Don't check for impossible error condition in mb_strlen

Author: alexdowad

ext/mbstring/libmbfl/mbfl/mbfilter.c

@@ -461,9 +461,7 @@ mbfl_strlen(const mbfl_string *string)
 		  string->encoding,
 		  &mbfl_encoding_wchar,
 		  filter_count_output, 0, &len);
-		if (filter == NULL) {
-			return (size_t) -1;
-		}
+		ZEND_ASSERT(filter);
 		/* count */
 		n = string->len;
 		p = string->val;

ext/mbstring/mbstring.c

@@ -1823,11 +1823,7 @@ PHP_FUNCTION(mb_strlen)
 		RETURN_THROWS();
 	}
 
-	size_t n = mbfl_strlen(&string);
-	/* Only way this can fail is if the conversion creation fails
-	 * this would imply some sort of memory allocation failure which is a bug */
-	ZEND_ASSERT(!mbfl_is_error(n));
-	RETVAL_LONG(n);
+	RETVAL_LONG(mbfl_strlen(&string));
 }
 /* }}} */