What's the error?

Protostar
Warning
Extension Install: Field 'system_data' doesn't have a default value
Error
Error installing template
Unable to install new template from temporary folder.

Atum
Warning
JInstaller: :Install: File does not exist /home/juxresearch/j4.juxresearch.org/tmp/template_copy_58c006bf11a83/img
Template Install: Could not copy files from the files source.
Error
Error installing template
Unable to install new template from temporary folder.

Both are, however, copied to the tmp folder.

I'm not sure about the live installation, but in my local version the less files were missing from media/jui/.
I was having trouble compiling the Protostar css in NetBeans. Copying the files from a J3.6 site fixed the problem.

Confirmed Issue:

Test on:

Joomla! 4.0.0-dev
macOS Sierra, 10.12.3
Firefox 52.0 (64-bit)
PHP 7.0.15

MAMP 4.1.1

• PHP 7.0.15
• MySQLi 5.6.35

Protostar will be removed/replaced by a new bootstrap 4 template. To test the copy functionality try to copy the Atum (administrator) template

Can Tester have Info what to test now make Sense or where to Look? Like "Templates" or "Media Manager" not for testing cause ...?

@franz-wohlkoenig this is pre-Alpha so expect random failures and glitches all over...
But whatever reported will get fixed, either from the backend or the frontend team

got it, thanks @dgt41

Confirmed this issue. Someone good with database skill needs to check the following fields in #__extensions table:

• folder
• params
• custom_data
• system_data

When I look at the data from this table, many records contains empty data for these fields but in the create table command to create this table, these fields are marked as NOT NULL and don't have default value

Maybe @csthomas could help?

• folder is used for the plugins.
• params contains the extension settings (if saved)
• custom_data and system_data aren't used by core currently. I used the system_data column in J2.5 to store compatibility informations to give people a clue what to expect after upgrading to J3. See #5015. That code could be reimplemented into J3.x of course when J4 is released. I always assumed the custom_data is there for extensions to be used for whatever they want to store there.

@Bakual I asked about whether we should set default value for these fields as some records contain empty data for these fields/columns. Since these fields don't have default value (custom_data in this issue), it causes the issue with saving record - or we will have to add code to set value for this field empty while saving.

Take a look at https://github.com/joomla/joomla-cms/pull/14321/files#diff-6c6cf64555b76205d9e9e6451b6d2d3c

It should fix the problem at least in part. Can I ask for RTC (may be another test is required).

I never understood why we set "NOT NULL" for an optional field, but I'm not going to argue that anymore :)

The issue is that TEXT fields afaik can't have a default value specified. So the only solution is indeed setting the default value in PHP like @csthomas proposed. Or drop the "NOT NULL" requirement. I'd do the latter but people think for some reason it is important to not have NULL there.

I never understood why we set "NOT NULL" for an optional field

I have this same feeling.

I would set NULL also on every TEXT field, IMO this is the right way.

Should be fixed with the merge of #14750