TYPO3 Core

When an element (e.g. a content element) is new (i.e. not yet saved, does not have a uid), the suggest wizard fails with the following JavaScript error:

Uncaught (in promise) TypeError: can't convert null to object
    flattenObject https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/ajax/input-transformer.js?bust=1698147028:13
    flattenObject https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/ajax/input-transformer.js?bust=1698147028:13
    flattenObject https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/ajax/input-transformer.js?bust=1698147028:13
    toFormData https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/ajax/input-transformer.js?bust=1698147028:13
    byHeader https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/ajax/input-transformer.js?bust=1698147028:13
    post https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/ajax/ajax-request.js?bust=1698147028:31
    registerEvents https://t3starterpackage.ddev.site/_assets/081fa96a07de1dccb64a8a83e1567439/JavaScript/form-engine-suggest.js?bust=1698147028:52
    n https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/event/debounce-event.js?bust=1698147028:13
    setTimeout handler*debounce/< https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/event/debounce-event.js?bust=1698147028:13
    bindTo https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/event/regular-event.js?bust=1698147028:13
    registerEvents https://t3starterpackage.ddev.site/_assets/081fa96a07de1dccb64a8a83e1567439/JavaScript/form-engine-suggest.js?bust=1698147028:68
    FormEngineSuggest https://t3starterpackage.ddev.site/_assets/081fa96a07de1dccb64a8a83e1567439/JavaScript/form-engine-suggest.js?bust=1698147028:32
    promise callback*FormEngineSuggest https://t3starterpackage.ddev.site/_assets/081fa96a07de1dccb64a8a83e1567439/JavaScript/form-engine-suggest.js?bust=1698147028:32
    registerSuggest https://t3starterpackage.ddev.site/_assets/081fa96a07de1dccb64a8a83e1567439/JavaScript/form-engine/element/group-element.js?bust=1698147028:13
    GroupElement https://t3starterpackage.ddev.site/_assets/081fa96a07de1dccb64a8a83e1567439/JavaScript/form-engine/element/group-element.js?bust=1698147028:13
    promise callback*GroupElement https://t3starterpackage.ddev.site/_assets/081fa96a07de1dccb64a8a83e1567439/JavaScript/form-engine/element/group-element.js?bust=1698147028:13
    t https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-processor.js?bust=1698147028:13
    executeJavaScriptModuleInstruction https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-processor.js?bust=1698147028:13
    executeJavaScriptModuleInstruction https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-processor.js?bust=1698147028:13
    promise callback*executeJavaScriptModuleInstruction https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-processor.js?bust=1698147028:13
    javaScriptModuleInstruction https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-processor.js?bust=1698147028:13
    invoke https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-processor.js?bust=1698147028:13
    processItems https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-processor.js?bust=1698147028:13
    processItems https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-processor.js?bust=1698147028:13
    <anonymous> https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-handler.js?1698141040:13
    promise callback* https://t3starterpackage.ddev.site/_assets/1ee1d3e909b58d32e30dcea666dd3224/JavaScript/java-script-item-handler.js?1698141040:13
input-transformer.js:13:641

This is related to change https://review.typo3.org/c/Packages/TYPO3.CMS/+/80759 which changed the way the uid parameter is handled. If it is not a number, null is sent. This makes the flattenObject of the InputTransformer JS class crash, because it does not expect null. Sending 0 instead solves the issue, but I'm not sure whether this is correct or not.