[Bugfix] Mistral tokenizer encode accept list of str (#12149)

Signed-off-by: Kunshang Ji <kunshang.ji@intel.com>

vllm/transformers_utils/tokenizers/mistral.py

@@ -18,6 +18,7 @@ from mistral_common.tokens.tokenizers.tekken import (SpecialTokenPolicy,
                                                      Tekkenizer)
 
 from vllm.logger import init_logger
+from vllm.utils import is_list_of
 
 if TYPE_CHECKING:
     from vllm.entrypoints.chat_utils import ChatCompletionMessageParam
@@ -27,7 +28,7 @@ logger = init_logger(__name__)
 
 @dataclass
 class Encoding:
-    input_ids: List[int]
+    input_ids: Union[List[int], List[List[int]]]
 
 
 def maybe_serialize_tool_calls(request: ChatCompletionRequest):
@@ -223,17 +224,25 @@ class MistralTokenizer:
 
     def __call__(
         self,
-        prompt: str,
+        prompt: Union[str, List[str], List[int]],
         add_special_tokens: bool = False,
         truncation: bool = False,
         max_length: Optional[int] = None,
     ):
-        # Mistral Tokenizers should not add special tokens
-        input_ids = self.encode(prompt)
-
-        if truncation:
-            input_ids = input_ids[:max_length]
-
+        input_ids: Union[List[int], List[List[int]]]
+        # For List[str], original prompt text
+        if is_list_of(prompt, str):
+            input_ids_: List[List[int]] = []
+            for p in prompt:
+                each_input_ids = self.encode_one(p, truncation, max_length)
+                input_ids_.append(each_input_ids)
+            input_ids = input_ids_
+        # For List[int], apply chat template output, already tokens.
+        elif is_list_of(prompt, int):
+            input_ids = prompt
+        # For str, single prompt text
+        else:
+            input_ids = self.encode_one(prompt, truncation, max_length)
         return Encoding(input_ids=input_ids)
 
     def get_vocab(self) -> Dict[str, int]:
@@ -245,6 +254,19 @@ class MistralTokenizer:
         # Mistral tokenizers have no added vocabulary
         return {}
 
+    def encode_one(
+        self,
+        prompt: str,
+        truncation: bool = False,
+        max_length: Optional[int] = None,
+    ) -> List[int]:
+        # Mistral Tokenizers should not add special tokens
+        input_ids = self.encode(prompt)
+
+        if truncation:
+            input_ids = input_ids[:max_length]
+        return input_ids
+
     def encode(self, prompt: str) -> List[int]:
         # `encode` should only be used for prompt completion
         # it should never be used for chat_completion.