[Bugfix] Fix chat template loading (#15143)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>
Signed-off-by: Roger Wang <ywang@roblox.com>
Co-authored-by: chaunceyjiang <chaunceyjiang@gmail.com>
Co-authored-by: Roger Wang <ywang@roblox.com>

tests/entrypoints/test_chat_utils.py

@@ -4,10 +4,13 @@ import warnings
 from typing import Optional
 
 import pytest
+from packaging.version import Version
+from transformers import __version__ as TRANSFORMERS_VERSION
 
 from vllm.assets.image import ImageAsset
 from vllm.config import ModelConfig
-from vllm.entrypoints.chat_utils import (_try_extract_ast, load_chat_template,
+from vllm.entrypoints.chat_utils import (_resolve_hf_chat_template,
+                                         _try_extract_ast, load_chat_template,
                                          parse_chat_messages,
                                          parse_chat_messages_futures,
                                          resolve_chat_template_content_format)
@@ -23,8 +26,10 @@ EXAMPLES_DIR = VLLM_PATH / "examples"
 PHI3V_MODEL_ID = "microsoft/Phi-3.5-vision-instruct"
 ULTRAVOX_MODEL_ID = "fixie-ai/ultravox-v0_5-llama-3_2-1b"
 QWEN2VL_MODEL_ID = "Qwen/Qwen2-VL-2B-Instruct"
+QWEN25VL_MODEL_ID = "Qwen/Qwen2.5-VL-3B-Instruct"
 MLLAMA_MODEL_ID = "meta-llama/Llama-3.2-11B-Vision-Instruct"
 LLAMA_GUARD_MODEL_ID = "meta-llama/Llama-Guard-3-1B"
+HERMES_MODEL_ID = "NousResearch/Hermes-3-Llama-3.1-8B"
 
 
 @pytest.fixture(scope="function")
@@ -703,25 +708,27 @@ def test_multimodal_image_parsing_matches_hf(model, image_url):
 
     vllm_result = apply_hf_chat_template(
         tokenizer,
+        trust_remote_code=model_config.trust_remote_code,
         conversation=conversation,
         chat_template=None,
+        tools=None,
         add_generation_prompt=True,
     )
 
     assert hf_result == vllm_result
 
 
-# yapf: disable
 @pytest.mark.parametrize(
-    ("model", "expected_format"),
-    [(PHI3V_MODEL_ID, "string"),
-     (QWEN2VL_MODEL_ID, "openai"),
-     (ULTRAVOX_MODEL_ID, "string"),
-     (MLLAMA_MODEL_ID, "openai"),
-     (LLAMA_GUARD_MODEL_ID, "openai")],
-)
-# yapf: enable
-def test_resolve_content_format_hf_defined(model, expected_format):
+    "model",
+    [
+        QWEN2VL_MODEL_ID,  # tokenizer.chat_template is of type str
+        HERMES_MODEL_ID,  # tokenizer.chat_template is of type dict
+    ])
+@pytest.mark.parametrize("use_tools", [True, False])
+def test_resolve_hf_chat_template(sample_json_schema, model, use_tools):
+    """checks that chat_template is a dict type for HF models."""
+
+    # Build the tokenizer group and grab the underlying tokenizer
     tokenizer_group = TokenizerGroup(
         model,
         enable_lora=False,
@@ -730,7 +737,56 @@ def test_resolve_content_format_hf_defined(model, expected_format):
     )
     tokenizer = tokenizer_group.tokenizer
 
-    chat_template = tokenizer.chat_template
+    tools = [{
+        "type": "function",
+        "function": {
+            "name": "dummy_function_name",
+            "description": "This is a dummy function",
+            "parameters": sample_json_schema
+        }
+    }] if use_tools else None
+
+    # Test detecting the tokenizer's chat_template
+    chat_template = _resolve_hf_chat_template(
+        tokenizer,
+        chat_template=None,
+        tools=tools,
+        trust_remote_code=True,
+    )
+    assert isinstance(chat_template, str)
+
+
+# yapf: disable
+@pytest.mark.parametrize(
+    ("model", "expected_format"),
+    [(PHI3V_MODEL_ID, "string"),
+     (QWEN2VL_MODEL_ID, "openai"),
+     (QWEN25VL_MODEL_ID, "openai"),
+     (ULTRAVOX_MODEL_ID, "string"),
+     (MLLAMA_MODEL_ID, "openai"),
+     (LLAMA_GUARD_MODEL_ID, "openai")],
+)
+# yapf: enable
+def test_resolve_content_format_hf_defined(model, expected_format):
+    if model == QWEN25VL_MODEL_ID and Version(TRANSFORMERS_VERSION) < Version(
+            "4.49.0"):
+        pytest.skip("Qwen2.5-VL requires transformers>=4.49.0")
+
+    tokenizer_group = TokenizerGroup(
+        model,
+        enable_lora=False,
+        max_num_seqs=5,
+        max_input_length=None,
+    )
+    tokenizer = tokenizer_group.tokenizer
+
+    # Test detecting the tokenizer's chat_template
+    chat_template = _resolve_hf_chat_template(
+        tokenizer,
+        chat_template=None,
+        tools=None,
+        trust_remote_code=True,
+    )
     assert isinstance(chat_template, str)
 
     print("[TEXT]")
@@ -740,8 +796,10 @@ def test_resolve_content_format_hf_defined(model, expected_format):
 
     resolved_format = resolve_chat_template_content_format(
         None,  # Test detecting the tokenizer's chat_template
+        None,
         "auto",
         tokenizer,
+        trust_remote_code=True,
     )
 
     assert resolved_format == expected_format
@@ -791,8 +849,10 @@ def test_resolve_content_format_examples(template_path, expected_format):
 
     resolved_format = resolve_chat_template_content_format(
         chat_template,
+        None,
         "auto",
         dummy_tokenizer,
+        trust_remote_code=True,
     )
 
     assert resolved_format == expected_format