API Add strong-typing to SearchContext::getQuery() $limit param

Seems the two search context implementations had different ideas about
what was correct for the limit parameter, and the basic one wasn't even
handling the values correctly.

src/ORM/Search/BasicSearchContext.php

@@ -33,24 +33,16 @@ class BasicSearchContext extends SearchContext
      *  If a filter is applied to a relationship in dot notation,
      *  the parameter name should have the dots replaced with double underscores,
      *  for example "Comments__Name" instead of the filter name "Comments.Name".
-     * @param array|bool|string $sort Field to sort on.
-     * @param array|null|string $limit
+     * @param array|false|string $sort Field to sort on.
+     * @param int|array|null $limit
      * @param SS_List $existingQuery
      */
-    public function getQuery($searchParams, $sort = false, $limit = false, $existingQuery = null): SS_List
+    public function getQuery($searchParams, $sort = false, int|array|null $limit = null, $existingQuery = null): SS_List
     {
         if (!$existingQuery || !is_a($existingQuery, SS_List::class)) {
             throw new InvalidArgumentException('getQuery requires a pre-existing SS_List list to be passed as $existingQuery.');
         }
 
-        if ((count(func_get_args()) >= 3) && (!in_array(gettype($limit), ['array', 'NULL', 'string']))) {
-            Deprecation::notice(
-                '5.1.0',
-                '$limit should be type of array|string|null'
-            );
-            $limit = null;
-        }
-
         $searchParams = $this->applySearchFilters($this->normaliseSearchParams($searchParams));
         $result = $this->applyGeneralSearchField($searchParams, $existingQuery);
 
@@ -65,7 +57,14 @@ public function getQuery($searchParams, $sort = false, $limit = false, $existing
         }
 
         // Limit must be last so that ArrayList results don't have an applied limit before they can be filtered/sorted.
-        $result = $result->limit($limit);
+        if (is_array($limit)) {
+            $result = $result->limit(
+                isset($limit['limit']) ? $limit['limit'] : null,
+                isset($limit['start']) ? $limit['start'] : null
+            );
+        } else {
+            $result = $result->limit($limit);
+        }
 
         return $result;
     }

src/ORM/Search/SearchContext.php

@@ -142,22 +142,15 @@ protected function applyBaseTableFields()
      *  If a filter is applied to a relationship in dot notation,
      *  the parameter name should have the dots replaced with double underscores,
      *  for example "Comments__Name" instead of the filter name "Comments.Name".
-     * @param array|bool|string $sort Database column to sort on.
+     * @param array|false|string $sort Database column to sort on.
      *  Falls back to {@link DataObject::$default_sort} if not provided.
      * @param int|array|null $limit
      * @param DataList $existingQuery
      * @return DataList<T>
      * @throws Exception
      */
-    public function getQuery($searchParams, $sort = false, $limit = false, $existingQuery = null)
+    public function getQuery($searchParams, $sort = false, int|array|null $limit = null, $existingQuery = null)
     {
-        if ((count(func_get_args()) >= 3) && (!in_array(gettype($limit), ['integer', 'array', 'NULL']))) {
-            Deprecation::notice(
-                '5.1.0',
-                '$limit should be type of int|array|null'
-            );
-            $limit = null;
-        }
         $this->setSearchParams($searchParams);
         $query = $this->prepareQuery($sort, $limit, $existingQuery);
         return $this->search($query);
@@ -197,9 +190,6 @@ private function prepareQuery($sort, $limit, ?DataList $existingQuery): DataList
         }
         $query = null;
         if ($existingQuery) {
-            if (!($existingQuery instanceof DataList)) {
-                throw new InvalidArgumentException("existingQuery must be DataList");
-            }
             if ($existingQuery->dataClass() != $this->modelClass) {
                 throw new InvalidArgumentException("existingQuery's dataClass is " . $existingQuery->dataClass()
                     . ", $this->modelClass expected.");