[Build] Add srt_empty extra group for device-agnostic install (#31300)

Co-authored-by: yixiaodapeng <yixiaodapeng@example.com>
Co-authored-by: Alex Nails <alex.nails@radixark.ai>

python/pyproject_other.toml

@@ -17,14 +17,16 @@ classifiers = [
 dependencies = ["aiohttp", "IPython", "numpy", "requests", "setproctitle", "tqdm"]
 
 [project.optional-dependencies]
-runtime_common = [
+# runtime_base: torch-free subset of runtime_common.
+# Used by srt_empty for device-agnostic install on non-NVIDIA platforms.
+# NOTE: Do NOT add packages that depend on torch/triton here — they belong in runtime_common.
+runtime_base = [
   "aiohttp",
   "anthropic>=0.20.0",
   "apache-tvm-ffi",
   "av",
   "blobfile==3.0.0",
   "build",
-  "compressed-tensors",
   "datasets",
   "easydict",
   "einops",
@@ -42,7 +44,6 @@ runtime_common = [
   "openai==2.6.1",
   "openai-harmony==0.0.4",
   "orjson",
-  "outlines==0.1.11",
   "packaging",
   "partial_json_parser",
   "pillow",
@@ -60,16 +61,29 @@ runtime_common = [
   "smg-grpc-servicer>=0.5.0",
   "soundfile==0.13.1",
   "tiktoken",
-  "timm==1.0.16",
-  "torchao==0.9.0",
   "tqdm",
   "transformers==5.12.1",
   "uvicorn",
   "uvloop",
   "xxhash",
+]
+
+# runtime_common: backward-compatible — same install result as before the split.
+runtime_common = [
+  "sglang[runtime_base]",
+  "compressed-tensors",
+  "outlines==0.1.11",
+  "timm==1.0.16",
+  "torchao==0.9.0",
   "xgrammar==0.2.1",
 ]
 
+# srt_empty: device-agnostic install — pure Python packages only, no torch dependency chain.
+# Enables OOT plugins (e.g. sglang-plugin-FL) to install sglang without conflicting with
+# vendor-specific PyTorch builds (torch_npu, torch_musa, etc.).
+# Usage: cp pyproject_other.toml pyproject.toml && pip install -e ".[srt_empty]"
+srt_empty = ["sglang[runtime_base]"]
+
 diffusion_common = [
   "addict",
   "cloudpickle",