Cannot map "0" to a numeric or text field in a Civi form

[nc3man]

When the number 0 (or text "0") is entered in a Caldera form, either directly in an input box, or as a value from a radio selection, 0 appears to get replaced by "null" at some point prior to running a CiviCRM Form Processor which needs this parameter. If this is an expected parameter on the Civi form processor, you get a FAIL when submitted.

I discovered this on a more complicated form, but I created a super simple example to illustrate the error. The Caldera form is named test_input_zero and is exported as test_input_zero-export.json. The Civi Form Processor that is used as a processor in test_input_zero is test_num_civi and is exported as test_num_civi.json. I zipped both exports to attach here
test_input_zero.zip. I'm also attaching a screenshot of the McRestFace Log after entering a "1" for the numeric field in test_input_zero. It is correctly passed through as input to test_num_civi processor in CiviCRM.

Entering the number 0 shows that null is passed to test_num_civi and so the processor fails as also shown in the McRestFaceLog

There is no issue with any other non-zero integer, including negative numbers, being passed through the interface. 0 just is interpreted as null for some reason. Is there a setting to prevent this?

[nc3man]

Hunting through the code, I don't see where a zero(0) might get mapped to null. I do see that once that value is null, then the corresponding key in the params array is removed, which is why we get the message "Mandatory key(s) missing ..."
So the logic to remove the key may be at line 161 in class-formprocessor-processor.php

// Remove null values from array otherwise we might get uggly errors.
    foreach($result as $key => $val) {
      if ($val === null) {
        unset($result[$key]);
      }
    }

[nc3man]

I removed the test_num_civi processor and just added the Auto Responder to verify that Caldera Forms interprets the "0" input correctly. It appears to be somehow being transformed in this plugin.

[nc3man]

Just to be sure that I hadn't mangled something with learning about this plugin on our test site, on our live site I did a completely fresh install of CiviCRM extensions Action-Provider and Form-Processor, and fresh installs of Caldera Forms, Integration of CiviCRM Form Processor with Caldera Forms, Connector to CiviCRM with CiviMcRestFace so I could see the logging (set up a local connection with our local Civi). I imported the two examples zipped up here, and repeated the test. The difference was that I set the field to be short text instead of numeric on both sides. Same issue - "0" does not make it through but other characters do.

[nc3man]

For a short term fix, I can just pass characters to the Civi Form and then map to 0. I don't understand how the Map Value action works. Can someone show me an example, please? I want to map "Y" to numeric 1 and "N" to numeric 0. I also want the reverse map: 1=>"Y" and 0=>"N" for retrieving defaults. I tried guessing at the correct JSON format for the mapping, but my guesses have not worked. One simple example is all I need and this would at least give us a workaround for our current application which is on a schedule to be completed soon.

[nc3man]

I have a short term fix for our use case. In the Civi Form Processor, I did not make the primary inputs required and set the default to 0. So, even though a 0 on the Caldera side gets mapped to null by the Integration plugin, the default correctly sets the value to 0. I also made the variables in the Civi Form Processor of type Custom Options with values 0 & 1, labels "Yes" and "No". Screenshot is from the McRestFace log. Everything is working for our application this way, but the 0 entered in the form's "newsletter" field should still not be set to null, imo. I still would like to understand how to set the Action: Map Value to work with a JSON example.