Allow explicitly requesting an system interpreter version in check_system_python (#7306)

Needed for #7300

Author: zanieb

.github/workflows/ci.yml

@@ -1326,7 +1326,7 @@ jobs:
         run: echo $(which python)
 
       - name: "Validate global Python install"
-        run: py -3.13 ./scripts/check_system_python.py --uv ./uv.exe
+        run: py -3.13 ./scripts/check_system_python.py --uv ./uv.exe --python 3.13
 
   system-test-choco:
     timeout-minutes: 10

scripts/check_system_python.py

@@ -47,12 +47,18 @@ def install_package(*, uv: str, package: str):
         action="store_true",
         help="Set if the Python installation has an EXTERNALLY-MANAGED marker.",
     )
+    parser.add_argument(
+        "--python",
+        required=False,
+        help="Set if the system Python version must be explicitly specified, e.g., for prereleases.",
+    )
     args = parser.parse_args()
 
     uv: str = os.path.abspath(args.uv) if args.uv else "uv"
     allow_externally_managed = (
         ["--break-system-packages"] if args.externally_managed else []
     )
+    python = ["--python", args.python] if args.python else []
 
     # Create a temporary directory.
     with tempfile.TemporaryDirectory() as temp_dir:
@@ -69,7 +75,8 @@ def install_package(*, uv: str, package: str):
         logging.info("Installing the package `pylint`.")
         subprocess.run(
             [uv, "pip", "install", "pylint", "--system", "--verbose"]
-            + allow_externally_managed,
+            + allow_externally_managed
+            + python,
             cwd=temp_dir,
             check=True,
         )
@@ -94,7 +101,9 @@ def install_package(*, uv: str, package: str):
         # Uninstall the package (`pylint`).
         logging.info("Uninstalling the package `pylint`.")
         subprocess.run(
-            [uv, "pip", "uninstall", "pylint", "--system"] + allow_externally_managed,
+            [uv, "pip", "uninstall", "pylint", "--system"]
+            + allow_externally_managed
+            + python,
             cwd=temp_dir,
             check=True,
         )