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

Doc/whatsnew/3.15.rst

@@ -534,6 +534,14 @@ http.cookies
   (Contributed by Nick Burns and Senthil Kumaran in :gh:`92936`.)
 
 
+idlelib
+-------
+
+*  Add a "Reload from Disk" item to the File menu. This allows discarding
+   unsaved changes and reloading the current version of the file from the disk.
+   (Contributed by Shamil Abdulaev in :gh:`44968`.)
+
+
 inspect
 -------
 

Lib/idlelib/idle_test/test_iomenu.py

@@ -1,17 +1,20 @@
-"Test , coverage 17%."
-
-from idlelib import iomenu
+import builtins
+import os
+import tempfile
 import unittest
+from unittest.mock import patch
+
 from test.support import requires
 from tkinter import Tk
+
+from idlelib import iomenu, util
 from idlelib.editor import EditorWindow
-from idlelib import util
 from idlelib.idle_test.mock_idle import Func
 
 # Fail if either tokenize.open and t.detect_encoding does not exist.
 # These are used in loadfile and encode.
 # Also used in pyshell.MI.execfile and runscript.tabnanny.
-from tokenize import open, detect_encoding
+from tokenize import open as tokenize_open, detect_encoding
 # Remove when we have proper tests that use both.
 
 
@@ -36,6 +39,14 @@ def tearDownClass(cls):
         cls.root.destroy()
         del cls.root
 
+    def _create_tempfile(self, content: str) -> str:
+        fd, filename = tempfile.mkstemp(suffix='.py')
+        os.close(fd)
+        self.addCleanup(os.unlink, filename)
+        with builtins.open(filename, 'w', encoding='utf-8') as f:
+            f.write(content)
+        return filename
+
     def test_init(self):
         self.assertIs(self.io.editwin, self.editwin)
 
@@ -45,17 +56,88 @@ def test_fixnewlines_end(self):
         fix = io.fixnewlines
         text = io.editwin.text
 
-        # Make the editor temporarily look like Shell.
         self.editwin.interp = None
         shelltext = '>>> if 1'
         self.editwin.get_prompt_text = Func(result=shelltext)
-        eq(fix(), shelltext)  # Get... call and '\n' not added.
+        eq(fix(), shelltext)   # Get... call and '\n' not added.
         del self.editwin.interp, self.editwin.get_prompt_text
 
         text.insert(1.0, 'a')
-        eq(fix(), 'a'+io.eol_convention)
+        eq(fix(), 'a' + io.eol_convention)
         eq(text.get('1.0', 'end-1c'), 'a\n')
-        eq(fix(), 'a'+io.eol_convention)
+        eq(fix(), 'a' + io.eol_convention)
+
+    def test_reload_no_file(self):
+        io = self.io
+        io.filename = None
+
+        with patch('idlelib.iomenu.messagebox.showinfo') as mock_showinfo:
+            result = io.reload(None)
+            self.assertEqual(result, "break")
+            mock_showinfo.assert_called_once()
+            args, kwargs = mock_showinfo.call_args
+            self.assertIn("File Not Found", args[0])
+
+    def test_reload_with_file(self):
+        io = self.io
+        text = io.editwin.text
+        original_content = "# Original content\n"
+        modified_content = "# Modified content\n"
+
+        filename = self._create_tempfile(original_content)
+        io.filename = filename
+
+        with patch('idlelib.iomenu.messagebox.showerror') as mock_showerror:
+            io.loadfile(io.filename)
+            self.assertEqual(text.get('1.0', 'end-1c'), original_content)
+
+            with builtins.open(filename, 'w', encoding='utf-8') as f:
+                f.write(modified_content)
+
+            result = io.reload(None)
+
+        mock_showerror.assert_not_called()
+        self.assertEqual(result, "break")
+        self.assertEqual(text.get('1.0', 'end-1c'), modified_content)
+
+    def test_reload_with_unsaved_changes_cancel(self):
+        io = self.io
+        text = io.editwin.text
+        original_content = "# Original content\n"
+        unsaved_content = original_content + "\n# Unsaved change"
+
+        filename = self._create_tempfile(original_content)
+        io.filename = filename
+        io.loadfile(io.filename)
+
+        text.insert('end', "\n# Unsaved change")
+        io.set_saved(False)
+
+        with patch('idlelib.iomenu.messagebox.askokcancel', return_value=False) as mock_ask:
+            result = io.reload(None)
+
+        self.assertEqual(result, "break")
+        self.assertEqual(text.get('1.0', 'end-1c'), unsaved_content)
+        mock_ask.assert_called_once()
+
+    def test_reload_with_unsaved_changes_confirm(self):
+        io = self.io
+        text = io.editwin.text
+        original_content = "# Original content\n"
+
+        filename = self._create_tempfile(original_content)
+        io.filename = filename
+        io.loadfile(io.filename)
+
+        text.insert('end', "\n# Unsaved change")
+        io.set_saved(False)
+
+        with patch('idlelib.iomenu.messagebox.askokcancel', return_value=True) as mock_ask:
+            result = io.reload(None)
+
+        self.assertEqual(result, "break")
+        self.assertEqual(text.get('1.0', 'end-1c'), original_content)
+        mock_ask.assert_called_once()
 
 
 def _extension_in_filetypes(extension):

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 +239,35 @@ 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(
+                "File Not Found",
+                "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"
+
+        # Reload the file
+        self.loadfile(self.filename)
+
+        self.text.focus_set()
+        return "break"
+
     def writefile(self, filename):
         text = self.fixnewlines()
         chars = self.encode(text)

Lib/idlelib/mainmenu.py

@@ -31,6 +31,7 @@
    ('_Save', '<<save-window>>'),
    ('Save _As...', '<<save-window-as-file>>'),
    ('Save Cop_y As...', '<<save-copy-of-window-as-file>>'),
+   ('_Reload from Disk', '<<reload-window>>'),
    None,
    ('Prin_t Window', '<<print-window>>'),
    None,

Misc/NEWS.d/next/IDLE/2025-11-14-20-58-55.gh-issue-44968.rL9dK3.rst

@@ -0,0 +1,3 @@
+Add "Reload from Disk" menu item to IDLE's File menu. This allows users to
+easily reload a file from disk, discarding any unsaved changes in the editor.
+Patch by Shamil Abdulaev.