6.1: Cleanup plone.app.discussion settings when the package is not av…

…ailable.

If the site contains comments, we throw an error and stop the upgrade.
The advice then is to add the `plone.app.discussion` package.

news/211.bugfix

@@ -0,0 +1,4 @@
+6.1: Cleanup ``plone.app.discussion`` settings when the package is not available.
+If the site contains comments, we throw an error and stop the upgrade.
+The advice then is to add the ``plone.app.discussion`` package.
+[maurits]

plone/app/upgrade/v61/configure.zcml

@@ -71,8 +71,8 @@
       >
     <!-- Plone 6.1.0a5 -->
     <gs:upgradeStep
-        title="Miscellaneous"
-        handler="..utils.null_upgrade_step"
+        title="Maybe get rid of plone.app.discussion"
+        handler=".final.maybe_cleanup_discussion"
         />
   </gs:upgradeSteps>
 

plone/app/upgrade/v61/final.py

@@ -1,4 +1,12 @@
+from plone.registry.interfaces import IRegistry
+from zope.component import getUtility
+from Acquisition import aq_parent
+from importlib.metadata import distribution
+from importlib.metadata import PackageNotFoundError
+from plone.app.upgrade.utils import loadMigrationProfile
+from plone.browserlayer.utils import unregister_layer
 from Products.CMFCore.utils import getToolByName
+from zope.component import getSiteManager
 
 import logging
 
@@ -21,3 +29,77 @@ def remove_portal_properties_tool(context):
     # AttributeError: 'PropertiesTool' object has no attribute '__of__'
     portal._delOb("portal_properties")
     logger.info("Removed portal_properties tool.")
+
+
+def maybe_cleanup_discussion(context):
+    """Cleanup some left-overs from plone.app.discussion.
+
+    But only do this when the package is not available.
+    In Plone 6.1, the package was made into a core add-on.
+    Meaning: it no longer gets pulled in by Products.CMFPlone,
+    but only by the Plone package.
+    """
+    # First check if the GS profile was installed.
+    profile_id = "plone.app.discussion:default"
+    if context.getLastVersionForProfile(profile_id) == "unknown":
+        logger.info("%s was not installed, nothing to do.", profile_id)
+        return
+    try:
+        distribution("plone.app.discussion")
+        logger.info("The plone.app.discussion package is available, so we do nothing.")
+        return
+    except PackageNotFoundError:
+        logger.info("plone.app.discussion package not found, will cleanup.")
+
+    # First check if there are any actual discussion items in the site.
+    catalog = getToolByName(context, "portal_catalog")
+    brains = catalog.unrestrictedSearchResults(portal_type="Discussion Item")
+    total = len(brains)
+    if total:
+        raise ValueError(
+            f"{total} Discussion Items (comments) were found in the site, but "
+            "plone.app.discussion is missing.\nThis package is optional since "
+            "Plone 6.1.\nPlease add plone.app.discussion to your Plone installation "
+            "if you want to keep using them."
+        )
+
+    # First apply a profile.  This is mostly a copy of the uninstall profile
+    # of plone.app.discussion.
+    loadMigrationProfile(context, "profile-plone.app.upgrade.v61:uninstall-discussion")
+
+    # The registry keys were registered via the IDiscussionSettings interface
+    # which no longer exists, so we remove them one by one.
+    registry = getUtility(IRegistry)
+    records = registry.records
+    to_remove = [
+        key
+        for key in records.keys()
+        if "plone.app.discussion.interfaces.IDiscussionSettings" in key
+    ]
+    for key in to_remove:
+        del records[key]
+    logger.info("Removed all IDiscussionSettings registry records.")
+
+    # Gather the FTIs that have the plone.allowdiscussion behavior.
+    # It can appear with the name or the interface identifier.
+    portal_types = getToolByName(context, "portal_types")
+    old_behaviors = {
+        "plone.allowdiscussion",
+        "plone.app.dexterity.behaviors.discussion.IAllowDiscussion",
+    }
+    ftis_to_fix = (
+        fti
+        for fti in portal_types.objectValues("Dexterity FTI")
+        if set(fti.behaviors) & old_behaviors
+    )
+    for fti in ftis_to_fix:
+        # Remove the behavior.  Remember this is a tuple.
+        behaviors = [
+            behavior for behavior in fti.behaviors if behavior not in old_behaviors
+        ]
+        # Set the updated behaviors
+        fti.behaviors = tuple(behaviors)
+        logger.info("Removed plone.allowdiscussion behavior from %s", fti)
+
+    # Mark GS profile as not installed/activated.
+    context.unsetLastVersionForProfile(profile_id)

plone/app/upgrade/v61/profiles.zcml

@@ -11,4 +11,13 @@
       provides="Products.GenericSetup.interfaces.EXTENSION"
       />
 
+  <!-- This is a copy of plone.app.discussion/profiles/uninstall. -->
+  <genericsetup:registerProfile
+      name="uninstall-discussion"
+      title="Uninstall plone.app.discussion"
+      directory="profiles/uninstall-discussion"
+      for="plone.base.interfaces.IMigratingPloneSiteRoot"
+      provides="Products.GenericSetup.interfaces.EXTENSION"
+      />
+
 </configure>

plone/app/upgrade/v61/profiles/uninstall-discussion/actions.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object xmlns:i18n="http://xml.zope.org/namespaces/i18n"
+        name="portal_actions"
+>
+  <object meta_type="CMF Action Category"
+          name="user"
+  >
+    <object meta_type="CMF Action"
+            name="review-comments"
+            remove="true"
+    />
+  </object>
+</object>

plone/app/upgrade/v61/profiles/uninstall-discussion/browserlayer.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layers>
+  <layer name="plone.app.discussion"
+         remove="true"
+  />
+</layers>

plone/app/upgrade/v61/profiles/uninstall-discussion/catalog.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object name="portal_catalog">
+
+  <index meta_type="FieldIndex"
+         name="total_comments"
+         remove="true"
+  />
+  <index meta_type="KeywordIndex"
+         name="commentators"
+         remove="true"
+  />
+  <column remove="true"
+          value="total_comments"
+  />
+  <column remove="true"
+          value="last_comment_date"
+  />
+  <column remove="true"
+          value="commentators"
+  />
+  <column remove="true"
+          value="in_response_to"
+  />
+  <column remove="true"
+          value="author_name"
+  />
+
+</object>

plone/app/upgrade/v61/profiles/uninstall-discussion/controlpanel.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object xmlns:i18n="http://xml.zope.org/namespaces/i18n"
+        name="portal_controlpanel"
+        purge="False"
+        i18n:domain="plone"
+>
+
+  <configlet action_id="discussion"
+             appId="plone.app.discussion"
+             category="plone-content"
+             remove="true"
+  />
+
+</object>

plone/app/upgrade/v61/profiles/uninstall-discussion/registry.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<registry>
+  <!-- This would give ModuleNotFoundError: No module named 'plone.app.discussion'
+       So we do this in Python code in maybe_cleanup_discussion. -->
+  <!-- <records interface="plone.app.discussion.interfaces.IDiscussionSettings"
+           remove="true"
+  /> -->
+</registry>

plone/app/upgrade/v61/profiles/uninstall-discussion/types.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object meta_type="CMF Types Tool"
+        name="portal_types"
+>
+  <object meta_type="Factory-based Type Information"
+          name="Discussion Item"
+	  remove="True"
+  />
+</object>

plone/app/upgrade/v61/profiles/uninstall-discussion/workflows.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object meta_type="Plone Workflow Tool"
+        name="portal_workflow"
+>
+  <object meta_type="Workflow"
+          name="comment_review_workflow"
+          remove="True"
+  />
+  <object meta_type="Workflow"
+          name="comment_one_state_workflow"
+          remove="True"
+  />
+</object>