gh-55646: Name the action and suggest reconfiguring in the warning

Author: serhiy-storchaka

Lib/idlelib/idle_test/test_multicall.py

@@ -58,7 +58,9 @@ def test_invalid_triplet_binding(self):
         with captured_stderr() as stderr:
             mctext.event_add('<<test-bad>>', '<Control-Key-up>')  # Must not raise.
             mctext.bind('<<test-bad>>', lambda e: None)  # Must not raise.
-        self.assertIn('invalid key binding', stderr.getvalue())
+        warning = stderr.getvalue()
+        self.assertIn('invalid key binding', warning)
+        self.assertIn('test-bad', warning)  # The offending action is named.
 
     def test_invalid_nontriplet_binding(self):
         # gh-55646: '<Foo-Key-Up>' has no valid modifier, so MultiCall does not
@@ -67,7 +69,10 @@ def test_invalid_nontriplet_binding(self):
         with captured_stderr() as stderr:
             mctext.event_add('<<test-bad>>', '<Foo-Key-Up>')  # Must not raise.
             mctext.bind('<<test-bad>>', lambda e: None)  # Must not raise.
-        self.assertIn('invalid key binding', stderr.getvalue())
+        warning = stderr.getvalue()
+        self.assertIn('invalid key binding', warning)
+        self.assertIn('test-bad', warning)  # The offending action is named.
+
     def test_event_delete_unbound_sequence(self):
         # gh-89360: deleting a sequence that was not added to a virtual
         # event is ignored instead of raising ValueError.

Lib/idlelib/multicall.py

@@ -311,9 +311,13 @@ def _triplet_to_sequence(triplet):
         return '<'+_state_names[triplet[0]]+_types[triplet[1]][0]+'>'
 
 
-def _warn_bad_binding(sequence, err):
+def _warn_bad_binding(virtual, sequence, err):
     # gh-55646: warn instead of crashing on an invalid key binding.
-    print(f'Warning: ignoring invalid key binding {sequence!r}: {err}',
+    action = virtual[2:-2] if virtual[:2] == '<<' and virtual[-2:] == '>>' \
+             else virtual
+    print(f'Warning: ignoring invalid key binding {sequence!r} '
+          f'for {action!r}: {err}. '
+          f'Please reconfigure it in the IDLE Settings dialog.',
           file=sys.stderr)
 
 
@@ -355,7 +359,8 @@ def bind(self, sequence=None, func=None, add=None):
                             try:
                                 self.__binders[triplet[1]].bind(triplet, func)
                             except tkinter.TclError as err:
-                                _warn_bad_binding(_triplet_to_sequence(triplet),
+                                _warn_bad_binding(sequence,
+                                                  _triplet_to_sequence(triplet),
                                                   err)
                                 bad.append(triplet)
                         for triplet in bad:  # Drop the invalid sequences.
@@ -389,14 +394,15 @@ def event_add(self, virtual, *sequences):
                     try:
                         widget.event_add(self, virtual, seq)
                     except tkinter.TclError as err:
-                        _warn_bad_binding(seq, err)
+                        _warn_bad_binding(virtual, seq, err)
                         continue  # Drop the invalid sequence.
                 else:
                     if func is not None:
                         try:
                             self.__binders[triplet[1]].bind(triplet, func)
                         except tkinter.TclError as err:
-                            _warn_bad_binding(_triplet_to_sequence(triplet), err)
+                            _warn_bad_binding(virtual,
+                                              _triplet_to_sequence(triplet), err)
                             continue  # Drop the invalid sequence.
                     triplets.append(triplet)