[Doc] Add --force-overwrite option to generate_cmake_presets.py (#24375)

Signed-off-by: elvischenv <219235043+elvischenv@users.noreply.github.com>

docs/contributing/incremental_build.md

@@ -40,6 +40,16 @@ python tools/generate_cmake_presets.py
 
 The script will prompt you if it cannot automatically determine certain paths (e.g., `nvcc` or a specific Python executable for your vLLM development environment). Follow the on-screen prompts. If an existing `CMakeUserPresets.json` is found, the script will ask for confirmation before overwriting it.
 
+**Force overwrite existing file:**
+
+To automatically overwrite an existing `CMakeUserPresets.json` without prompting, use the `--force-overwrite` flag:
+
+```console
+python tools/generate_cmake_presets.py --force-overwrite
+```
+
+This is particularly useful in automated scripts or CI/CD environments where interactive prompts are not desired.
+
 After running the script, a `CMakeUserPresets.json` file will be created in the root of your vLLM repository.
 
 ### Example `CMakeUserPresets.json`

tools/generate_cmake_presets.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+import argparse
 import json
 import multiprocessing
 import os
@@ -26,7 +27,8 @@ def get_cpu_cores():
     return multiprocessing.cpu_count()
 
 
-def generate_presets(output_path="CMakeUserPresets.json"):
+def generate_presets(output_path="CMakeUserPresets.json",
+                     force_overwrite=False):
     """Generates the CMakeUserPresets.json file."""
 
     print("Attempting to detect your system configuration...")
@@ -143,12 +145,15 @@ def generate_presets(output_path="CMakeUserPresets.json"):
     output_file_path = os.path.join(project_root, output_path)
 
     if os.path.exists(output_file_path):
-        overwrite = input(
-            f"'{output_file_path}' already exists. Overwrite? (y/N): ").strip(
-            ).lower()
-        if overwrite != 'y':
-            print("Generation cancelled.")
-            return
+        if force_overwrite:
+            print(f"Overwriting existing file '{output_file_path}'")
+        else:
+            overwrite = input(
+                f"'{output_file_path}' already exists. Overwrite? (y/N): "
+            ).strip().lower()
+            if overwrite != 'y':
+                print("Generation cancelled.")
+                return
 
     try:
         with open(output_file_path, "w") as f:
@@ -166,4 +171,12 @@ def generate_presets(output_path="CMakeUserPresets.json"):
 
 
 if __name__ == "__main__":
-    generate_presets()
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--force-overwrite",
+        action="store_true",
+        help="Force overwrite existing CMakeUserPresets.json without prompting"
+    )
+
+    args = parser.parse_args()
+    generate_presets(force_overwrite=args.force_overwrite)