Update dirty tracking to support Mongoid 8.0+

It appears Mongoid 8.0+ slightly [changed dirty tracking] behavior to
more closely match Active Model/Record, however they haven't yet
introduced the [new methods] that match the latest API, that seems to be
coming on Mongoid 8.1 only.

The changes here try to accommodate for that by determining which
"attribute_changed?" method to call depending on whether the
"*_previously_*" version exists. Newer versions of AR (5.1+) will
continue to use the new API / methods, whereas previous versions and
Mongoid 8.0+ will use these tweaked versions. No behavior should change
for AR, but it will hopefully support Mongoid 8.0+ now.

[changed dirty tracking]
mongodb/mongoid#5092

[new methods]
mongodb/mongoid#5440

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 * enhancements
   * Removed deprecations warning output for `Devise::Models::Authenticatable::BLACKLIST_FOR_SERIALIZATION` (@soartec-lab)
+  * Reenable Mongoid test suite across all Rails 6+ versions, to ensure we continue supporting it. Changes to dirty tracking to support Mongoid 8.0+. [#5568](https://github.com/heartcombo/devise/pull/5568)
 
 Please check [4-stable](https://github.com/heartcombo/devise/blob/4-stable/CHANGELOG.md)
 for previous changes.

gemfiles/Gemfile-rails-main

@@ -25,5 +25,6 @@ platforms :ruby do
 end
 
 group :mongoid do
-  gem "mongoid", "~> 7.5"
+  # gem "mongoid", "~> 8.1"
+  gem "mongoid", github: "mongodb/mongoid", branch: "8.1-stable"
 end

lib/devise/orm.rb

@@ -5,10 +5,14 @@ def self.active_record?(model)
     end
 
     def self.included(model)
-      model.include DirtyTrackingMethods
+      if Devise::Orm.active_record?(model)
+        model.include DirtyTrackingActiveRecordMethods
+      else
+        model.include DirtyTrackingMongoidMethods
+      end
     end
 
-    module DirtyTrackingMethods
+    module DirtyTrackingActiveRecordMethods
       def devise_email_before_last_save
         email_before_last_save
       end
@@ -33,5 +37,31 @@ def devise_respond_to_and_will_save_change_to_attribute?(attribute)
         respond_to?("will_save_change_to_#{attribute}?") && send("will_save_change_to_#{attribute}?")
       end
     end
+
+    module DirtyTrackingMongoidMethods
+      def devise_email_before_last_save
+        respond_to?(:email_previously_was) ? email_previously_was : email_was
+      end
+
+      def devise_email_in_database
+        email_was
+      end
+
+      def devise_saved_change_to_email?
+        respond_to?(:email_previously_changed?) ? email_previously_changed? : email_changed?
+      end
+
+      def devise_saved_change_to_encrypted_password?
+        respond_to?(:encrypted_password_previously_changed?) ? encrypted_password_previously_changed? : encrypted_password_changed?
+      end
+
+      def devise_will_save_change_to_email?
+        email_changed?
+      end
+
+      def devise_respond_to_and_will_save_change_to_attribute?(attribute)
+        respond_to?("#{attribute}_changed?") && send("#{attribute}_changed?")
+      end
+    end
   end
 end