gh-44968: Add "Reload from Disk" feature to IDLE

Lib/idlelib/iomenu.py

@@ -31,6 +31,7 @@ def __init__(self, editwin):
                                           self.save_as)
         self.__id_savecopy = self.text.bind("<<save-copy-of-window-as-file>>",
                                             self.save_a_copy)
+        self.__id_reload = self.text.bind("<<reload-window>>", self.reload)
         self.fileencoding = 'utf-8'
         self.__id_print = self.text.bind("<<print-window>>", self.print_window)
 
@@ -40,6 +41,7 @@ def close(self):
         self.text.unbind("<<save-window>>", self.__id_save)
         self.text.unbind("<<save-window-as-file>>",self.__id_saveas)
         self.text.unbind("<<save-copy-of-window-as-file>>", self.__id_savecopy)
+        self.text.unbind("<<reload-window>>", self.__id_reload)
         self.text.unbind("<<print-window>>", self.__id_print)
         # Break cycles
         self.editwin = None
@@ -237,6 +239,49 @@ def save_a_copy(self, event):
         self.updaterecentfileslist(filename)
         return "break"
 
+    def reload(self, event):
+        """Reload the file from disk, discarding any unsaved changes.
+
+        If the file has unsaved changes, ask the user to confirm.
+        """
+        if not self.filename:
+            messagebox.showinfo(
+                "No File",
+                "This window has no associated file to reload.",
+                parent=self.text)
+            self.text.focus_set()
+            return "break"
+
+        if not self.get_saved():
+            confirm = messagebox.askokcancel(
+                title="Reload File",
+                message=f"Discard changes to {self.filename}?",
+                default=messagebox.CANCEL,
+                parent=self.text)
+            if not confirm:
+                self.text.focus_set()
+                return "break"
+
+        # Save cursor position
+        insert_pos = self.text.index("insert")
+        yview_pos = self.text.yview()
+
+        # Reload the file
+        if self.loadfile(self.filename):
+            # Try to restore cursor position if the file still has that line
+            try:
+                self.text.mark_set("insert", insert_pos)
+                self.text.see("insert")
+                # Restore vertical scroll position
+                self.text.yview_moveto(yview_pos[0])
+            except Exception:
+                # If position doesn't exist anymore, go to top
+                self.text.mark_set("insert", "1.0")
+                self.text.see("insert")
+
+        self.text.focus_set()
+        return "break"
+
     def writefile(self, filename):
         text = self.fixnewlines()
         chars = self.encode(text)