fix: nox.session.run-ing commands with pathlib.Path arguments (#649)

* fix: nox.session.run-ing commands with pathlib.Path arguments

Previously this should have worked in theory, but the string
which is logged for debugging calls shlex.quote, which was
blowing up trying to quote the pathlib.Path.

I'm slightly surprised shlex.quote doesn't support pathlib.Path
objects (yet?) but for now here this just falls back to a cruder
representation when quoting fails.

* Use os.fspath instead.

nox/command.py

@@ -71,8 +71,7 @@ def _clean_env(env: dict[str, str] | None) -> dict[str, str] | None:
 
 
 def _shlex_join(args: Sequence[str]) -> str:
-    # shlex.join() was added in Python 3.8
-    return " ".join(shlex.quote(arg) for arg in args)
+    return " ".join(shlex.quote(os.fspath(arg)) for arg in args)
 
 
 def run(

tests/test_command.py

@@ -22,6 +22,7 @@
 import subprocess
 import sys
 import time
+from pathlib import Path
 from textwrap import dedent
 from unittest import mock
 
@@ -112,6 +113,19 @@ def test_run_verbosity_failed_command(capsys, caplog):
     assert not logs
 
 
+@pytest.mark.skipif(
+    platform.system() == "Windows",
+    reason="See https://github.com/python/cpython/issues/85815",
+)
+def test_run_non_str():
+    result = nox.command.run(
+        [Path(PYTHON), "-c", "import sys; print(sys.argv)", Path(PYTHON)],
+        silent=True,
+    )
+
+    assert PYTHON in result
+
+
 def test_run_env_unicode():
     result = nox.command.run(
         [PYTHON, "-c", 'import os; print(os.environ["SIGIL"])'],