Fix notices in upgrade functions, chines tokenizer, and summarizer, a=chris

diff --git a/src/library/UpgradeFunctions.php b/src/library/UpgradeFunctions.php
index 9e8b62980..cfbbbec0b 100644
--- a/src/library/UpgradeFunctions.php
+++ b/src/library/UpgradeFunctions.php
@@ -107,9 +107,10 @@ function upgradePublicHelpWiki(&$db)
         foreach ($locale_pages as $page_name => $page_content) {
             $page_info = $group_model->getPageInfoByName(C\PUBLIC_GROUP_ID,
                 $page_name, $locale_tag, "edit");
-            if ($page_content != $page_info['PAGE'] &&
-                (in_array($page_info['EDIT_COMMENT'], ['upgrade', 'create']) ||
-                !empty($page_info['PUBDATE']) &&
+            if (empty($page_info) ||
+                ($page_content != $page_info['PAGE'] &&
+                (in_array($page_info['EDIT_COMMENT'], ['upgrade', 'create'])))||
+                (!empty($page_info['PUBDATE']) &&
                 $page_info['PUBDATE'] < 1555802108) ) {
                 $group_model->setPageName(C\ROOT_ID, C\PUBLIC_GROUP_ID,
                     $page_name, $page_content, $locale_tag, "upgrade",
diff --git a/src/library/summarizers/Summarizer.php b/src/library/summarizers/Summarizer.php
index 032c23b2b..4d40cb758 100644
--- a/src/library/summarizers/Summarizer.php
+++ b/src/library/summarizers/Summarizer.php
@@ -202,9 +202,11 @@ class Summarizer
      */
      public static function removePunctuation($sentences)
      {
-        foreach ($sentences as $key => $sentence) {
-            $sentences[$key] = trim(preg_replace('/[' . C\PUNCT . ']+/iu', ' ',
-                $sentence));
+        if (is_array($sentences)) {
+            foreach ($sentences as $key => $sentence) {
+                $sentences[$key] = trim(preg_replace('/[' . C\PUNCT . ']+/iu',
+                    ' ', $sentence));
+            }
         }
         return $sentences;
      }
diff --git a/src/locale/zh_CN/resources/Tokenizer.php b/src/locale/zh_CN/resources/Tokenizer.php
index 0daf63e11..aade93e7f 100755
--- a/src/locale/zh_CN/resources/Tokenizer.php
+++ b/src/locale/zh_CN/resources/Tokenizer.php
@@ -404,7 +404,11 @@ class Tokenizer
             self::$traditional_simplified_map =
                 unserialize(gzdecode(file_get_contents($path)));
         }
-        $chars = preg_split('//u', $text, null, PREG_SPLIT_NO_EMPTY);
+        if (is_string($text)) {
+            $chars = preg_split('//u', $text, null, PREG_SPLIT_NO_EMPTY);
+        } else {
+            return $text;
+        }
         $num_chars = count($chars);
         for($i = 0; $i < $num_chars; $i++) {
             if (isset(self::$traditional_simplified_map[$chars[$i]])) {