python · serhiy-storchaka · Dec 25, 2020 · Dec 22, 2020 · Dec 24, 2020 · Dec 24, 2020
diff --git a/Lib/tkinter/__init__.py b/Lib/tkinter/__init__.py
@@ -300,6 +300,31 @@ def _get_default_root(what=None):
    return _default_root


+def _get_temp_root():
+    global _support_default_root
+    if not _support_default_root:
+        raise RuntimeError("No master specified and tkinter is "
+                           "configured to not support default root")
+    root = _default_root
+    if root is None:
+        assert _support_default_root
+        _support_default_root = False
+        root = Tk()
+        _support_default_root = True
+        assert _default_root is None
+        root.withdraw()
+        root._temporary = True
+    return root
+
+
+def _destroy_temp_root(master):
+    if getattr(master, '_temporary', False):
+        try:
+            master.destroy()
+        except TclError:
+            pass
+
+
 def _tkerror(err):
    """Internal function."""
    pass

diff --git a/Lib/tkinter/commondialog.py b/Lib/tkinter/commondialog.py
@@ -10,7 +10,7 @@

 __all__ = ["Dialog"]

-from tkinter import Frame
+from tkinter import Frame, _get_temp_root, _destroy_temp_root


 class Dialog:
@@ -37,22 +37,17 @@ def show(self, **options):

        self._fixoptions()

-        # we need a dummy widget to properly process the options
-        # (at least as long as we use Tkinter 1.63)
-        w = Frame(self.master)
-
+        master = self.master
+        if master is None:
+            master = _get_temp_root()
        try:
-
-            s = w.tk.call(self.command, *w._options(self.options))
-
-            s = self._fixresult(w, s)
-
+            self._test_callback(master)  # The function below is replaced for some tests.
+            s = master.tk.call(self.command, *master._options(self.options))
+            s = self._fixresult(master, s)
        finally:
-
-            try:
-                # get rid of the widget
-                w.destroy()
-            except:
-                pass
+            _destroy_temp_root(master)

        return s
+
+    def _test_callback(self, master):
+        pass
diff --git a/Lib/tkinter/simpledialog.py b/Lib/tkinter/simpledialog.py
@@ -24,7 +24,8 @@
 """

 from tkinter import *
-from tkinter import messagebox, _get_default_root
+from tkinter import _get_temp_root, _destroy_temp_root
+from tkinter import messagebox


 class SimpleDialog:
@@ -100,7 +101,7 @@ def __init__(self, parent, title = None):
        '''
        master = parent
        if master is None:
-            master = _get_default_root('create dialog window')
+            master = _get_temp_root()

        Toplevel.__init__(self, master)

@@ -142,6 +143,7 @@ def destroy(self):
        '''Destroy the window'''
        self.initial_focus = None
        Toplevel.destroy(self)
+        _destroy_temp_root(self.master)

    #
    # construction hooks

diff --git a/Lib/tkinter/test/test_tkinter/test_colorchooser.py b/Lib/tkinter/test/test_tkinter/test_colorchooser.py
@@ -0,0 +1,39 @@
+import unittest
+import tkinter
+from test.support import requires, run_unittest, swap_attr
+from tkinter.test.support import AbstractDefaultRootTest
+from tkinter.commondialog import Dialog
+from tkinter.colorchooser import askcolor
+
+requires('gui')
+
+
+class DefaultRootTest(AbstractDefaultRootTest, unittest.TestCase):
+
+    def test_askcolor(self):
+        def test_callback(dialog, master):
+            nonlocal ismapped
+            master.update()
+            ismapped = master.winfo_ismapped()
+            raise ZeroDivisionError
+
+        with swap_attr(Dialog, '_test_callback', test_callback):
+            ismapped = None
+            self.assertRaises(ZeroDivisionError, askcolor)
+            #askcolor()
+            self.assertEqual(ismapped, False)
+
+            root = tkinter.Tk()
+            ismapped = None
+            self.assertRaises(ZeroDivisionError, askcolor)
+            self.assertEqual(ismapped, True)
+            root.destroy()
+
+            tkinter.NoDefaultRoot()
+            self.assertRaises(RuntimeError, askcolor)
+
+
+tests_gui = (DefaultRootTest,)
+
+if __name__ == "__main__":
+    run_unittest(*tests_gui)
diff --git a/Lib/tkinter/test/test_tkinter/test_messagebox.py b/Lib/tkinter/test/test_tkinter/test_messagebox.py
@@ -0,0 +1,38 @@
+import unittest
+import tkinter
+from test.support import requires, run_unittest, swap_attr
+from tkinter.test.support import AbstractDefaultRootTest
+from tkinter.commondialog import Dialog
+from tkinter.messagebox import showinfo
+
+requires('gui')
+
+
+class DefaultRootTest(AbstractDefaultRootTest, unittest.TestCase):
+
+    def test_showinfo(self):
+        def test_callback(dialog, master):
+            nonlocal ismapped
+            master.update()
+            ismapped = master.winfo_ismapped()
+            raise ZeroDivisionError
+
+        with swap_attr(Dialog, '_test_callback', test_callback):
+            ismapped = None
+            self.assertRaises(ZeroDivisionError, showinfo, "Spam", "Egg Information")
+            self.assertEqual(ismapped, False)
+
+            root = tkinter.Tk()
+            ismapped = None
+            self.assertRaises(ZeroDivisionError, showinfo, "Spam", "Egg Information")
+            self.assertEqual(ismapped, True)
+            root.destroy()
+
+            tkinter.NoDefaultRoot()
+            self.assertRaises(RuntimeError, showinfo, "Spam", "Egg Information")
+
+
+tests_gui = (DefaultRootTest,)
+
+if __name__ == "__main__":
+    run_unittest(*tests_gui)
diff --git a/Lib/tkinter/test/test_tkinter/test_simpledialog.py b/Lib/tkinter/test/test_tkinter/test_simpledialog.py
@@ -10,13 +10,25 @@
 class DefaultRootTest(AbstractDefaultRootTest, unittest.TestCase):

    def test_askinteger(self):
-        self.assertRaises(RuntimeError, askinteger, "Go To Line", "Line number")
-        root = tkinter.Tk()
-        with swap_attr(Dialog, 'wait_window', lambda self, w: w.destroy()):
+        @staticmethod
+        def mock_wait_window(w):
+            nonlocal ismapped
+            ismapped = w.master.winfo_ismapped()
+            w.destroy()
+
+        with swap_attr(Dialog, 'wait_window', mock_wait_window):
+            ismapped = None
+            askinteger("Go To Line", "Line number")
+            self.assertEqual(ismapped, False)
+
+            root = tkinter.Tk()
+            ismapped = None
            askinteger("Go To Line", "Line number")
-        root.destroy()
-        tkinter.NoDefaultRoot()
-        self.assertRaises(RuntimeError, askinteger, "Go To Line", "Line number")
+            self.assertEqual(ismapped, True)
+            root.destroy()
+
+            tkinter.NoDefaultRoot()
+            self.assertRaises(RuntimeError, askinteger, "Go To Line", "Line number")


 tests_gui = (DefaultRootTest,)

diff --git a/Misc/NEWS.d/next/Library/2020-12-22-22-47-22.bpo-42721.I5Ai5L.rst b/Misc/NEWS.d/next/Library/2020-12-22-22-47-22.bpo-42721.I5Ai5L.rst
@@ -0,0 +1,9 @@
+When simple query dialogs (:mod:`tkinter.simpledialog`), message boxes
+(:mod:`tkinter.messagebox`) or color choose dialog
+(:mod:`tkinter.colorchooser`) are created without arguments *master* and
+*parent*, and the default root window is not yet created, and
+:func:`~tkinter.NoDefaultRoot` was not called, a new temporal
+hidden root window will be created automatically. It will not be set as the
+default root window and will be destroyed right after closing the dialog
+window. It will help to use these simple dialog windows in programs which
+do not need other GUI.