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gh-95754: Better error when script shadows a standard library or third party module (#113769)

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Shantanu 2024-04-22 18:24:21 -07:00 • committed by GitHub
parent c9829eec08
commit 8e86579cae
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8 changed files with 458 additions and 55 deletions
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248
Objects/moduleobject.c
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@ -3,6 +3,7 @@
#include "Python.h"
#include "pycore_call.h" // _PyObject_CallNoArgs()
#include "pycore_fileutils.h" // _Py_wgetcwd
#include "pycore_interp.h" // PyInterpreterState.importlib
#include "pycore_modsupport.h" // _PyModule_CreateInitialized()
#include "pycore_moduleobject.h" // _PyModule_GetDef()
@ -10,6 +11,7 @@
#include "pycore_pyerrors.h" // _PyErr_FormatFromCause()
#include "pycore_pystate.h" // _PyInterpreterState_GET()
#include "osdefs.h" // MAXPATHLEN
static PyMemberDef module_members[] = {
@ -785,11 +787,104 @@ _PyModuleSpec_IsUninitializedSubmodule(PyObject *spec, PyObject *name)
return rc;
}
static int
_get_file_origin_from_spec(PyObject *spec, PyObject **p_origin)
{
PyObject *has_location = NULL;
int rc = PyObject_GetOptionalAttr(spec, &_Py_ID(has_location), &has_location);
if (rc <= 0) {
return rc;
}
// If origin is not a location, or doesn't exist, or is not a str), we could consider falling
// back to module.__file__. But the cases in which module.__file__ is not __spec__.origin
// are cases in which we probably shouldn't be guessing.
rc = PyObject_IsTrue(has_location);
Py_DECREF(has_location);
if (rc <= 0) {
return rc;
}
// has_location is true, so origin is a location
PyObject *origin = NULL;
rc = PyObject_GetOptionalAttr(spec, &_Py_ID(origin), &origin);
if (rc <= 0) {
return rc;
}
assert(origin != NULL);
if (!PyUnicode_Check(origin)) {
Py_DECREF(origin);
return 0;
}
*p_origin = origin;
return 1;
}
static int
_is_module_possibly_shadowing(PyObject *origin)
{
// origin must be a unicode subtype
// Returns 1 if the module at origin could be shadowing a module of the
// same name later in the module search path. The condition we check is basically:
// root = os.path.dirname(origin.removesuffix(os.sep + "__init__.py"))
// return not sys.flags.safe_path and root == (sys.path[0] or os.getcwd())
// Returns 0 otherwise (or if we aren't sure)
// Returns -1 if an error occurred that should be propagated
if (origin == NULL) {
return 0;
}
// not sys.flags.safe_path
const PyConfig *config = _Py_GetConfig();
if (config->safe_path) {
return 0;
}
// root = os.path.dirname(origin.removesuffix(os.sep + "__init__.py"))
wchar_t root[MAXPATHLEN + 1];
Py_ssize_t size = PyUnicode_AsWideChar(origin, root, MAXPATHLEN);
if (size < 0) {
return -1;
}
assert(size <= MAXPATHLEN);
root[size] = L'\0';
wchar_t *sep = wcsrchr(root, SEP);
if (sep == NULL) {
return 0;
}
// If it's a package then we need to look one directory further up
if (wcscmp(sep + 1, L"__init__.py") == 0) {
*sep = L'\0';
sep = wcsrchr(root, SEP);
if (sep == NULL) {
return 0;
}
}
*sep = L'\0';
// sys.path[0] or os.getcwd()
wchar_t *sys_path_0 = config->sys_path_0;
if (!sys_path_0) {
return 0;
}
wchar_t sys_path_0_buf[MAXPATHLEN];
if (sys_path_0[0] == L'\0') {
// if sys.path[0] == "", treat it as if it were the current directory
if (!_Py_wgetcwd(sys_path_0_buf, MAXPATHLEN)) {
return -1;
}
sys_path_0 = sys_path_0_buf;
}
int result = wcscmp(sys_path_0, root) == 0;
return result;
}
PyObject*
_Py_module_getattro_impl(PyModuleObject *m, PyObject *name, int suppress)
{
// When suppress=1, this function suppresses AttributeError.
PyObject *attr, *mod_name, *getattr, *origin;
PyObject *attr, *mod_name, *getattr;
attr = _PyObject_GenericGetAttrWithDict((PyObject *)m, name, NULL, suppress);
if (attr) {
return attr;
@ -820,68 +915,111 @@ _Py_module_getattro_impl(PyModuleObject *m, PyObject *name, int suppress)
Py_DECREF(getattr);
return result;
}
// The attribute was not found. We make a best effort attempt at a useful error message,
// but only if we're not suppressing AttributeError.
if (suppress == 1) {
return NULL;
}
if (PyDict_GetItemRef(m->md_dict, &_Py_ID(__name__), &mod_name) < 0) {
return NULL;
}
if (mod_name && PyUnicode_Check(mod_name)) {
PyObject *spec;
if (PyDict_GetItemRef(m->md_dict, &_Py_ID(__spec__), &spec) < 0) {
Py_DECREF(mod_name);
return NULL;
}
if (suppress != 1) {
int rc = _PyModuleSpec_IsInitializing(spec);
if (rc > 0) {
int valid_spec = PyObject_GetOptionalAttr(spec, &_Py_ID(origin), &origin);
if (valid_spec == -1) {
Py_XDECREF(spec);
Py_DECREF(mod_name);
return NULL;
}
if (valid_spec == 1 && !PyUnicode_Check(origin)) {
valid_spec = 0;
Py_DECREF(origin);
}
if (valid_spec == 1) {
PyErr_Format(PyExc_AttributeError,
"partially initialized "
"module '%U' from '%U' has no attribute '%U' "
"(most likely due to a circular import)",
mod_name, origin, name);
Py_DECREF(origin);
}
else {
PyErr_Format(PyExc_AttributeError,
"partially initialized "
"module '%U' has no attribute '%U' "
"(most likely due to a circular import)",
mod_name, name);
}
}
else if (rc == 0) {
rc = _PyModuleSpec_IsUninitializedSubmodule(spec, name);
if (rc > 0) {
PyErr_Format(PyExc_AttributeError,
"cannot access submodule '%U' of module '%U' "
"(most likely due to a circular import)",
name, mod_name);
}
else if (rc == 0) {
PyErr_Format(PyExc_AttributeError,
"module '%U' has no attribute '%U'",
mod_name, name);
}
}
}
Py_XDECREF(spec);
if (!mod_name || !PyUnicode_Check(mod_name)) {
Py_XDECREF(mod_name);
PyErr_Format(PyExc_AttributeError,
"module has no attribute '%U'", name);
return NULL;
}
PyObject *spec;
if (PyDict_GetItemRef(m->md_dict, &_Py_ID(__spec__), &spec) < 0) {
Py_DECREF(mod_name);
return NULL;
}
Py_XDECREF(mod_name);
if (suppress != 1) {
if (spec == NULL) {
PyErr_Format(PyExc_AttributeError,
"module has no attribute '%U'", name);
"module '%U' has no attribute '%U'",
mod_name, name);
Py_DECREF(mod_name);
return NULL;
}
PyObject *origin = NULL;
if (_get_file_origin_from_spec(spec, &origin) < 0) {
goto done;
}
int is_possibly_shadowing = _is_module_possibly_shadowing(origin);
if (is_possibly_shadowing < 0) {
goto done;
}
int is_possibly_shadowing_stdlib = 0;
if (is_possibly_shadowing) {
PyObject *stdlib_modules = PySys_GetObject("stdlib_module_names");
if (stdlib_modules && PyAnySet_Check(stdlib_modules)) {
is_possibly_shadowing_stdlib = PySet_Contains(stdlib_modules, mod_name);
if (is_possibly_shadowing_stdlib < 0) {
goto done;
}
}
}
if (is_possibly_shadowing_stdlib) {
assert(origin);
PyErr_Format(PyExc_AttributeError,
"module '%U' has no attribute '%U' "
"(consider renaming '%U' since it has the same "
"name as the standard library module named '%U' "
"and the import system gives it precedence)",
mod_name, name, origin, mod_name);
}
else {
int rc = _PyModuleSpec_IsInitializing(spec);
if (rc > 0) {
if (is_possibly_shadowing) {
assert(origin);
// For third-party modules, only mention the possibility of
// shadowing if the module is being initialized.
PyErr_Format(PyExc_AttributeError,
"module '%U' has no attribute '%U' "
"(consider renaming '%U' if it has the same name "
"as a third-party module you intended to import)",
mod_name, name, origin);
}
else if (origin) {
PyErr_Format(PyExc_AttributeError,
"partially initialized "
"module '%U' from '%U' has no attribute '%U' "
"(most likely due to a circular import)",
mod_name, origin, name);
}
else {
PyErr_Format(PyExc_AttributeError,
"partially initialized "
"module '%U' has no attribute '%U' "
"(most likely due to a circular import)",
mod_name, name);
}
}
else if (rc == 0) {
rc = _PyModuleSpec_IsUninitializedSubmodule(spec, name);
if (rc > 0) {
PyErr_Format(PyExc_AttributeError,
"cannot access submodule '%U' of module '%U' "
"(most likely due to a circular import)",
name, mod_name);
}
else if (rc == 0) {
PyErr_Format(PyExc_AttributeError,
"module '%U' has no attribute '%U'",
mod_name, name);
}
}
}
done:
Py_XDECREF(origin);
Py_DECREF(spec);
Py_DECREF(mod_name);
return NULL;
}