Fix payment processor selection persistence

[jitendrapurohit]

Overview

Fixes #32342 along with original fix included #10826

From #32342:

Steps to replicate:
Create a paid online event registration with price set of radio and checkbox price fields
Add pay later and one or more CC payment processor(s)
Go to event registration form live or on test mode.
Select a radio option and choose pay-later
Select any checkbox price option or change radio price option

Before

The payment processor selection switches to CC from pay-later and billing section is not exposed. I can replicate this issue in dmaster:

After

Fixed

Technical Details

On Hide: We now capture the currently selected payment_processor_id and store it in a data attribute on the billing block.

On Show: check for that data attribute.

If found: restore that specific processor.

If NOT found (and no other processor is currently active), fall back to the default behavior (selecting the processor marked checked=checked).

This preserves the fix for CRM-21038 (ensuring some processor is selected) while respecting explicit user choices during form updates.

Comments

Anything else you would like the reviewer to note

[civibot]

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[monishdeb]

To further optimize how about :

diff --git a/templates/CRM/common/paymentBlock.tpl b/templates/CRM/common/paymentBlock.tpl
index 8a3c00436b..842880ce41 100644
--- a/templates/CRM/common/paymentBlock.tpl
+++ b/templates/CRM/common/paymentBlock.tpl
@@ -24,7 +24,13 @@
     // might be that the unselecting of the processor should cause it
     // to be hidden (or removed) in which case it can go from this function.
     var billing_block = cj("div#billing-payment-block");
+    let payment_processor_options = cj('input[name="payment_processor_id"]');
     if (isHide) {
+      let checked = payment_processor_options.filter(':checked').val();
+      if (checked) {
+        billing_block.data('saved-ppid', checked);
+      }
+
       payment_options.hide();
       payment_processor.hide();
       payment_information.hide();
@@ -32,7 +38,7 @@
       // Ensure that jquery validation doesn't block submission when we don't need to fill in the billing details section
       cj('#billing-payment-block select.crm-select2').addClass('crm-no-validate');
       // also unset selected payment methods
-      cj('input[name="payment_processor_id"]').removeProp('checked');
+      payment_processor_options.removeProp('checked');
     }
     else {
       payment_options.show();
@@ -41,7 +47,16 @@
       billing_block.show();
       cj('#billing-payment-block select.crm-select2').removeClass('crm-no-validate');
       // also set selected payment methods
-      cj('input[name="payment_processor_id"][checked=checked]').prop('checked', true);
+
+      let saved = billing_block.data('saved-ppid');
+      if (saved && payment_processor_options.filter('[value="' + saved + '"]').length) {
+        payment_processor_options.filter('[value="' + saved + '"]').prop('checked', true);
+        billing_block.removeData('saved-ppid');
+      }
+      else if (!payment_processor_options.is(':checked')) {
+        // Fallback to default
+        payment_processor_options.filter('[checked=checked]').prop('checked', true);
+      }
     }
   }

just removed var declaration with let and use more generic variable to reduce variable declaration like restored_input and current_selection

[monishdeb]

Thanks for alternate PR. suggested a optimized patch~