[Core] Add Lora Support to Beam Search (#18346)

Signed-off-by: Alex-Brooks <Alex.Brooks@ibm.com>

vllm/beam_search.py

@@ -3,6 +3,7 @@
 from dataclasses import dataclass
 from typing import TYPE_CHECKING, Any, Optional, Union
 
+from vllm.lora.request import LoRARequest
 from vllm.sequence import Logprob
 
 if TYPE_CHECKING:
@@ -19,6 +20,7 @@ class BeamSearchSequence:
     # The tokens includes the prompt.
     tokens: list[int]
     logprobs: list[dict[int, Logprob]]
+    lora_request: Optional[LoRARequest] = None
     cum_logprob: float = 0.0
     text: Optional[str] = None
     finish_reason: Optional[str] = None
@@ -41,6 +43,7 @@ class BeamSearchInstance:
     def __init__(
         self,
         prompt_tokens: list[int],
+        lora_request: Optional[LoRARequest] = None,
         logprobs: Optional[list[dict[int, Logprob]]] = None,
         **kwargs,
     ):
@@ -48,6 +51,7 @@ class BeamSearchInstance:
             BeamSearchSequence(
                 tokens=prompt_tokens,
                 logprobs=[] if logprobs is None else list(logprobs),
+                lora_request=lora_request,
                 **kwargs,
             )
         ]