bpo-29546: Set 'path' on ImportError for from ... import ... (GH-91)

Author: Carreau

Lib/test/test_import/__init__.py

@@ -80,6 +80,25 @@ def test_from_import_missing_attr_raises_ImportError(self):
         with self.assertRaises(ImportError):
             from importlib import something_that_should_not_exist_anywhere
 
+    def test_from_import_missing_attr_has_name_and_path(self):
+        with self.assertRaises(ImportError) as cm:
+            from os import i_dont_exist
+        self.assertEqual(cm.exception.name, 'os')
+        self.assertEqual(cm.exception.path, os.__file__)
+
+    def test_from_import_missing_attr_has_name(self):
+        with self.assertRaises(ImportError) as cm:
+            # _warning has no path as it's a built-in module.
+            from _warning import i_dont_exist
+        self.assertEqual(cm.exception.name, '_warning')
+        self.assertIsNone(cm.exception.path)
+
+    def test_from_import_missing_attr_path_is_canonical(self):
+        with self.assertRaises(ImportError) as cm:
+            from os.path import i_dont_exist
+        self.assertIn(cm.exception.name, {'posixpath', 'ntpath'})
+        self.assertIsNotNone(cm.exception)
+
     def test_case_sensitivity(self):
         # Brief digression to test that import is case-sensitive:  if we got
         # this far, we know for sure that "random" exists.

Misc/NEWS

@@ -12,6 +12,8 @@ Core and Builtins
 
 - bpo-29438: Fixed use-after-free problem in key sharing dict.
 
+- bpo-29546: Set the 'path' and 'name' attribute on ImportError for ``from ... import ...``.
+
 - Issue #29319: Prevent RunMainFromImporter overwriting sys.path[0].
 
 - Issue #29337: Fixed possible BytesWarning when compare the code objects.

Python/ceval.c

@@ -4995,7 +4995,7 @@ import_from(PyObject *v, PyObject *name)
 {
     PyObject *x;
     _Py_IDENTIFIER(__name__);
-    PyObject *fullmodname, *pkgname;
+    PyObject *fullmodname, *pkgname, *pkgpath;
 
     x = PyObject_GetAttr(v, name);
     if (x != NULL || !PyErr_ExceptionMatches(PyExc_AttributeError))
@@ -5021,7 +5021,15 @@ import_from(PyObject *v, PyObject *name)
     Py_INCREF(x);
     return x;
  error:
-    PyErr_Format(PyExc_ImportError, "cannot import name %R", name);
+    pkgpath = PyModule_GetFilenameObject(v);
+
+    if (pkgpath == NULL || !PyUnicode_Check(pkgpath)) {
+        PyErr_Clear();
+        PyErr_SetImportError(PyUnicode_FromFormat("cannot import name %R", name), pkgname, NULL);
+    } else {
+        PyErr_SetImportError(PyUnicode_FromFormat("cannot import name %R", name), pkgname, pkgpath);
+    }
+
     return NULL;
 }