Fixed a modulefinder crash on certain relative imports.

Lib/modulefinder.py

@@ -309,7 +309,10 @@ class ModuleFinder:
     def _add_badmodule(self, name, caller):
         if name not in self.badmodules:
             self.badmodules[name] = {}
-        self.badmodules[name][caller.__name__] = 1
+        if caller:
+            self.badmodules[name][caller.__name__] = 1
+        else:
+            self.badmodules[name]["-"] = 1
 
     def _safe_import_hook(self, name, caller, fromlist, level=-1):
         # wrapper for self.import_hook() that won't raise ImportError

Lib/test/test_modulefinder.py

@@ -190,6 +190,19 @@ a/b/c/e.py
 a/b/c/f.py
 """]
 
+relative_import_test_3 = [
+    "a.module",
+    ["a", "a.module"],
+    ["a.bar"],
+    [],
+    """\
+a/__init__.py
+                                def foo(): pass
+a/module.py
+                                from . import foo
+                                from . import bar
+"""]
+
 def open_file(path):
     ##print "#", os.path.abspath(path)
     dirname = os.path.dirname(path)
@@ -256,6 +269,9 @@ class ModuleFinderTest(unittest.TestCase):
         def test_relative_imports_2(self):
             self._do_test(relative_import_test_2)
 
+        def test_relative_imports_3(self):
+            self._do_test(relative_import_test_3)
+
 def test_main():
     distutils.log.set_threshold(distutils.log.WARN)
     test_support.run_unittest(ModuleFinderTest)

Misc/NEWS

@@ -30,6 +30,8 @@ Core and Builtins
 Library
 -------
 
+- Fixed a modulefinder crash on certain relative imports.
+
 - Issue #4150: Pdb's "up" command now works for generator frames in post-mortem
   debugging.