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/test_ray_env.py

@@ -0,0 +1,194 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""Tests for vllm.ray.ray_env — env var propagation to Ray workers."""
+
+import os
+from unittest.mock import patch
+
+from vllm.ray.ray_env import get_env_vars_to_copy
+
+# ---------------------------------------------------------------------------
+# Default prefix matching
+# ---------------------------------------------------------------------------
+
+
+class TestDefaultPrefixes:
+    """Built-in prefixes (VLLM_, LMCACHE_, NCCL_, UCX_, HF_, HUGGING_FACE_)
+    should be forwarded without any extra configuration."""
+
+    @patch.dict(os.environ, {"LMCACHE_LOCAL_CPU": "True"}, clear=False)
+    def test_lmcache_prefix(self):
+        result = get_env_vars_to_copy()
+        assert "LMCACHE_LOCAL_CPU" in result
+
+    @patch.dict(os.environ, {"NCCL_DEBUG": "INFO"}, clear=False)
+    def test_nccl_prefix(self):
+        result = get_env_vars_to_copy()
+        assert "NCCL_DEBUG" in result
+
+    @patch.dict(os.environ, {"UCX_TLS": "rc"}, clear=False)
+    def test_ucx_prefix(self):
+        result = get_env_vars_to_copy()
+        assert "UCX_TLS" in result
+
+    @patch.dict(os.environ, {"HF_TOKEN": "secret"}, clear=False)
+    def test_hf_token_via_prefix(self):
+        result = get_env_vars_to_copy()
+        assert "HF_TOKEN" in result
+
+    @patch.dict(os.environ, {"HUGGING_FACE_HUB_TOKEN": "secret"}, clear=False)
+    def test_hugging_face_prefix(self):
+        result = get_env_vars_to_copy()
+        assert "HUGGING_FACE_HUB_TOKEN" in result
+
+
+# ---------------------------------------------------------------------------
+# Default extra vars
+# ---------------------------------------------------------------------------
+
+
+class TestDefaultExtraVars:
+    """Individual vars listed in VLLM_RAY_EXTRA_ENV_VARS_TO_COPY's default."""
+
+    def test_pythonhashseed_in_result(self):
+        """PYTHONHASHSEED should always be in the result set (as a name to
+        copy) regardless of whether it is actually set in os.environ."""
+        result = get_env_vars_to_copy()
+        assert "PYTHONHASHSEED" in result
+
+
+# ---------------------------------------------------------------------------
+# User-supplied extensions
+# ---------------------------------------------------------------------------
+
+
+class TestUserExtensions:
+    """Users can add prefixes and extra vars at deploy time."""
+
+    @patch.dict(
+        os.environ,
+        {
+            "VLLM_RAY_EXTRA_ENV_VAR_PREFIXES_TO_COPY": "MYLIB_",
+            "MYLIB_FOO": "bar",
+        },
+        clear=False,
+    )
+    def test_user_prefix(self):
+        """User-supplied prefixes are additive — built-in defaults are kept."""
+        result = get_env_vars_to_copy()
+        assert "MYLIB_FOO" in result
+
+    @patch.dict(
+        os.environ,
+        {
+            "VLLM_RAY_EXTRA_ENV_VARS_TO_COPY": "MY_SECRET",
+            "MY_SECRET": "val",
+        },
+        clear=False,
+    )
+    def test_user_extra_var(self):
+        """User-supplied extras are additive — PYTHONHASHSEED still included."""
+        result = get_env_vars_to_copy()
+        assert "MY_SECRET" in result
+        assert "PYTHONHASHSEED" in result
+
+
+# ---------------------------------------------------------------------------
+# Exclusion
+# ---------------------------------------------------------------------------
+
+
+class TestExclusion:
+    """exclude_vars and RAY_NON_CARRY_OVER_ENV_VARS take precedence."""
+
+    @patch.dict(os.environ, {"CUDA_VISIBLE_DEVICES": "0,1"}, clear=False)
+    def test_exclude_vars(self):
+        result = get_env_vars_to_copy(exclude_vars={"CUDA_VISIBLE_DEVICES"})
+        assert "CUDA_VISIBLE_DEVICES" not in result
+
+    @patch.dict(os.environ, {"LMCACHE_LOCAL_CPU": "True"}, clear=False)
+    @patch(
+        "vllm.ray.ray_env.RAY_NON_CARRY_OVER_ENV_VARS",
+        {"LMCACHE_LOCAL_CPU"},
+    )
+    def test_non_carry_over_blacklist(self):
+        result = get_env_vars_to_copy()
+        assert "LMCACHE_LOCAL_CPU" not in result
+
+
+# ---------------------------------------------------------------------------
+# additional_vars (platform extension point)
+# ---------------------------------------------------------------------------
+
+
+class TestAdditionalVars:
+    """The additional_vars parameter supports platform-specific vars."""
+
+    @patch.dict(os.environ, {"CUSTOM_PLATFORM_VAR": "1"}, clear=False)
+    def test_additional_vars_passthrough(self):
+        result = get_env_vars_to_copy(additional_vars={"CUSTOM_PLATFORM_VAR"})
+        assert "CUSTOM_PLATFORM_VAR" in result
+
+
+# ---------------------------------------------------------------------------
+# Edge cases
+# ---------------------------------------------------------------------------
+
+
+class TestEdgeCases:
+    """Prefix matching should be strict (startswith, not contains)."""
+
+    @patch.dict(os.environ, {"LMCACH_TYPO": "1"}, clear=False)
+    def test_prefix_no_partial_match(self):
+        """'LMCACH_' does not match the 'LMCACHE_' prefix."""
+        result = get_env_vars_to_copy()
+        assert "LMCACH_TYPO" not in result
+
+    @patch.dict(
+        os.environ,
+        {
+            "VLLM_RAY_EXTRA_ENV_VAR_PREFIXES_TO_COPY": " MYLIB_ , OTHER_ ",
+        },
+        clear=False,
+    )
+    def test_csv_whitespace_handling(self):
+        """Whitespace around commas and tokens should be stripped."""
+        result = get_env_vars_to_copy()
+        # MYLIB_ and OTHER_ should be parsed as valid prefixes — no crash
+        assert isinstance(result, set)
+
+    @patch.dict(
+        os.environ,
+        {
+            "VLLM_RAY_EXTRA_ENV_VAR_PREFIXES_TO_COPY": "MYLIB_",
+            "LMCACHE_BACKEND": "cpu",
+            "NCCL_DEBUG": "INFO",
+            "MYLIB_FOO": "bar",
+        },
+        clear=False,
+    )
+    def test_user_prefix_additive(self):
+        """Setting VLLM_RAY_EXTRA_ENV_VAR_PREFIXES_TO_COPY does NOT drop defaults."""
+        result = get_env_vars_to_copy()
+        # Built-in defaults still present
+        assert "LMCACHE_BACKEND" in result
+        assert "NCCL_DEBUG" in result
+        # User addition also present
+        assert "MYLIB_FOO" in result
+
+    @patch.dict(
+        os.environ,
+        {
+            "VLLM_RAY_EXTRA_ENV_VARS_TO_COPY": "MY_FLAG",
+            "PYTHONHASHSEED": "42",
+            "MY_FLAG": "1",
+        },
+        clear=False,
+    )
+    def test_user_extra_additive(self):
+        """Setting VLLM_RAY_EXTRA_ENV_VARS_TO_COPY does NOT drop defaults."""
+        result = get_env_vars_to_copy()
+        # Built-in default still present
+        assert "PYTHONHASHSEED" in result
+        # User addition also present
+        assert "MY_FLAG" in result