std domain: Generate node_id for cmdoptions in the right way

sphinx/domains/std.py

@@ -214,16 +214,25 @@ def handle_signature(self, sig: str, signode: desc_signature) -> str:
     def add_target_and_index(self, firstname: str, sig: str, signode: desc_signature) -> None:
         currprogram = self.env.ref_context.get('std:program')
         for optname in signode.get('allnames', []):
-            targetname = optname.replace('/', '-')
-            if not targetname.startswith('-'):
-                targetname = '-arg-' + targetname
+            prefixes = ['cmdoption']
             if currprogram:
-                targetname = '-' + currprogram + targetname
-            targetname = 'cmdoption' + targetname
-            signode['names'].append(targetname)
+                prefixes.append(currprogram)
+            if not optname.startswith(('-', '/')):
+                prefixes.append('arg')
+            prefix = '-'.join(prefixes)
+            node_id = make_id(self.env, self.state.document, prefix, optname)
+            signode['ids'].append(node_id)
+
+            # Assign old styled node_id not to break old hyperlinks (if possible)
+            # Note: Will be removed in Sphinx-5.0 (RemovedInSphinx50Warning)
+            old_node_id = self.make_old_id(optname)
+            if (old_node_id not in self.state.document.ids and
+                    old_node_id not in signode['ids']):
+                signode['ids'].append(old_node_id)
 
-        domain = cast(StandardDomain, self.env.get_domain('std'))
         self.state.document.note_explicit_target(signode)
+
+        domain = cast(StandardDomain, self.env.get_domain('std'))
         for optname in signode.get('allnames', []):
             domain.add_program_option(currprogram, optname,
                                       self.env.docname, signode['ids'][0])
@@ -237,6 +246,20 @@ def add_target_and_index(self, firstname: str, sig: str, signode: desc_signature
             entry = '; '.join([descr, option])
             self.indexnode['entries'].append(('pair', entry, signode['ids'][0], '', None))
 
+    def make_old_id(self, optname: str) -> str:
+        """Generate old styled node_id for cmdoptions.
+
+        .. note:: Old Styled node_id was used until Sphinx-3.0.
+                  This will be removed in Sphinx-5.0.
+        """
+        currprogram = self.env.ref_context.get('std:program')
+        targetname = optname.replace('/', '-')
+        if not targetname.startswith('-'):
+            targetname = '-arg-' + targetname
+        if currprogram:
+            targetname = '-' + currprogram + targetname
+        return 'cmdoption' + targetname
+
 
 class Program(SphinxDirective):
     """