From 1b89512c38239456eb07261f9c7607f2a6f04865 Mon Sep 17 00:00:00 2001
From: Joel Stein <joel@mediatrix.digital>
Date: Wed, 1 Feb 2023 17:40:47 -0600
Subject: [PATCH] Added support for comma-separated BYMONTHDAY value

---
 src/Property/Event/RecurrenceRule.php | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Property/Event/RecurrenceRule.php b/src/Property/Event/RecurrenceRule.php
index a424d254..25f2526a 100644
--- a/src/Property/Event/RecurrenceRule.php
+++ b/src/Property/Event/RecurrenceRule.php
@@ -448,8 +448,10 @@ public function setByYearDay($day)
      */
     public function setByMonthDay($day)
     {
-        if (!is_integer($day) || $day > 31 || $day < -31 || $day === 0) {
-            throw new InvalidArgumentException('Invalid value for BYMONTHDAY');
+        foreach (explode(',', $day) as $value) {
+            if (!filter_var($value, FILTER_VALIDATE_INT, ['options' => ['min_range' => -31, 'max_range' => 31]]) || (int) $value === 0) {
+                throw new InvalidArgumentException('Invalid value for BYMONTHDAY');
+            }
         }
 
         $this->byMonthDay = $day;