Merge with 3.4

Lib/idlelib/GrepDialog.py

 import os
 import fnmatch
+import re  # for htest
 import sys
-from tkinter import *
+from tkinter import StringVar, BooleanVar, Checkbutton  # for GrepDialog
+from tkinter import Tk, Text, Button, SEL, END  # for htest
 from idlelib import SearchEngine
+import itertools
 from idlelib.SearchDialogBase import SearchDialogBase
+# Importing OutputWindow fails due to import loop
+# EditorWindow -> GrepDialop -> OutputWindow -> EditorWindow
 
 def grep(text, io=None, flist=None):
     root = text._root()
@@ -63,7 +68,7 @@ class GrepDialog(SearchDialogBase):
         if not path:
             self.top.bell()
             return
-        from idlelib.OutputWindow import OutputWindow
+        from idlelib.OutputWindow import OutputWindow  # leave here!
         save = sys.stdout
         try:
             sys.stdout = OutputWindow(self.flist)
@@ -79,6 +84,7 @@ class GrepDialog(SearchDialogBase):
         pat = self.engine.getpat()
         print("Searching %r in %s ..." % (pat, path))
         hits = 0
+        try:
             for fn in list:
                 try:
                     with open(fn, errors='replace') as f:
@@ -94,6 +100,10 @@ class GrepDialog(SearchDialogBase):
             print(("Hits found: %s\n"
                   "(Hint: right-click to open locations.)"
                   % hits) if hits else "No hits.")
+        except AttributeError:
+            # Tk window has been closed, OutputWindow.text = None,
+            # so in OW.write, OW.text.insert fails.
+            pass
 
     def findfiles(self, dir, base, rec):
         try:
@@ -120,7 +130,8 @@ class GrepDialog(SearchDialogBase):
             self.top.grab_release()
             self.top.withdraw()
 
-def _grep_dialog(parent):
+
+def _grep_dialog(parent):  # for htest
     from idlelib.PyShell import PyShellFileList
     root = Tk()
     root.title("Test GrepDialog")
@@ -141,8 +152,6 @@ def _grep_dialog(parent):
     root.mainloop()
 
 if __name__ == "__main__":
-    # A human test is a bit tricky since EditorWindow() imports this module.
-    # Hence Idle must be restarted after editing this file for a live test.
     import unittest
     unittest.main('idlelib.idle_test.test_grep', verbosity=2, exit=False)