gh-103820: IDLE: Do not interpret buttons 4/5 as scrolling on non-X11 (GH-103821)

Also fix test_mousewheel: do not skip a check which was broken due to incorrect
delta on Aqua and XQuartz, and probably not because of `.update_idletasks()`.

Lib/idlelib/editor.py

@@ -166,8 +166,9 @@ class EditorWindow:
             text.bind("<3>",self.right_menu_event)
 
         text.bind('<MouseWheel>', wheel_event)
-        text.bind('<Button-4>', wheel_event)
-        text.bind('<Button-5>', wheel_event)
+        if text._windowingsystem == 'x11':
+            text.bind('<Button-4>', wheel_event)
+            text.bind('<Button-5>', wheel_event)
         text.bind('<Configure>', self.handle_winconfig)
         text.bind("<<cut>>", self.cut)
         text.bind("<<copy>>", self.copy)

Lib/idlelib/idle_test/test_sidebar.py

@@ -690,16 +690,22 @@ class ShellSidebarTest(unittest.TestCase):
         last_lineno = get_end_linenumber(text)
         self.assertIsNotNone(text.dlineinfo(text.index(f'{last_lineno}.0')))
 
-        # Scroll up using the <MouseWheel> event.
-        # The meaning of delta is platform-dependent.
-        delta = -1 if sys.platform == 'darwin' else 120
-        sidebar.canvas.event_generate('<MouseWheel>', x=0, y=0, delta=delta)
-        yield
-        if sys.platform != 'darwin':  # .update_idletasks() does not work.
-            self.assertIsNone(text.dlineinfo(text.index(f'{last_lineno}.0')))
+        # Delta for <MouseWheel>, whose meaning is platform-dependent.
+        delta = 1 if sidebar.canvas._windowingsystem == 'aqua' else 120
 
-        # Scroll back down using the <Button-5> event.
-        sidebar.canvas.event_generate('<Button-5>', x=0, y=0)
+        # Scroll up.
+        if sidebar.canvas._windowingsystem == 'x11':
+            sidebar.canvas.event_generate('<Button-4>', x=0, y=0)
+        else:
+            sidebar.canvas.event_generate('<MouseWheel>', x=0, y=0, delta=delta)
+        yield
+        self.assertIsNone(text.dlineinfo(text.index(f'{last_lineno}.0')))
+
+        # Scroll back down.
+        if sidebar.canvas._windowingsystem == 'x11':
+            sidebar.canvas.event_generate('<Button-5>', x=0, y=0)
+        else:
+            sidebar.canvas.event_generate('<MouseWheel>', x=0, y=0, delta=-delta)
         yield
         self.assertIsNotNone(text.dlineinfo(text.index(f'{last_lineno}.0')))
 

Lib/idlelib/tree.py

@@ -285,8 +285,9 @@ class TreeNode:
         self.label.bind("<1>", self.select_or_edit)
         self.label.bind("<Double-1>", self.flip)
         self.label.bind("<MouseWheel>", lambda e: wheel_event(e, self.canvas))
-        self.label.bind("<Button-4>", lambda e: wheel_event(e, self.canvas))
-        self.label.bind("<Button-5>", lambda e: wheel_event(e, self.canvas))
+        if self.label._windowingsystem == 'x11':
+            self.label.bind("<Button-4>", lambda e: wheel_event(e, self.canvas))
+            self.label.bind("<Button-5>", lambda e: wheel_event(e, self.canvas))
         self.text_id = id
 
     def select_or_edit(self, event=None):
@@ -460,8 +461,9 @@ class ScrolledCanvas:
         self.canvas.bind("<Key-Up>", self.unit_up)
         self.canvas.bind("<Key-Down>", self.unit_down)
         self.canvas.bind("<MouseWheel>", wheel_event)
-        self.canvas.bind("<Button-4>", wheel_event)
-        self.canvas.bind("<Button-5>", wheel_event)
+        if self.canvas._windowingsystem == 'x11':
+            self.canvas.bind("<Button-4>", wheel_event)
+            self.canvas.bind("<Button-5>", wheel_event)
         #if isinstance(master, Toplevel) or isinstance(master, Tk):
         self.canvas.bind("<Alt-Key-2>", self.zoom_height)
         self.canvas.focus_set()

Misc/NEWS.d/next/IDLE/2023-04-25-03-01-23.gh-issue-103820.LCSpza.rst

@@ -0,0 +1,2 @@
+Revise IDLE bindings so that events from mouse button 4/5 on non-X11
+windowing systems (i.e. Win32 and Aqua) are not mistaken for scrolling.