Fixed Validation error when empty default customfield values

[inietov]

Description

This builds over #11724, in that PR I eliminate the required rule if it exists, but then if an input is set as an empty string and another rule on the custom field look for a date or a custom regex or something like that, the validator still fails.

So in this one instead of remove the required rule I replace it with a nullable rule, to let pass the validator in such cases.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Test Configuration:

• PHP version: 7.4.16
• MySQL version: 8.0.23
• Webserver version: nginx/1.19.8
• OS version: Debian 10

Checklist:

• I have read the Contributing documentation available here: https://snipe-it.readme.io/docs/contributing-overview
• I have formatted this PR according to the project guidelines: https://snipe-it.readme.io/docs/contributing-overview#pull-request-guidelines
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[snipe]

Do we need to do both? Remove required and also set to nullable?

[inietov]

I think so. The way I understand it is that "nullable" is the inverse of "required". Line 86 in the function that sets the custom fields rules:

[snipe]

Right, but in your code, it looks like you replaced removing required with adding nullable, so the $rules would be required|nullable, which seems weird? Unless I'm misreading?

[inietov]

No because I'm overwriting the rule in that position. If the validation rules are:

0=>'required'
1=>'date'

It replaces it with:

0=>'nullable'
1=>'date'

[snipe]

Thanks for the clarification!