raise an ImportError (rather than fatal) when __import__ is not found in…

raise an ImportError (rather than fatal) when __import__ is not found in __builtins__ (closes #17867)

Lib/test/test_import.py

@@ -324,6 +324,13 @@ class ImportTests(unittest.TestCase):
         except ImportError:
             self.fail("fromlist must allow bogus names")
 
+    @cpython_only
+    def test_delete_builtins_import(self):
+        args = ["-c", "del __builtins__.__import__; import os"]
+        popen = script_helper.spawn_python(*args)
+        stdout, stderr = popen.communicate()
+        self.assertIn(b"ImportError", stdout)
+
 
 @skip_if_dont_write_bytecode
 class FilePermissionTests(unittest.TestCase):

Misc/NEWS

@@ -12,6 +12,8 @@ What's New in Python 3.3.2?
 Core and Builtins
 -----------------
 
+- Issue #17867: Raise an ImportError if __import__ is not found in __builtins__.
+
 - Issue #17857: Prevent build failures with pre-3.5.0 versions of sqlite3,
   such as was shipped with Centos 5 and Mac OS X 10.4.
 

Python/import.c

@@ -1389,7 +1389,8 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *given_globals,
     if (builtins_import == NULL) {
         builtins_import = _PyDict_GetItemId(interp->builtins, &PyId___import__);
         if (builtins_import == NULL) {
-            Py_FatalError("__import__ missing");
+            PyErr_SetString(PyExc_ImportError, "__import__ not found");
+            goto error_with_unlock;
         }
     }
     Py_INCREF(builtins_import);