update

package/vendor/liquid/liquid/src/Liquid/Context.php

@@ -296,8 +296,11 @@ class Context
 			$key = preg_replace("|\[([0-9]+)\]|", ".$1", $key);
 		} elseif (preg_match("|\[[0-9a-z._]+\]|", $key, $matches)) {
 			$index = $this->get(str_replace(["[", "]"], "", $matches[0]));
-			if (strlen($index)) {
-				$key = preg_replace("|\[([0-9a-z._]+)\]|", ".$index", $key);
+			if ($index !== null && (is_scalar($index) || (is_object($index) && method_exists($index, '__toString')))) {
+				$index = (string) $index;
+				if (strlen($index)) {
+					$key = preg_replace("|\[([0-9a-z._]+)\]|", ".$index", $key);
+				}
 			}
 		}
 

package/vendor/liquid/liquid/src/Liquid/StandardFilters.php

@@ -416,6 +416,14 @@ class StandardFilters
 	 */
 	public static function remove($input, $string)
 	{
+		if ($input === null) {
+			return '';
+		}
+
+		if ($string === null) {
+			$string = '';
+		}
+
 		return str_replace($string, '', $input);
 	}
 
@@ -430,6 +438,14 @@ class StandardFilters
 	 */
 	public static function remove_first($input, $string)
 	{
+		if ($input === null) {
+			return '';
+		}
+
+		if ($string === null || $string === '') {
+			return $input;
+		}
+
 		if (($pos = strpos($input, $string)) !== false) {
 			$input = substr_replace($input, '', $pos, strlen($string));
 		}
@@ -449,6 +465,18 @@ class StandardFilters
 	 */
 	public static function replace($input, $string, $replacement = '')
 	{
+		if ($input === null) {
+			return '';
+		}
+
+		if ($string === null) {
+			$string = '';
+		}
+
+		if ($replacement === null) {
+			$replacement = '';
+		}
+
 		return str_replace($string, $replacement, $input);
 	}
 
@@ -464,6 +492,18 @@ class StandardFilters
 	 */
 	public static function replace_first($input, $string, $replacement = '')
 	{
+		if ($input === null) {
+			return '';
+		}
+
+		if ($string === null || $string === '') {
+			return $input;
+		}
+
+		if ($replacement === null) {
+			$replacement = '';
+		}
+
 		if (($pos = strpos($input, $string)) !== false) {
 			$input = substr_replace($input, $replacement, $pos, strlen($string));
 		}
@@ -522,6 +562,10 @@ class StandardFilters
 	 */
 	public static function size($input)
 	{
+		if ($input === null) {
+			return 0;
+		}
+
 		if ($input instanceof \Iterator) {
 			return iterator_count($input);
 		}
@@ -542,7 +586,7 @@ class StandardFilters
 		}
 
 		// only plain values and stringable objects left at this point
-		return strlen($input);
+		return strlen((string)$input);
 	}
 
 
@@ -640,6 +684,10 @@ class StandardFilters
 	 */
 	public static function strip($input)
 	{
+		if ($input === null) {
+			return '';
+		}
+
 		return trim($input);
 	}
 
@@ -697,7 +745,12 @@ class StandardFilters
 	 */
 	public static function truncate($input, $characters = 100, $ending = '...')
 	{
+		if ($input === null) {
+			return '';
+		}
+
 		if (is_string($input) || is_numeric($input)) {
+			$input = (string)$input;
 			if (strlen($input) > $characters) {
 				return mb_substr($input, 0, $characters) . $ending;
 			}