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/models/language/pooling/embed_utils.py

@@ -0,0 +1,81 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+from collections.abc import Sequence
+
+import openai
+import pytest
+
+from tests.conftest import HfRunner
+from tests.models.utils import EmbedModelInfo, check_embeddings_close, matryoshka_fy
+
+
+def run_embedding_correctness_test(
+    hf_model: "HfRunner",
+    inputs: list[str],
+    vllm_outputs: Sequence[list[float]],
+    dimensions: int | None = None,
+):
+    hf_outputs = hf_model.encode(inputs)
+    if dimensions:
+        hf_outputs = matryoshka_fy(hf_outputs, dimensions)
+
+    check_embeddings_close(
+        embeddings_0_lst=hf_outputs,
+        embeddings_1_lst=vllm_outputs,
+        name_0="hf",
+        name_1="vllm",
+        tol=1e-2,
+    )
+
+
+def correctness_test_embed_models(
+    hf_runner,
+    vllm_runner,
+    model_info: EmbedModelInfo,
+    example_prompts,
+    vllm_extra_kwargs=None,
+    hf_model_callback=None,
+):
+    pytest.skip("Debug only, ci prefers to use mteb test.")
+
+    # The example_prompts has ending "\n", for example:
+    # "Write a short story about a robot that dreams for the first time.\n"
+    # sentence_transformers will strip the input texts, see:
+    # https://github.com/UKPLab/sentence-transformers/blob/v3.1.1/sentence_transformers/models/Transformer.py#L159
+    # This makes the input_ids different between hf_model and vllm_model.
+    # So we need to strip the input texts to avoid test failing.
+    example_prompts = [str(s).strip() for s in example_prompts]
+
+    vllm_extra_kwargs = vllm_extra_kwargs or {}
+    vllm_extra_kwargs["dtype"] = model_info.dtype
+
+    if model_info.hf_overrides is not None:
+        vllm_extra_kwargs["hf_overrides"] = model_info.hf_overrides
+
+    with vllm_runner(
+        model_info.name, runner="pooling", max_model_len=None, **vllm_extra_kwargs
+    ) as vllm_model:
+        vllm_outputs = vllm_model.embed(example_prompts)
+
+    with hf_runner(
+        model_info.name,
+        dtype=model_info.hf_dtype,
+        is_sentence_transformer=True,
+    ) as hf_model:
+        if hf_model_callback is not None:
+            hf_model_callback(hf_model)
+
+        run_embedding_correctness_test(hf_model, example_prompts, vllm_outputs)
+
+
+async def run_client_embeddings(
+    client: openai.AsyncOpenAI,
+    model_name: str,
+    queries: list[str],
+    instruction: str = "",
+) -> list[list[float]]:
+    outputs = await client.embeddings.create(
+        model=model_name,
+        input=[instruction + q for q in queries],
+    )
+    return [data.embedding for data in outputs.data]