bpo-32857: Raise error when tkinter after_cancel() is called with None. (GH-5701)

(cherry picked from commit 74382a3f175ac285cc924a73fd758e8dc3cc41bb)

Co-authored-by: Cheryl Sabella <cheryl.sabella@gmail.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/Lib/tkinter/__init__.py b/Lib/tkinter/__init__.py
index deea791831..53bad3fa95 100644
--- a/Lib/tkinter/__init__.py
+++ b/Lib/tkinter/__init__.py
@@ -739,6 +739,7 @@ class Misc:
         if not func:
             # I'd rather use time.sleep(ms*0.001)
             self.tk.call('after', ms)
+            return None
         else:
             def callit():
                 try:
@@ -762,11 +763,13 @@ class Misc:
         """Cancel scheduling of function identified with ID.
 
         Identifier returned by after or after_idle must be
-        given as first parameter."""
+        given as first parameter.
+        """
+        if not id:
+            raise ValueError('id must be a valid identifier returned from '
+                             'after or after_idle')
         try:
             data = self.tk.call('after', 'info', id)
-            # In Tk 8.3, splitlist returns: (script, type)
-            # In Tk 8.4, splitlist may return (script, type) or (script,)
             script = self.tk.splitlist(data)[0]
             self.deletecommand(script)
         except TclError: