Transformers backend already supports V1 (#15463)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/models/test_transformers.py

@@ -3,8 +3,6 @@
 
 Run `pytest tests/models/test_transformers.py`.
 """
-from contextlib import nullcontext
-
 import pytest
 
 from ..conftest import HfRunner, VllmRunner
@@ -42,7 +40,6 @@ def check_implementation(
     "model,model_impl",
     [
         ("meta-llama/Llama-3.2-1B-Instruct", "transformers"),
-        ("openai-community/gpt2", "transformers"),
         ("ArthurZ/Ilama-3.2-1B", "auto"),  # CUSTOM CODE
     ])  # trust_remote_code=True by default
 def test_models(
@@ -52,20 +49,11 @@ def test_models(
     model: str,
     model_impl: str,
 ) -> None:
-
-    maybe_raises = nullcontext()
-    if model == "openai-community/gpt2" and model_impl == "transformers":
-        # Model is not backend compatible
-        maybe_raises = pytest.raises(
-            ValueError,
-            match="The Transformers implementation.*not compatible with vLLM")
-
-    with maybe_raises:
-        check_implementation(hf_runner,
-                             vllm_runner,
-                             example_prompts,
-                             model,
-                             model_impl=model_impl)
+    check_implementation(hf_runner,
+                         vllm_runner,
+                         example_prompts,
+                         model,
+                         model_impl=model_impl)
 
 
 @multi_gpu_test(num_gpus=2)

vllm/engine/arg_utils.py

@@ -1613,14 +1613,6 @@ class EngineArgs:
                                recommend_to_remove=False)
             return False
 
-        # No TransformersModel support so far.
-        if (model_config.model_impl == ModelImpl.TRANSFORMERS
-                or model_config.model_impl == "transformers"):
-            _raise_or_fallback(
-                feature_name=f"model_impl={model_config.model_impl}",
-                recommend_to_remove=False)
-            return False
-
         # No Concurrent Partial Prefills so far.
         if (self.max_num_partial_prefills
                 != EngineArgs.max_num_partial_prefills

vllm/model_executor/models/transformers.py

@@ -24,6 +24,7 @@ from transformers import AutoModel, PretrainedConfig, PreTrainedModel
 from transformers.modeling_utils import ALL_ATTENTION_FUNCTIONS
 
 from vllm.attention import Attention
+from vllm.compilation.decorators import support_torch_compile
 from vllm.config import (CacheConfig, DeviceConfig, ModelConfig,
                          ParallelConfig, VllmConfig)
 from vllm.distributed import get_pp_group, get_tensor_model_parallel_world_size
@@ -109,6 +110,7 @@ def replace_linear_class(
     )
 
 
+@support_torch_compile
 class TransformersModel(nn.Module, SupportsQuant, SupportsLoRA, SupportsPP):
     embedding_padding_modules = ["lm_head"]
     embedding_modules = ["embed_tokens"