TYPO3 Core

I tested a lot.
I've cranked my php-settings max_input_vars from 1000 to 10000 and max_input_level from 64 to 128 with no effort.

Going down from 58 bands to 40 down to 30 down to 20, having 2 stages with 3 days each: cant't add another day
Having 30, 20 and 10 bands, adding two stages was possible. adding a day to a stage wasn't. deleting a stage also wasn't possible.

Maybe it's not the number of IRRE elements, maybe its something other:

+ create a year
+ open year and create some bands -> save
+ open year and create one stage -> save
+ open year, unfold the stage and create a date ->save
+ open year, create a second stage -> save
+ open year, unfold a stage, create a date -> nothing happens!

Looks like same issues as https://forge.typo3.org/issues/100937

OK, now I was able to reproduce the problem. However with just a few records. One year, one band and one stage. After I add a 2nd stage, no data is saved any more. Reason for this seems to be your custom form element runningorderoverview. As soon as I remove this from the TCA, it is possible to add additional data again.

Thanks, Torben.
But I see no issues in my custom form element runningorderoverview . Compared to the documentation on docs.typo3.org it should work. And it worked in TYPO3 9.x .

You custom element creates invalid HTML. Since TYPO3 formengine also relies on JavaScript to evaluate several things in frontend (e.g. validation, evaluate if data should be saved), I suppose this somehow breaks if your custom formengine elemente does not create valid HTML. In this case, the POST parameter doSave is not set to 1 by TYPO3 formengine JavaScript when your formelement is active.

You currently have to many closing div elements, since you open the div before the foreach loop, but add a closing div inside your loop. Fix it by adding the closing div outside of the loop as shown below

    $resultTable .= '</tr></tbody></table>';
}
$resultTable .= '</div>';
return $resultTable;

Also make sure to use the none type for your custom formengine element, since all other custom types (e.g. user or passthrough) actually expect a database field to exist. So TCA for your element is:

'runningorderoverview' => array(
    'label' => 'RunningOrder',
    'config' => array(
        'type' => 'none',
        'renderType' => 'RunningorderOverview'
    )
),

With those modifications, new elements can be saved. Yes, I know this is somehow not really a satisfying experience, but the actual reason for the problem is however most likely custom code and not a TYPO3 core problem. No idea why this worked in TYPO3 9.

If you confirm, that this finally fixes your problem, I will update the formengine docs, so it is more clear, that custom elements must contain valid HTML.

I also suggest to add a composer.json (see https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/ExtensionArchitecture/FileStructure/ComposerJson.html) and please see my message to you on TYPO3 slack.

Thank you a lot. This resolves this issue!