.append(req)
 
         # Create dummy tree_cache for tests (no prefix caching, just allocation)

test/srt/test_prefill_adder.py

@@ -68,6 +68,7 @@ class TestPrefillAdder(CustomTestCase):
         req.rid = str(rid)
         req.priority = priority
         req.extend_input_len = 0
+        req.extend_logprob_start_len = 0
         req.output_ids = [0] * output_len
         req.sampling_params = SimpleNamespace(max_new_tokens=max_new_tokens)
         req.time_stats = SimpleNamespace(wait_queue_entry_time=wait_time)