Fix article counting logic in DerivedPageDataUpdater

Use old state of the page if we have it.

Bug: T200823
Change-Id: Iff29731a127ef32baec5970dcbc25a0a5c3eb4d9

diff --git a/includes/Storage/DerivedPageDataUpdater.php b/includes/Storage/DerivedPageDataUpdater.php
index 6f241ba..4c51003 100644 (file)
--- a/includes/Storage/DerivedPageDataUpdater.php
+++ b/includes/Storage/DerivedPageDataUpdater.php
@@ -152,10 +152,21 @@ class DerivedPageDataUpdater implements IDBAccessObject {
        /**
         * The state of the relevant row in page table before the edit.
         * This is determined by the first call to grabCurrentRevision, prepareContent,
-        * or prepareUpdate.
+        * or prepareUpdate (so it is only accessible in 'knows-current' or a later stage).
         * If pageState was not initialized when prepareUpdate() is called, prepareUpdate() will
         * attempt to emulate the state of the page table before the edit.
         *
+        * Contains the following fields:
+        * - oldRevision (RevisionRecord|null): the revision that was current before the change
+        *   associated with this update. Might not be set, use getOldRevision() instead of direct
+        *   access.
+        * - oldId (int|null): the id of the above revision. 0 if there is no such revision (the change
+        *   was about creating a new page); null if not known (that should not happen).
+        * - oldIsRedirect (bool|null): whether the page was a redirect before the change. Lazy-loaded,
+        *   can be null; use wasRedirect() instead of direct access.
+        * - oldCountable (bool|null): whether the page was countable before the change (or null
+        *   if we don't have that information)
+        *
         * @var array
         */
        private $pageState = null;
@@ -958,7 +969,7 @@ class DerivedPageDataUpdater implements IDBAccessObject {
         *    - null: if created is false, don't update the article count; if created
         *      is true, do update the article count
         *    - 'no-change': don't update the article count, ever
-        *
+        *    When set to null, pageState['oldCountable'] will be used instead if available.
         */
        public function prepareUpdate( RevisionRecord $revision, array $options = [] ) {
                Assert::parameter(
@@ -1469,6 +1480,9 @@ class DerivedPageDataUpdater implements IDBAccessObject {
                } elseif ( $this->options['oldcountable'] !== null ) {
                        $good = (int)$this->isCountable()
                                - (int)$this->options['oldcountable'];
+               } elseif ( isset( $this->pageState['oldCountable'] ) ) {
+                       $good = (int)$this->isCountable()
+                               - (int)$this->pageState['oldCountable'];
                } else {
                        $good = 0;
                }