[Misc] Replace Optional[X] with X | None syntax (#33332)

Signed-off-by: carlory <baofa.fan@daocloud.io>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

vllm/v1/attention/backends/mla/flashmla_sparse.py

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, ClassVar, Optional
+from typing import TYPE_CHECKING, ClassVar
 
 import numpy as np
 import torch
@@ -707,7 +707,7 @@ class FlashMLASparseImpl(MLACommonBaseImpl[FlashMLASparseMetadata]):
         kv_sharing_target_layer_name: str | None,
         # MLA Specific Arguments
         topk_indice_buffer: torch.Tensor | None = None,
-        indexer: Optional["Indexer"] = None,
+        indexer: "Indexer | None" = None,
         **mla_args,
     ) -> None:
         super().__init__(

vllm/v1/attention/backends/mla/rocm_aiter_mla_sparse.py

@@ -2,7 +2,7 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, ClassVar, Optional
+from typing import TYPE_CHECKING, ClassVar
 
 import numpy as np
 import torch
@@ -284,7 +284,7 @@ class ROCMAiterMLASparseImpl(MLACommonBaseImpl[ROCMAiterMLASparseMetadata]):
         kv_sharing_target_layer_name: str | None,
         # MLA Specific Arguments
         topk_indice_buffer: torch.Tensor | None = None,
-        indexer: Optional["Indexer"] = None,
+        indexer: "Indexer | None" = None,
         **mla_args,
     ) -> None:
         super().__init__(

vllm/v1/attention/backends/tree_attn.py

@@ -4,7 +4,7 @@
 
 import ast
 from dataclasses import dataclass
-from typing import ClassVar, Optional
+from typing import ClassVar
 
 import torch
 
@@ -87,11 +87,11 @@ class TreeAttentionMetadata:
     tree_attn_bias: torch.Tensor | None = None
 
     # Cached Prefill/decode metadata.
-    _cached_prefill_metadata: Optional["TreeAttentionMetadata"] = None
-    _cached_decode_metadata: Optional["TreeAttentionMetadata"] = None
+    _cached_prefill_metadata: "TreeAttentionMetadata | None" = None
+    _cached_decode_metadata: "TreeAttentionMetadata | None" = None
 
     @property
-    def prefill_metadata(self) -> Optional["TreeAttentionMetadata"]:
+    def prefill_metadata(self) -> "TreeAttentionMetadata | None":
         if self.num_prefills == 0:
             return None
 
@@ -116,7 +116,7 @@ class TreeAttentionMetadata:
         return self._cached_prefill_metadata
 
     @property
-    def decode_metadata(self) -> Optional["TreeAttentionMetadata"]:
+    def decode_metadata(self) -> "TreeAttentionMetadata | None":
         if self.num_decode_tokens == 0:
             return None