Close #15386: There was a loophole that meant importlib.machinery and imp would sometimes reference an uninitialised copy of importlib._bootstrap
diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index 28655f0..3c8359a 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -165,6 +165,9 @@
option '-uall,-gui'.
"""
+# We import importlib *ASAP* in order to test #15386
+import importlib
+
import builtins
import faulthandler
import getopt
diff --git a/Lib/test/test_import.py b/Lib/test/test_import.py
index 89ec8dc..51b52c7 100644
--- a/Lib/test/test_import.py
+++ b/Lib/test/test_import.py
@@ -1,8 +1,9 @@
+# We import importlib *ASAP* in order to test #15386
+import importlib
import builtins
import imp
from importlib.test.import_ import test_suite as importlib_import_test_suite
from importlib.test.import_ import util as importlib_util
-import importlib
import marshal
import os
import platform
@@ -777,6 +778,15 @@
self.assertEqual(mod.__package__, 'importlib')
self.assertTrue(mod.__file__.endswith('_bootstrap.py'), mod.__file__)
+ def test_there_can_be_only_one(self):
+ # Issue #15386 revealed a tricky loophole in the bootstrapping
+ # This test is technically redundant, since the bug caused importing
+ # this test module to crash completely, but it helps prove the point
+ from importlib import machinery
+ mod = sys.modules['_frozen_importlib']
+ self.assertIs(machinery.FileFinder, mod.FileFinder)
+ self.assertIs(imp.new_module, mod.new_module)
+
class ImportTracebackTests(unittest.TestCase):