[CI/Build] fix setuptools-scm usage (#8771)

.gitignore

-# vllm commit id, generated by setup.py
-vllm/commit_id.py
+# version file generated by setuptools-scm
+/vllm/_version.py
 
 # vllm-flash-attn built from source
 vllm/vllm_flash_attn/
@@ -196,8 +196,5 @@ _build/
 *_hip*
 hip_compat.h
 
-# version file generated by setuptools-scm
-/vllm/_version.py
-
 # Benchmark dataset
 benchmarks/*.json

pyproject.toml

@@ -51,9 +51,6 @@ ignore = [
     "UP032",
 ]
 
-[tool.setuptools_scm]
-version_file = "vllm/_version.py"
-
 [tool.mypy]
 python_version = "3.8"
 

setup.py

@@ -354,12 +354,15 @@ def get_path(*filepath) -> str:
 
 
 def get_vllm_version() -> str:
-    version = get_version()
+    version = get_version(
+        write_to="vllm/_version.py",  # TODO: move this to pyproject.toml
+    )
+
     sep = "+" if "+" not in version else "."  # dev versions might contain +
 
     if _no_device():
         if envs.VLLM_TARGET_DEVICE == "empty":
-            version += "+empty"
+            version += f"{sep}empty"
     elif _is_cuda():
         cuda_version = str(get_nvcc_cuda_version())
         if cuda_version != MAIN_CUDA_VERSION: