CLI: reject module_paths that smell like FS paths

monkeytype/cli.py

@@ -8,6 +8,7 @@
 import difflib
 import importlib
 import inspect
+import os
 import os.path
 import runpy
 import subprocess
@@ -44,6 +45,11 @@ def module_path(path: str) -> Tuple[str, Optional[str]]:
     parts = path.split(':', 1)
     module = parts.pop(0)
     qualname = parts[0] if parts else None
+    if os.sep in module:  # Smells like a path
+        raise argparse.ArgumentTypeError(
+            f'{module} does not look like a valid Python import path'
+        )
+
     return module, qualname
 
 

tests/test_cli.py

@@ -239,3 +239,12 @@ def test_cli_context_manager_activated(capsys, stdout, stderr):
     assert out == "IN SETUP: stub\nIN TEARDOWN: stub\n"
     assert err == ""
     assert ret == 0
+
+
+def test_pathlike_parameter(store_data, capsys):
+    store, db_file = store_data
+    with mock.patch.dict(os.environ, {DefaultConfig.DB_PATH_VAR: db_file.name}):
+        with pytest.raises(SystemExit):
+            cli.main(['stub', 'test/foo.py:bar'], stdout, stderr)
+        out, err = capsys.readouterr()
+        assert "test/foo.py does not look like a valid Python import path" in err