Add vLLM v0.18.1 source tree with KV transfer abort fix

third_party/vllm/ now tracked in git for direct patch management.
Based on vLLM v0.18.1 release with one patch applied:

  vllm/v1/core/sched/scheduler.py:
    Replace fatal assert with graceful skip when KV transfer callback
    arrives for an already-aborted request during PD disaggregated serving.

Future vLLM modifications should be made directly in third_party/vllm/
and committed normally. The patches/ directory is kept as documentation
of what changed from upstream.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

third_party/vllm/tests/reasoning/test_hunyuan_reasoning_parser.py

@@ -0,0 +1,168 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import pytest
+from transformers import AutoTokenizer
+
+from tests.reasoning.utils import run_reasoning_extraction
+from vllm.reasoning import ReasoningParser, ReasoningParserManager
+
+parser_name = "hunyuan_a13b"
+START_REASONING = "<think>\n"
+START_RESPONSE = "\n</think>\n<answer>\n"
+END_RESPONSE = "\n</answer>"
+
+NO_REASONING_QUICK_THOUGHT = {
+    "output": f"{START_REASONING}{START_RESPONSE}This is the rest{END_RESPONSE}",  # noqa: E501
+    "reasoning": None,
+    "content": "This is the rest",
+}
+
+SIMPLE_REASONING = {
+    "output": f"{START_REASONING}This is a reasoning section{START_RESPONSE}This is the rest{END_RESPONSE}",  # noqa: E501
+    "reasoning": "This is a reasoning section",
+    "content": "This is the rest",
+}
+COMPLETE_REASONING = {
+    "output": f"{START_REASONING}This is a reasoning section{START_RESPONSE}",
+    "reasoning": "This is a reasoning section",
+    "content": None,
+}
+
+COMPLETE_REASONING_WITH_SYMBOL = {
+    "output": f"{START_REASONING}This is a reasoning section!{START_RESPONSE}",
+    "reasoning": "This is a reasoning section!",
+    "content": None,
+}
+NO_REASONING = {
+    "output": "This is content",
+    "reasoning": None,
+    "content": "This is content",
+}
+MULTIPLE_LINES = {
+    "output": f"{START_REASONING}This\nThat{START_RESPONSE}This is the rest\nThat",
+    "reasoning": "This\nThat",
+    "content": "This is the rest\nThat",
+}
+REASONING_WITH_THINK = {
+    "output": f"{START_REASONING}This is a reasoning section{START_RESPONSE}This is the rest",  # noqa: E501
+    "reasoning": "This is a reasoning section",
+    "content": "This is the rest",
+}
+COMPLETE_REASONING_WITH_THINK = {
+    "output": f"{START_REASONING}This is a reasoning section{START_RESPONSE}",
+    "reasoning": "This is a reasoning section",
+    "content": None,
+}
+MULTIPLE_LINES_WITH_THINK = {
+    "output": f"{START_REASONING}This\nThat{START_RESPONSE}This is the rest\nThat",
+    "reasoning": "This\nThat",
+    "content": "This is the rest\nThat",
+}
+
+TEST_CASES = [
+    pytest.param(
+        False,
+        SIMPLE_REASONING,
+        id="simple_reasoning",
+    ),
+    pytest.param(
+        False,
+        COMPLETE_REASONING,
+        id="complete_reasoning",
+    ),
+    pytest.param(
+        False,
+        COMPLETE_REASONING_WITH_SYMBOL,
+        id="complete_reasoning_with_symbol",
+    ),
+    pytest.param(
+        False,
+        NO_REASONING,
+        id="no_reasoning",
+    ),
+    pytest.param(False, NO_REASONING_QUICK_THOUGHT, id="no_reasoning_quick"),
+    pytest.param(
+        False,
+        MULTIPLE_LINES,
+        id="multiple_lines",
+    ),
+    pytest.param(
+        False,
+        REASONING_WITH_THINK,
+        id="reasoning_with_think",
+    ),
+    pytest.param(
+        False,
+        COMPLETE_REASONING_WITH_THINK,
+        id="complete_reasoning_with_think",
+    ),
+    pytest.param(
+        False,
+        MULTIPLE_LINES_WITH_THINK,
+        id="multiple_lines_with_think",
+    ),
+    pytest.param(
+        True,
+        SIMPLE_REASONING,
+        id="simple_reasoning_streaming",
+    ),
+    pytest.param(
+        True,
+        COMPLETE_REASONING,
+        id="complete_reasoning_streaming",
+    ),
+    pytest.param(
+        True,
+        NO_REASONING,
+        id="no_reasoning_streaming",
+    ),
+    pytest.param(True, NO_REASONING_QUICK_THOUGHT, id="no_reasoning_quick_stream"),
+    pytest.param(
+        True,
+        MULTIPLE_LINES,
+        id="multiple_lines_streaming",
+    ),
+    pytest.param(
+        True,
+        REASONING_WITH_THINK,
+        id="reasoning_with_think_streaming",
+    ),
+    pytest.param(
+        True,
+        COMPLETE_REASONING_WITH_THINK,
+        id="complete_reasoning_with_think_streaming",
+    ),
+    pytest.param(
+        True,
+        MULTIPLE_LINES_WITH_THINK,
+        id="multiple_lines_with_think_streaming",
+    ),
+]
+
+# Global tokenizer initialization to avoid repeated loading
+tokenizer = AutoTokenizer.from_pretrained(
+    "tencent/Hunyuan-A13B-Instruct", trust_remote_code=True
+)
+
+
+@pytest.mark.parametrize("streaming, param_dict", TEST_CASES)
+def test_reasoning(
+    streaming: bool,
+    param_dict: dict,
+):
+    output = tokenizer.tokenize(param_dict["output"])
+    # decode everything to tokens
+    output_tokens: list[str] = [
+        tokenizer.convert_tokens_to_string([token]) for token in output
+    ]
+    parser: ReasoningParser = ReasoningParserManager.get_reasoning_parser(parser_name)(
+        tokenizer
+    )
+
+    reasoning, content = run_reasoning_extraction(
+        parser, output_tokens, streaming=streaming
+    )
+
+    assert reasoning == param_dict["reasoning"]
+    assert content == param_dict["content"]