From 5e98f18bbf9aa294c7fdcb692900b53dae129780 Mon Sep 17 00:00:00 2001
From: Brian Matovu <mtvbrianking@gmail.com>
Date: Tue, 30 Mar 2021 11:11:56 +0300
Subject: [PATCH 1/2] Test unknown property from string fails

---
 tests/Recurr/Test/RuleTest.php | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/Recurr/Test/RuleTest.php b/tests/Recurr/Test/RuleTest.php
index 3471f34..64e3e70 100644
--- a/tests/Recurr/Test/RuleTest.php
+++ b/tests/Recurr/Test/RuleTest.php
@@ -461,6 +461,14 @@ public function testBadWeekStart()
     {
         $this->rule->setWeekStart('monday');
     }
+    
+    /**
+     * @expectedException \Recurr\Exception\InvalidRRule
+     */
+    public function testUnknownPropertyFromStringThrowsException()
+    {
+        $this->rule->loadFromString('FREQ=MONTHLY;BYDAY=-1FR;COUNT=10;SKIP=2');
+    }
 
     /**
      * @dataProvider exampleRruleProvider

From a1c4760a9ec1317b3284301ff91337f01180e827 Mon Sep 17 00:00:00 2001
From: Brian Matovu <mtvbrianking@gmail.com>
Date: Tue, 30 Mar 2021 11:16:23 +0300
Subject: [PATCH 2/2] Validate unknown RRULE properties.

---
 src/Recurr/Rule.php | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/src/Recurr/Rule.php b/src/Recurr/Rule.php
index dfcf40f..32224d0 100644
--- a/src/Recurr/Rule.php
+++ b/src/Recurr/Rule.php
@@ -174,6 +174,29 @@ class Rule
 
     /** @var array */
     protected $exDates = array();
+    
+    /** @var array */
+    protected $properties = [
+        'FREQ',
+        'DTSTART',
+        'DTEND',
+        'UNTIL',
+        'UNTIL',
+        'COUNT',
+        'INTERVAL',
+        'BYSECOND',
+        'BYMINUTE',
+        'BYHOUR',
+        'BYDAY',
+        'BYMONTHDAY',
+        'BYYEARDAY',
+        'BYWEEKNO',
+        'BYMONTH',
+        'BYSETPOS',
+        'WKST',
+        'RDATE',
+        'EXDATE'
+    ];
 
     /**
      * Construct a new Rule.
@@ -431,6 +454,18 @@ public function loadFromArray($parts)
         if (isset($parts['EXDATE'])) {
             $this->setExDates(explode(',', $parts['EXDATE']));
         }
+        
+        // UNKNOWN PROPERTIES
+        $invalidProperties = array_values(array_diff(array_keys($parts), $this->properties));
+
+        if($invalidProperties) {
+            $msg = array_pop($invalidProperties);
+
+            if ($invalidProperties)
+                $msg = implode(', ', $invalidProperties).', and '.$msg;
+
+            throw new InvalidRRule('Unknown RRULE property: '.$msg);
+        }
 
         return $this;
     }