Existing files cleared on Channel Form submission

[chrisdaviesweb]

Submitting a channel form via AJAX where an entry is being 'edited' and contains a 'file grid' field, causes any existing files to be cleared.

Submitting the exact same form without AJAX, works correctly. Existing files are NOT cleared.

It is possible to replicate this, using a very basic channel, containing a 'file grid' field:

{exp:channel:form channel="channel_name" return="/somewhere" json="yes" entry_id="1"}

    <input type="text" name="title" id="title" value="{title}">
    <input type="text" name="url_title" id="url_title" value="{url_title}">

    {field:my_file_grid_field}

    <input type="submit" />

{/exp:channel:form}

To simplify, I have tested with a basic AJAX submission using jQuery Form Plugin (http://malsup.com/jquery/form/)

$('form#cform').on('submit', function (e) {
    e.preventDefault();
    $('form#cform').ajaxSubmit(function() { 
        console.log('submitted');
    });
});

Expression Engine 6 beta 3 PHP 7.4 MySQL 5.7

[ops-andy]

@chrisdaviesweb can you confirm this only happens if you load the channel form and make no changes and then submit? I can replicate it in that manner. However, If I load the channel form, add another row to the file grid with an image, it doesn't seem to erase previous entries for me. It's a bug either way, but just making sure we're seeing similar results.

[ops-andy]

also noting this happens in EE5.3 as well.

[chrisdaviesweb]

@ops-andy Just checked and thats the same here. It's only if the field isn't modified that the files are wiped on save.

[intoeetive]

When file upload is involved, AJAX calls need to be somewhat more complex.

This example works fine, no files are lost