gh-71652: Make IDLE help source menu entries unique and sorted

Doc/library/idle.rst

@@ -340,9 +340,14 @@ Python Docs
 Turtle Demo
    Run the turtledemo module with example Python code and turtle drawings.
 
-Additional help sources may be added here with the Configure IDLE dialog under
-the General tab. See the :ref:`Help sources <help-sources>` subsection below
-for more on Help menu choices.
+Additional help sources
+   Menu items for display here are added on the General tab of Options =>
+   Configure IDLE.  Menu entries should be unique (new in 3.9) and will be
+   sorted.  Documents can be located either on the current machine or on the
+   internet.  The allowed file types may depend on the system.  Local file
+   paths are checked when submitted; internet addresses are not.  See the
+   :ref:`Help sources <help-sources>` subsection below for more on Help menu
+   choices.
 
 .. index::
    single: Cut

Lib/idlelib/configdialog.py

@@ -2103,6 +2103,10 @@ def load_general_cfg(self):
 
         # Set additional help sources.
         self.user_helplist = idleConf.GetAllExtraHelpSourcesList()
+        self.set_additional_help_sources()
+
+    def set_additional_help_sources(self):
+        self.user_helplist.sort(key=lambda x: x[0])
         self.helplist.delete(0, 'end')
         for help_item in self.user_helplist:
             self.helplist.insert(END, help_item[0])
@@ -2131,7 +2135,9 @@ def helplist_item_add(self):
         Query for name and location of new help sources and add
         them to the list.
         """
-        help_source = HelpSource(self, 'New Help Source').result
+        used_names = idleConf.GetExtraHelpSourceList('user')
+        help_source = HelpSource(self, 'New Help Source',
+                used_names=[item[0] for item in used_names]).result
         if help_source:
             self.user_helplist.append(help_source)
             self.helplist.insert(END, help_source[0])
@@ -2145,10 +2151,12 @@ def helplist_item_edit(self):
         """
         item_index = self.helplist.index(ANCHOR)
         help_source = self.user_helplist[item_index]
+        used_names = idleConf.GetExtraHelpSourceList('user')
         new_help_source = HelpSource(
                 self, 'Edit Help Source',
                 menuitem=help_source[0],
                 filepath=help_source[1],
+                used_names=[item[0] for item in used_names]
                 ).result
         if new_help_source and new_help_source != help_source:
             self.user_helplist[item_index] = new_help_source
@@ -2171,6 +2179,7 @@ def helplist_item_remove(self):
     def update_help_changes(self):
         "Clear and rebuild the HelpFiles section in changes"
         changes['main']['HelpFiles'] = {}
+        self.set_additional_help_sources()
         for num in range(1, len(self.user_helplist) + 1):
             changes.add_option(
                     'main', 'HelpFiles', str(num),

Lib/idlelib/help.html

@@ -363,9 +363,12 @@ <h3>Help menu (Shell and Editor)<a class="headerlink" href="#help-menu-shell-and
 <dt>Turtle Demo</dt><dd><p>Run the turtledemo module with example Python code and turtle drawings.</p>
 </dd>
 </dl>
-<p>Additional help sources may be added here with the Configure IDLE dialog under
-the General tab. See the <a class="reference internal" href="#help-sources"><span class="std std-ref">Help sources</span></a> subsection below
+<dt>Additional help sources</dt><dd><p>Menu items for display here are added on the General tab of Options => Configure IDLE.
+Menu entries should be unique (new in 3.9) and will be sorted.  Documents can be located either on the current machine or on the internet.
+The allowed file types may depend on the system.  Local file paths are checked when submitted; internet addresses are not.
+See the <a class="reference internal" href="#help-sources"><span class="std std-ref">Help sources</span></a> subsection below
 for more on Help menu choices.</p>
+</dd>
 </div>
 <div class="section" id="context-menus">
 <span id="index-4"></span><h3>Context Menus<a class="headerlink" href="#context-menus" title="Permalink to this headline">¶</a></h3>

Lib/idlelib/idle_test/test_query.py

@@ -217,10 +217,14 @@ class Dummy_HelpSource:
         entry_ok = query.HelpSource.entry_ok
         entry_error = {}
         path_error = {}
+        def __init__(self, used_names={}):
+            self.used_names = used_names
         def item_ok(self):
             return self.name
         def path_ok(self):
             return self.path
+        def showerror(self, message):
+            self.entry_error['text'] = message
 
     def test_entry_ok_helpsource(self):
         dialog = self.Dummy_HelpSource()
@@ -232,6 +236,13 @@ def test_entry_ok_helpsource(self):
                 dialog.name, dialog.path = name, path
                 self.assertEqual(dialog.entry_ok(), result)
 
+    def test_entry_ok_helpsource_duplicate(self):
+        name = 'help1'
+        dialog = self.Dummy_HelpSource({name})
+        dialog.name, dialog.path = name, 'doc.txt'
+        self.assertEqual(dialog.entry_ok(), None)
+        self.assertIn('in use', dialog.entry_error['text'])
+
 
 # 2 CustomRun test classes each test one method.
 

Lib/idlelib/query.py

@@ -314,6 +314,9 @@ def entry_ok(self):
         self.entry_error['text'] = ''
         self.path_error['text'] = ''
         name = self.item_ok()
+        if name in self.used_names:
+            self.showerror('name is already in use.')
+            return None
         path = self.path_ok()
         return None if name is None or path is None else (name, path)
 

Misc/NEWS.d/next/IDLE/2019-11-08-14-29-24.bpo-27465.RUKMNw.rst

@@ -0,0 +1,2 @@
+Additional help sources added to IDLE's help menu are now sorted and must be
+unique.