FIX: Use Hierarchy::prepopulateTreeDataCache() in CMS.

src/Versioned.php

@@ -2311,6 +2311,21 @@ public static function get_versionnumber_by_stage($class, $stage, $id, $cache =
         return $version ?: null;
     }
 
+    /**
+     * Hook into {@link Hierarchy::prepopulateTreeDataCache}.
+     *
+     * @param DataList|array $recordList The list of records to prepopulate caches for. Null for all records.
+     * @param array $options A map of hints about what should be cached. "numChildrenMethod" and
+     *                       "childrenMethod" are allowed keys.
+     */
+    public function onPrepopulateTreeDataCache($recordList = null, array $options = [])
+    {
+        $idList = is_array($recordList) ? $recordList :
+            ($recordList instanceof DataList ? $recordList->column('ID') : null);
+        self::prepopulate_versionnumber_cache($this->owner->baseClass(), Versioned::DRAFT, $idList);
+        self::prepopulate_versionnumber_cache($this->owner->baseClass(), Versioned::LIVE, $idList);
+    }
+
     /**
      * Pre-populate the cache for Versioned::get_versionnumber_by_stage() for
      * a list of record IDs, for more efficient database querying.  If $idList

tests/php/VersionedNumberCacheTest.php

@@ -100,7 +100,7 @@ public function testVersionNumberCache($stage, $ID, $cache, $expected)
      */
     public function testPrepopulatedVersionNumberCache($stage, $ID, $cache, $expected)
     {
-        Versioned::prepopulate_versionnumber_cache(TestObject::class, $stage);
+        TestObject::singleton()->onPrepopulateTreeDataCache();
         $actual = Versioned::get_versionnumber_by_stage(TestObject::class, $stage, self::${$ID}, $cache);
         $this->assertEquals(self::$expectedVersions[$expected], $actual);
     }