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/kernels/moe/test_flashinfer_moe.py

@@ -0,0 +1,181 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+import pytest
+import torch
+
+from tests.kernels.moe.utils import make_test_quant_config
+from tests.kernels.quantization.nvfp4_utils import (
+    FLOAT4_E2M1_MAX,
+    FLOAT8_E4M3_MAX,
+    dequantize_nvfp4_to_dtype,
+)
+from tests.kernels.utils import torch_moe
+from vllm import _custom_ops as ops
+from vllm.config import ParallelConfig, VllmConfig, set_current_vllm_config
+from vllm.model_executor.layers.fused_moe import fused_topk
+from vllm.model_executor.layers.fused_moe.activation import MoEActivation
+from vllm.model_executor.layers.fused_moe.all2all_utils import (
+    maybe_make_prepare_finalize,
+)
+from vllm.model_executor.layers.fused_moe.config import (
+    FusedMoEConfig,
+    FusedMoEParallelConfig,
+    RoutingMethodType,
+)
+from vllm.model_executor.layers.fused_moe.flashinfer_cutlass_moe import (
+    FlashInferExperts,
+    is_valid_flashinfer_cutlass_fused_moe,
+)
+from vllm.model_executor.layers.fused_moe.modular_kernel import FusedMoEKernel
+from vllm.platforms import current_platform
+from vllm.utils.flashinfer import has_flashinfer_cutlass_fused_moe
+from vllm.utils.torch_utils import set_random_seed
+
+if not has_flashinfer_cutlass_fused_moe() or not current_platform.has_device_capability(
+    100
+):
+    pytest.skip(
+        "Requires flashinfer_cutlass_fused_moe and nvfp4 support",
+        allow_module_level=True,
+    )
+
+MNK_FACTORS = [
+    (2, 1024, 1024),
+    (2, 3072, 1024),
+    (2, 3072, 1536),
+    (64, 1024, 1536),
+    (64, 3072, 1024),
+    (64, 2048, 1536),
+    (224, 1024, 1024),
+    (224, 1024, 1536),
+]
+
+
+@pytest.mark.parametrize("m,n,k", MNK_FACTORS)
+@pytest.mark.parametrize("e", [40, 64, 256])
+@pytest.mark.parametrize("topk", [1, 6, 8])
+@pytest.mark.parametrize("dtype", [torch.bfloat16])
+@pytest.mark.parametrize("activation", [MoEActivation.SILU, MoEActivation.RELU2_NO_MUL])
+@torch.inference_mode()
+def test_flashinfer_fp4_moe_no_graph(
+    m: int,
+    n: int,
+    k: int,
+    e: int,
+    topk: int,
+    dtype: torch.dtype,
+    activation: MoEActivation,
+    workspace_init,
+):
+    set_random_seed(7)
+    with set_current_vllm_config(
+        VllmConfig(parallel_config=ParallelConfig(pipeline_parallel_size=1))
+    ):
+        a = torch.randn((m, k), device="cuda", dtype=dtype) / 10
+
+        quant_blocksize = 16
+        is_gated_act = activation.is_gated
+
+        w1_q, w2_q, quant_config = make_test_quant_config(
+            e,
+            n,
+            k,
+            in_dtype=dtype,
+            quant_dtype="nvfp4",
+            block_shape=None,
+            per_act_token_quant=False,
+            make_gate=is_gated_act,
+        )
+
+        score = torch.randn((m, e), device="cuda", dtype=dtype)
+        topk_weights, topk_ids, _ = fused_topk(a, score, topk, renormalize=False)
+
+        assert is_valid_flashinfer_cutlass_fused_moe(a, w1_q, w2_q)
+
+        moe_config = FusedMoEConfig(
+            num_experts=e,
+            experts_per_token=topk,
+            hidden_dim=k,
+            intermediate_size_per_partition=n,
+            num_local_experts=e,
+            num_logical_experts=e,
+            activation=activation,
+            device="cuda",
+            moe_parallel_config=FusedMoEParallelConfig.make_no_parallel(),
+            in_dtype=dtype,
+            is_act_and_mul=is_gated_act,
+            routing_method=RoutingMethodType.TopK,
+        )
+
+        flashinfer_experts = FusedMoEKernel(
+            maybe_make_prepare_finalize(
+                moe=moe_config,
+                quant_config=quant_config,
+                allow_new_interface=True,
+                use_monolithic=False,
+            ),
+            FlashInferExperts(moe_config=moe_config, quant_config=quant_config),
+            inplace=False,
+        )
+
+        flashinfer_output = flashinfer_experts.apply(
+            hidden_states=a,
+            w1=w1_q,
+            w2=w2_q,
+            topk_weights=topk_weights,
+            topk_ids=topk_ids,
+            activation=activation,
+            global_num_experts=e,
+            expert_map=None,
+            apply_router_weight_on_input=False,
+        )
+
+        # Reference check:
+        a_global_scale = (
+            (FLOAT8_E4M3_MAX * FLOAT4_E2M1_MAX) / torch.amax(a.flatten(), dim=-1)
+        ).to(torch.float32)
+        a_fp4, a_scale_interleaved = ops.scaled_fp4_quant(a, a_global_scale)
+        _, m_k = a_fp4.shape
+        a_in_dtype = dequantize_nvfp4_to_dtype(
+            a_fp4,
+            a_scale_interleaved,
+            a_global_scale,
+            dtype=a.dtype,
+            device=a.device,
+            block_size=quant_blocksize,
+        )
+
+        w1_d = torch.empty(
+            (e, (2 if is_gated_act else 1) * n, k), device="cuda", dtype=dtype
+        )
+        w2_d = torch.empty((e, k, n), device="cuda", dtype=dtype)
+
+        for idx in range(0, e):
+            w1_d[idx] = dequantize_nvfp4_to_dtype(
+                w1_q[idx],
+                quant_config.w1_scale[idx],
+                (1 / quant_config.g1_alphas[idx]),
+                dtype=dtype,
+                device=w1_q.device,
+                block_size=quant_blocksize,
+            )
+            w2_d[idx] = dequantize_nvfp4_to_dtype(
+                w2_q[idx],
+                quant_config.w2_scale[idx],
+                (1 / quant_config.g2_alphas[idx]),
+                dtype=dtype,
+                device=w2_q.device,
+                block_size=quant_blocksize,
+            )
+
+        torch_output = torch_moe(
+            a_in_dtype, w1_d, w2_d, score, topk, activation=activation
+        )
+
+        torch.testing.assert_close(
+            torch_output, flashinfer_output, atol=1e-1, rtol=1e-1
+        )
+
+
+if __name__ == "__main__":
+    test_flashinfer_fp4_moe_no_graph((2, 1024, 1024), 40, 1, torch.half)