[Misc] Add deprecation warning for beam search (#6402)

vllm/envs.py

@@ -41,6 +41,7 @@ if TYPE_CHECKING:
     NVCC_THREADS: Optional[str] = None
     VLLM_USE_PRECOMPILED: bool = False
     VLLM_INSTALL_PUNICA_KERNELS: bool = False
+    VLLM_NO_DEPRECATION_WARNING: bool = False
     CMAKE_BUILD_TYPE: Optional[str] = None
     VERBOSE: bool = False
 
@@ -251,6 +252,10 @@ environment_variables: Dict[str, Callable[[], Any]] = {
     lambda: os.getenv("VLLM_XLA_CACHE_PATH", "~/.vllm/xla_cache/"),
     "VLLM_FUSED_MOE_CHUNK_SIZE":
     lambda: int(os.getenv("VLLM_FUSED_MOE_CHUNK_SIZE", "65536")),
+
+    # If set, vllm will skip the deprecation warnings.
+    "VLLM_NO_DEPRECATION_WARNING":
+    lambda: bool(int(os.getenv("VLLM_NO_DEPRECATION_WARNING", "0"))),
 }
 
 # end-env-vars-definition