fix: resolve import issue when running with vllm 0.8.4

Signed-off-by: Jade Zheng <zheng.shoujian@outlook.com>

Author: jianzs

vllm_ascend/worker/model_runner_v1.py

@@ -32,8 +32,6 @@
 from vllm.attention import AttentionType, get_attn_backend
 from vllm.attention.layer import Attention
 from vllm.config import CompilationLevel, VllmConfig
-from vllm.distributed.kv_transfer import (get_kv_transfer_group,
-                                          has_kv_transfer_group)
 from vllm.distributed.parallel_state import get_pp_group
 from vllm.forward_context import set_forward_context
 from vllm.inputs import INPUT_REGISTRY
@@ -57,6 +55,17 @@
 from vllm_ascend.attention.attention_v1 import AscendAttentionState
 from vllm_ascend.platform import NPUPlatform
 
+if vllm_version_is("0.8.4"):
+    from vllm.distributed import get_kv_transfer_group
+
+    def has_kv_transfer_group() -> bool:
+        # vLLM 0.8.4 does not support disaggregated prefill. This function is
+        # added to ensure compatibility with vLLM 0.8.4.
+        return False
+else:
+    from vllm.distributed.kv_transfer import (  # type: ignore
+        get_kv_transfer_group, has_kv_transfer_group)
+
 if TYPE_CHECKING:
     import xgrammar as xgr  # type: ignore[import-untyped]
     from vllm.v1.core.sched.output import SchedulerOutput