Fix DisallowAttributesJoiningSniff for Attribute with trailing comma

Author: javer

SlevomatCodingStandard/Helpers/AttributeHelper.php

@@ -58,6 +58,11 @@ public static function getAttributes(File $phpcsFile, int $attributeOpenerPointe
 
 		do {
 			$attributeNameStartPointer = TokenHelper::findNextEffective($phpcsFile, $actualPointer + 1, $attributeCloserPointer);
+
+			if ($attributeNameStartPointer === null) {
+				break;
+			}
+
 			$attributeNameEndPointer = TokenHelper::findNextExcluding(
 				$phpcsFile,
 				TokenHelper::getNameTokenCodes(),

tests/Sniffs/Attributes/data/disallowedAttributesJoiningNoErrors.php

@@ -15,6 +15,7 @@ public function __construct(#[Attribute1] #[Attribute2('var')]
 
 #[Attribute1] #[Attribute2('var')]
 #[Attribute3(option: PDO::class, option2: true, option3: 'False')]
+#[Attribute4,]
 function testFunc($test)
 {
 }