[REF] Use getter rather than passing variable

txnType is a required parameter for recurring & unused for single. This switches to retrieving
it as needed rather than passing it around. It removes one check for whether it is
set because the abort will exit if not

CRM/Core/Payment/PayPalIPN.php

@@ -70,13 +70,7 @@ public function retrieve($name, $type, $abort = TRUE) {
    * @throws \CiviCRM_API3_Exception
    */
   public function recur($input, $recur, $contribution, $first) {
-    if (!isset($input['txnType'])) {
-      Civi::log()->debug('PayPalIPN: Could not find txn_type in input request');
-      echo "Failure: Invalid parameters<p>";
-      return;
-    }
-
-    if ($input['txnType'] === 'subscr_payment' &&
+    if ($this->getTrxnType() === 'subscr_payment' &&
       $input['paymentStatus'] !== 'Completed'
     ) {
       Civi::log()->debug('PayPalIPN: Ignore all IPN payments that are not completed');
@@ -94,9 +88,8 @@ public function recur($input, $recur, $contribution, $first) {
     $now = date('YmdHis');
 
     // set transaction type
-    $txnType = $this->getTrxnType();
     $contributionStatuses = array_flip(CRM_Contribute_BAO_Contribution::buildOptions('contribution_status_id', 'validate'));
-    switch ($txnType) {
+    switch ($this->getTrxnType()) {
       case 'subscr_signup':
         $recur->create_date = $now;
         // sometimes subscr_signup response come after the subscr_payment and set to pending mode.
@@ -151,7 +144,7 @@ public function recur($input, $recur, $contribution, $first) {
 
     $recur->save();
 
-    if ($txnType !== 'subscr_payment') {
+    if ($this->getTrxnType() !== 'subscr_payment') {
       return;
     }
 
@@ -336,7 +329,6 @@ public function main() {
    */
   public function getInput(&$input) {
     $billingID = CRM_Core_BAO_LocationType::getBilling();
-    $input['txnType'] = $this->retrieve('txn_type', 'String', FALSE);
     $input['paymentStatus'] = $this->retrieve('payment_status', 'String', FALSE);
     $input['invoice'] = $this->retrieve('invoice', 'String', TRUE);
     $input['amount'] = $this->retrieve('mc_gross', 'Money', FALSE);
@@ -428,8 +420,7 @@ public function getPayPalPaymentProcessorID(array $input, ?int $contributionRecu
    * @throws \CRM_Core_Exception
    */
   protected function getTrxnType() {
-    $txnType = $this->retrieve('txn_type', 'String');
-    return $txnType;
+    return $this->retrieve('txn_type', 'String');
   }
 
   /**