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Code Issues Projects Releases Packages Wiki Activity Actions 8

Issue #18018: Raise an ImportError if a relative import is attempted

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with no known parent package.

Previously SystemError was raised if the parent package didn't exist
(e.g., __package__ was set to '').
Thanks to Florent Xicluna and Yongzhi Pan for reporting the issue.
This commit is contained in:
Brett Cannon 2016-01-22 16:39:02 -08:00
parent 4b18dd339a
commit 9fa812668f
4 changed files with 20 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

4
Doc/whatsnew/3.6.rst
View file

@ -278,6 +278,10 @@ Changes in the Python API
to ``__spec__.parent`` then :exc:`ImportWarning` is raised. to ``__spec__.parent`` then :exc:`ImportWarning` is raised.
(Contributed by Brett Cannon in :issue:`25791`.) (Contributed by Brett Cannon in :issue:`25791`.)
* When a relative import is performed and no parent package is known, then
:exc:`ImportError` will be raised. Previously, :exc:`SystemError` could be
raised. (Contribute by Brett Cannon in :issue:`18018`.)
Changes in the C API Changes in the C API
-------------------- --------------------

5
Lib/test/test_importlib/import_/test_relative_imports.py
View file

@ -213,6 +213,11 @@ class RelativeImports:
with self.assertRaises(KeyError): with self.assertRaises(KeyError):
self.__import__('sys', level=1) self.__import__('sys', level=1)
def test_relative_import_no_package(self):
with self.assertRaises(ImportError):
self.__import__('a', {'__package__': '', '__spec__': None},
level=1)
(Frozen_RelativeImports, (Frozen_RelativeImports,
Source_RelativeImports Source_RelativeImports

3
Misc/NEWS
View file

@ -10,6 +10,9 @@ Release date: tba
Core and Builtins Core and Builtins
----------------- -----------------
- Issue #18018: Import raises ImportError instead of SystemError if a relative
import is attempted without a known parent package.
- Issue #25843: When compiling code, don't merge constants if they are equal - Issue #25843: When compiling code, don't merge constants if they are equal
but have a different types. For example, ``f1, f2 = lambda: 1, lambda: 1.0`` but have a different types. For example, ``f1, f2 = lambda: 1, lambda: 1.0``
is now correctly compiled to two different functions: ``f1()`` returns ``1`` is now correctly compiled to two different functions: ``f1()`` returns ``1``

11
Python/import.c
View file

@ -1424,7 +1424,7 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *given_globals,
PyErr_SetString(PyExc_TypeError, "package must be a string"); PyErr_SetString(PyExc_TypeError, "package must be a string");
goto error; goto error;
} }
else if (spec != NULL) { else if (spec != NULL && spec != Py_None) {
int equal; int equal;
PyObject *parent = PyObject_GetAttrString(spec, "parent"); PyObject *parent = PyObject_GetAttrString(spec, "parent");
if (parent == NULL) { if (parent == NULL) {
@ -1444,7 +1444,7 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *given_globals,
} }
} }
} }
else if (spec != NULL) { else if (spec != NULL && spec != Py_None) {
package = PyObject_GetAttrString(spec, "parent"); package = PyObject_GetAttrString(spec, "parent");
if (package == NULL) { if (package == NULL) {
goto error; goto error;
@ -1491,7 +1491,12 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *given_globals,
} }
} }
if (PyDict_GetItem(interp->modules, package) == NULL) { if (PyUnicode_CompareWithASCIIString(package, "") == 0) {
PyErr_SetString(PyExc_ImportError,
"attempted relative import with no known parent package");
goto error;
}
else if (PyDict_GetItem(interp->modules, package) == NULL) {
PyErr_Format(PyExc_SystemError, PyErr_Format(PyExc_SystemError,
"Parent module %R not loaded, cannot perform relative " "Parent module %R not loaded, cannot perform relative "
"import", package); "import", package);