fix(setup): Existing broken Zope root cookie

[A previous PR fixed the broken Zope root cookie plugin for new
installs](17deb97)
but didn't include an upgrade step for existing Zope instances/ZODBs.  The issue is only
revealed when `IChallengePlugin` is activated for the broken plugins, such as when the
`Products.PlonePAS:root-cookie` profile is installed, and [a `Manager` tries to login
to](#66 (comment)) the
[Zope root ZMI](http://localhost:8080/manage_main).

Add an upgrade step that fixes the issue for existing instances/ZODBs.

src/Products/PlonePAS/profiles.zcml

@@ -20,6 +20,12 @@
     <depends name="memberdata-properties" />
     <depends name="rolemap" />
   </genericsetup:importStep>
+  <genericsetup:upgradeStep
+      title="Fix existing broken Zope root `/acl_users` plugins"
+      profile="Products.PlonePAS:PlonePAS"
+      source="4"
+      destination="5"
+      handler=".upgrades.from4to5_fix_zope_root" />
 
   <genericsetup:registerProfile
       name="root-cookie"

src/Products/PlonePAS/profiles/default/metadata.xml

@@ -1,4 +1,4 @@
 <?xml version="1.0"?>
 <metadata>
-  <version>4</version>
+  <version>5</version>
 </metadata>

src/Products/PlonePAS/upgrades.py

@@ -0,0 +1,59 @@
+"""
+Upgrade steps specific to Plone's use of PAS.
+"""
+
+from Products.PlonePAS.plugins import cookie_handler
+from Products.PluggableAuthService.plugins import CookieAuthHelper
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+def from4to5_fix_zope_root(context):
+    """
+    Fix broken Zope root `/acl_users/` plugins.
+    """
+    root = context.getPhysicalRoot()
+    pas = root.acl_users.manage_addProduct['PluggableAuthService']
+    # Identify which interfaces should be considered PAS plugin interfaces
+    plugin_ifaces = [
+        plugin_type_info["interface"]
+        for plugin_type_info in root.acl_users.plugins.listPluginTypeInfo()
+    ]
+    broken_meta_type = cookie_handler.ExtendedCookieAuthHelper.meta_type
+    broken_plugins = root.acl_users.objectValues(broken_meta_type)
+    for broken_plugin in broken_plugins:
+        # Collect properties from old/broken plugin
+        kwargs = dict(
+            id=broken_plugin.id,
+            title=broken_plugin.title,
+            cookie_name=broken_plugin.cookie_name,
+        )
+        # Which PAS plugin interfaces has this plugin been activated for
+        active_ifaces = [
+            plugin_iface
+            for plugin_iface in plugin_ifaces
+            if plugin_iface.providedBy(broken_plugin)
+            and broken_plugin.id in root.acl_users.plugins.listPluginIds(plugin_iface)
+        ]
+        # Delete the old/broken plugin
+        logger.info(
+            "Deleting broken %r plugin: %r",
+            broken_meta_type,
+            "/".join(broken_plugin.getPhysicalPath()),
+        )
+        root.acl_users.manage_delObjects([broken_plugin.id])
+        # Add the correct plugin
+        logger.info(
+            "Adding working %r plugin: %r",
+            CookieAuthHelper.CookieAuthHelper.meta_type,
+            "/".join(broken_plugin.getPhysicalPath()),
+        )
+        pas.addCookieAuthHelper(**kwargs)
+        # Restore activated plugin interfaces
+        for plugin_iface in active_ifaces:
+            root.acl_users.plugins.activatePlugin(
+                plugin_iface,
+                kwargs["id"],
+            )