Update docs

CHANGELOG.txt

@@ -8,6 +8,7 @@ Changelog
  * Convert various pages in the documentation to Markdown (Daniel Kirkham)
  * Add `base_url_path` to `ModelAdmin` so that the default URL structure of app_label/model_name can be overridden (Vu Pham, Khanh Hoang)
  * Add `full_url` to the API output of `ImageRenditionField` (Paarth Agarwal)
+ * Replace `PageRevision` with generic `Revision` model (Sage Abdullah)
 
 
 3.0 (xx.xx.xxxx) - IN DEVELOPMENT

docs/reference/pages/model_reference.rst

@@ -484,25 +484,43 @@ The ``locale`` and ``translation_key`` fields have a unique key constraint to pr
     .. autoattribute:: localized
 
 
-.. _page-revision-model-ref:
+.. _revision-model-ref:
 
-``PageRevision``
+``Revision``
 ================
 
-Every time a page is edited a new ``PageRevision`` is created and saved to the database. It can be used to find the full history of all changes that have been made to a page and it also provides a place for new changes to be kept before going live.
+Every time a page is edited a new ``Revision`` is created and saved to the database. It can be used to find the full history of all changes that have been made to a page and it also provides a place for new changes to be kept before going live.
 
 - Revisions can be created from any :class:`~wagtail.models.Page` object by calling its :meth:`~Page.save_revision` method
-- The content of the page is JSON-serialisable and stored in the :attr:`~PageRevision.content` field
-- You can retrieve a ``PageRevision`` as a :class:`~wagtail.models.Page` object by calling the :meth:`~PageRevision.as_page_object` method
+- The content of the page is JSON-serialisable and stored in the :attr:`~Revision.content` field
+- You can retrieve a ``Revision`` as a :class:`~wagtail.models.Page` object by calling the :meth:`~Revision.as_page_object` method
+
+.. versionchanged:: 4.0
+
+    The model has been renamed from ``PageRevision`` to ``Revision`` and it now references the ``Page`` model using a combination of an ``object_id`` :class:`~django.db.models.CharField` and foreign keys to :class:`~django.contrib.contenttypes.models.ContentType`.
 
 Database fields
 ~~~~~~~~~~~~~~~
 
-.. class:: PageRevision
+.. class:: Revision
 
-    .. attribute:: page
+    .. attribute:: content_type
 
-        (foreign key to :class:`~wagtail.models.Page`)
+        (foreign key to :class:`~django.contrib.contenttypes.models.ContentType`)
+
+        This is the content type of the object this revision belongs to. For page revisions, this means the content type of the specific page type.
+
+    .. attribute:: base_content_type
+
+        (foreign key to :class:`~django.contrib.contenttypes.models.ContentType`)
+
+        This is the base content type of the object this revision belongs to. For page revisions, this means the content type of the default page type.
+
+    .. attribute:: object_id
+
+        (string)
+
+        This represents the id of the object this revision belongs to.
 
     .. attribute:: submitted_for_moderation
 
@@ -536,38 +554,52 @@ Database fields
 Managers
 ~~~~~~~~
 
-.. class:: PageRevision
+.. class:: Revision
     :noindex:
 
     .. attribute:: objects
 
-        This manager is used to retrieve all of the ``PageRevision`` objects in the database
+        This manager is used to retrieve all of the ``Revision`` objects in the database
 
         Example:
 
         .. code-block:: python
 
-            PageRevision.objects.all()
+            Revision.objects.all()
+
+    .. attribute:: page_revisions
+
+        This manager is used to retrieve all of the ``Revision`` objects that belong to pages.
+
+        Example:
+
+        .. code-block:: python
+
+            Revision.page_revisions.all()
+
+        .. versionadded:: 4.0
+
+            This manager is added as a shorthand to retrieve page revisions.
 
     .. attribute:: submitted_revisions
 
-        This manager is used to retrieve all of the ``PageRevision`` objects that are awaiting moderator approval
+        This manager is used to retrieve all of the ``Revision`` objects that are awaiting moderator approval
 
         Example:
 
         .. code-block:: python
 
-            PageRevision.submitted_revisions.all()
+            Revision.submitted_revisions.all()
 
 Methods and properties
 ~~~~~~~~~~~~~~~~~~~~~~
 
-.. class:: PageRevision
+.. class:: Revision
     :noindex:
 
     .. automethod:: as_page_object
 
-        This method retrieves this revision as an instance of its :class:`~wagtail.models.Page` subclass.
+        This method retrieves this revision as an instance of its :class:`~wagtail.models.Page` subclass. This assumes that the revision belongs to a page.
 
     .. automethod:: approve_moderation
 
@@ -579,11 +611,15 @@ Methods and properties
 
     .. automethod:: is_latest_revision
 
-        Returns ``True`` if this revision is its page's latest revision
+        Returns ``True`` if this revision is the object's latest revision
 
     .. automethod:: publish
 
-        Calling this will copy the content of this revision into the live page object. If the page is in draft, it will be published.
+        Calling this will copy the content of this revision into the live object. If the object is in draft, it will be published.
+
+    .. autoattribute:: content_object
+
+        This property returns the object this revision belongs to.
 
 ``GroupPagePermission``
 =======================

docs/reference/signals.rst

@@ -3,7 +3,7 @@
 Signals
 =======
 
-Wagtail's :ref:`page-revision-model-ref` and :ref:`page-model-ref` implement
+Wagtail's :ref:`revision-model-ref` and :ref:`page-model-ref` implement
 :doc:`Signals <topics/signals>` from ``django.dispatch``.
 Signals are useful for creating side-effects from page publish/unpublish events.
 
@@ -13,11 +13,11 @@ For example, you could use signals to send publish notifications to a messaging
 ``page_published``
 ------------------
 
-This signal is emitted from a ``PageRevision`` when a revision is set to `published`.
+This signal is emitted from a ``Revision`` when a page revision is set to `published`.
 
 :sender: The page ``class``.
 :instance: The specific ``Page`` instance.
-:revision: The ``PageRevision`` that was published.
+:revision: The ``Revision`` that was published.
 :kwargs: Any other arguments passed to ``page_published.send()``.
 
 To listen to a signal, implement ``page_published.connect(receiver, sender, **kwargs)``. Here's a simple

docs/releases/4.0.md

@@ -15,6 +15,7 @@ depth: 1
  * Convert various pages in the documentation to Markdown (Daniel Kirkham)
  * Add `base_url_path` to `ModelAdmin` so that the default URL structure of app_label/model_name can be overridden (Vu Pham, Khanh Hoang)
  * Add `full_url` to the API output of `ImageRenditionField` (Paarth Agarwal)
+ * Replace `PageRevision` with generic `Revision` model (Sage Abdullah)
 
 ### Bug fixes
 
@@ -26,3 +27,11 @@ depth: 1
 ### `base_url_path` keyword argument added to AdminURLHelper
 
 The `wagtail.contrib.modeladmin.helpers.AdminURLHelper` class now accepts a `base_url_path` keyword argument on its constructor. Custom subclasses of this class should be updated to accept this keyword argument.
+
+### `PageRevision` replaced with `Revision`
+
+The `PageRevision` model has been replaced with a generic `Revision` model. If you use the `PageRevision` model in your code, make sure that:
+
+ * Creation of `PageRevision` objects should be updated to create `Revision` objects using the page's `id` as the `object_id`, the default `Page` model's content type as the `base_content_type`, and the page's specific content type as the `content_type`.
+ * Queries that use the `PageRevision.objects` manager should be updated to use the `Revision.page_revision` manager.
+ * Queries for `Page` objects that use `PageRevision.page_id` should be updated to cast the `Revision.object_id` to an integer before using it in the query.