Fail if an invalid X-option is provided in the command line

Author: pablogsal

Include/internal/pycore_initconfig.h

@@ -82,6 +82,9 @@ PyAPI_FUNC(int) _Py_str_to_int(
 PyAPI_FUNC(const wchar_t*) _Py_get_xoption(
     const PyWideStringList *xoptions,
     const wchar_t *name);
+PyAPI_FUNC(const wchar_t*) _Py_check_xoptions(
+    const PyWideStringList *xoptions,
+    const wchar_t **name);
 PyAPI_FUNC(const char*) _Py_GetEnv(
     int use_environment,
     const char *name);

Lib/test/test_cmd_line.py

@@ -83,8 +83,17 @@ def get_xoptions(*args):
         opts = get_xoptions()
         self.assertEqual(opts, {})
 
-        opts = get_xoptions('-Xa', '-Xb=c,d=e')
-        self.assertEqual(opts, {'a': True, 'b': 'c,d=e'})
+        opts = get_xoptions('-Xno_debug_ranges')
+        self.assertEqual(opts, {'no_debug_ranges': True})
+
+    @unittest.skipIf(interpreter_requires_environment(),
+                     'Cannot run -E tests when PYTHON env vars are required.')
+    def test_unknown_xoptions(self):
+        rc, out, err = assert_python_failure('-X', 'blech')
+        self.assertIn(b'Unknown value for option -X', err)
+        msg = b'Fatal Python error: Unknown value for option -X'
+        self.assertEqual(err.splitlines().count(msg), 1)
+        self.assertEqual(b'', out)
 
     def test_showrefcount(self):
         def run_python(*args):

Python/initconfig.c

@@ -2121,6 +2121,19 @@ _PyConfig_InitImportConfig(PyConfig *config)
     return config_init_import(config, 1);
 }
 
+const wchar_t* known_xoptions[] = {
+    L"faulthandler",
+    L"showrefcount",
+    L"tracemalloc",
+    L"importtime",
+    L"dev",
+    L"utf8",
+    L"pycache_prefix",
+    L"warn_default_encoding",
+    L"no_debug_ranges",
+    L"frozen_modules",
+    NULL,
+};
 
 static PyStatus
 config_read(PyConfig *config, int compute_path_config)
@@ -2136,6 +2149,11 @@ config_read(PyConfig *config, int compute_path_config)
     }
 
     /* -X options */
+    const wchar_t* option = _Py_check_xoptions(&config->xoptions, known_xoptions);
+    if (option != NULL) {
+        return PyStatus_Error("Unknown value for option -X");
+    }
+
     if (config_get_xoption(config, L"showrefcount")) {
         config->show_ref_count = 1;
     }

Python/preconfig.c

@@ -593,6 +593,31 @@ _Py_get_xoption(const PyWideStringList *xoptions, const wchar_t *name)
     return NULL;
 }
 
+const wchar_t*
+_Py_check_xoptions(const PyWideStringList *xoptions, const wchar_t **names)
+{
+    for (Py_ssize_t i=0; i < xoptions->length; i++) {
+        const wchar_t *option = xoptions->items[i];
+        size_t len;
+        wchar_t *sep = wcschr(option, L'=');
+        if (sep != NULL) {
+            len = (sep - option);
+        }
+        else {
+            len = wcslen(option);
+        }
+        int found = 0;
+        for (const wchar_t** name = names; *name != NULL; name++) {
+            if (wcsncmp(option, *name, len) == 0 && (*name)[len] == L'\0') {
+                found = 1;
+            }
+        }
+        if (found == 0) {
+            return option;
+        }
+    }
+    return NULL;
+}
 
 static PyStatus
 preconfig_init_utf8_mode(PyPreConfig *config, const _PyPreCmdline *cmdline)