Force environment variables for hg upstream

These won't affect jane's fast-path

bench.py

@@ -70,9 +70,16 @@ def run_repo_command(
     out_path.parent.mkdir(parents=True, exist_ok=True)
     out_path.touch(exist_ok=True)
 
+    # Pass the env to the subcommand of hyperfine, otherwise it won't work
+    env = {
+        "HGMODULEPOLICY": "rust+c",
+        "RUST_LOG": "trace",
+    }
+    env_string = " ".join(f"{k}={v}" for k, v in env.items())
+
     full_cmd = (
-        f"{executable} {cmd} {subprocess_args}"
-        f" > {log_dir / 'stdout'} 2> {log_dir / 'stderr'}"
+        f"{env_string} {executable} {cmd} {subprocess_args} "
+        f"> {log_dir / 'stdout'} 2> {log_dir / 'stderr'}"
     )
     full_cmd = (
         f"hyperfine --warmup 3 --show-output "
@@ -112,14 +119,15 @@ if __name__ == "__main__":
         "--executable",
         dest="executables",
         action="append",
-        default=["hg"],
+        required=True,
         help="Executable(s) to run the tests with",
     )
     (known, others) = parser.parse_known_args()
 
     if others and others[0] != "--":
         print(
-            "abort: use '--' pass arguments to the subprocess", file=sys.stderr
+            "abort: use '--' to pass arguments to the subprocess",
+            file=sys.stderr,
         )
         exit(255)