[Bugfix] Use LoadFormat values for `vllm serve --load-format` (#7784)

vllm/engine/arg_utils.py

@@ -9,8 +9,8 @@ import torch
 
 import vllm.envs as envs
 from vllm.config import (CacheConfig, DecodingConfig, DeviceConfig,
-                         EngineConfig, LoadConfig, LoRAConfig, ModelConfig,
-                         ObservabilityConfig, ParallelConfig,
+                         EngineConfig, LoadConfig, LoadFormat, LoRAConfig,
+                         ModelConfig, ObservabilityConfig, ParallelConfig,
                          PromptAdapterConfig, SchedulerConfig,
                          SpeculativeConfig, TokenizerPoolConfig)
 from vllm.executor.executor_base import ExecutorBase
@@ -214,10 +214,7 @@ class EngineArgs:
             '--load-format',
             type=str,
             default=EngineArgs.load_format,
-            choices=[
-                'auto', 'pt', 'safetensors', 'npcache', 'dummy', 'tensorizer',
-                'bitsandbytes'
-            ],
+            choices=[f.value for f in LoadFormat],
             help='The format of the model weights to load.\n\n'
             '* "auto" will try to load the weights in the safetensors format '
             'and fall back to the pytorch bin format if safetensors format '