[Typing] Mypy typing part 2 (#4043)

Co-authored-by: SangBin Cho <sangcho@sangcho-LT93GQWG9C.local>

vllm/model_executor/guided_decoding/outlines_decoding.py

@@ -55,7 +55,7 @@ global_thread_pool = None  # used for generating logits processor fsm
 
 async def get_outlines_guided_decoding_logits_processor(
         request: Union[CompletionRequest, ChatCompletionRequest],
-        tokenizer) -> Union[JSONLogitsProcessor, RegexLogitsProcessor]:
+        tokenizer) -> Union[JSONLogitsProcessor, RegexLogitsProcessor, None]:
     """
     Given an OpenAI-compatible request, check for guided decoding parameters
     and get the necessary logits processor for the given guide.
@@ -84,7 +84,7 @@ async def get_outlines_guided_decoding_logits_processor(
 
 def _get_guide_and_mode(
     request: Union[CompletionRequest, ChatCompletionRequest]
-) -> Tuple[str, GuidedDecodingMode]:
+) -> Union[Tuple[str, GuidedDecodingMode], Tuple[None, None]]:
 
     if request.guided_json:
         json = request.guided_json

vllm/model_executor/guided_decoding/outlines_logits_processors.py

@@ -21,7 +21,7 @@ from functools import lru_cache
 from typing import Callable, DefaultDict, Dict, List, Optional, Union
 
 import torch
-from outlines.fsm.fsm import CFGFSM, RegexFSM
+from outlines.fsm.fsm import CFGFSM, FSM, RegexFSM
 from outlines.fsm.json_schema import build_regex_from_schema
 from pydantic import BaseModel
 from transformers import PreTrainedTokenizerBase
@@ -29,6 +29,10 @@ from transformers import PreTrainedTokenizerBase
 
 class BaseLogitsProcessor:
 
+    def __init__(self):
+        # Child class should use initialize in their init.
+        self.fsm: FSM
+
     def init_state(self):
         """Initialize the FSM states."""
         self.fsm_state: DefaultDict[int, int] = defaultdict(int)