Crud: Repeatable field return '[]' string after deleting all entries

[themagnifico]

Bug report

What I did

• I defined a repeatable field
• I entered some entries
• I saved the entity
• then I edited the repeatable field deleting ALL the entries
• I saved the entity

What I expected to happen

I expected to get a null value as if the repeatable field had never been compiled.

What happened

The field return a string (2) "[]"

What I've already tried to fix it

Asking if this is the expected behavior

Backpack, Laravel, PHP, DB version

When I run php artisan backpack:version the output is:

PHP VERSION:

PHP 7.3.15 (cli) (built: Feb 18 2020 12:45:47) ( ZTS MSVC15 (Visual C++ 2017) x64 )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.15, Copyright (c) 1998-2018 Zend Technologies
with Xdebug v2.9.4, Copyright (c) 2002-2020, by Derick Rethans

LARAVEL VERSION:

v7.11.0@f4563bd2e0875c59a1f7967abdbe5cef7f240117

BACKPACK VERSION:

4.1.4@4303aa07ec0c597abfcfe83896558ca6e98f0d6a

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[justinmoh]

It's the expected behaviour.

This is actually a question of "what is the default value of the repeatable input". Please note that the input value of repeatable will always be string as was intended to be used with json_decode.

Now, if you create a repeatable, leave it untouched and submit, it will give you a json string, and decode it it'll show something like:

array:1 [
    0 => array:3 [
        "name" => "",
        "email" => "",
        "mobile" => "",
    ]
]

If you click on the cross and delete the default element, you know that under the hood the array is removing one of its associating child element. In our case, it removes array[0], and the remaining is an empty array.

In such situation, __repeatable field return '[]' string after deleting all entries__ is an expected behaviour. AFAIK it is intact with other backpack input element concerning json.

If you think such behaviour gives you some troubles, you can illustrate an example situation, perhaps it worths further discussion.

[themagnifico]

It makes totally sense.

I had a default null value in the repeatable column entries because i added that column in an existent table.

I am going to close the issue.

Thanks a lot.

[tabacitu]

Wow - thanks a lot for the detailed explanation @justinmoh - I couldn't explain it so clearly even if I tried. Good job!