assert VS CraueFormFlowBundle

This is not Java where everything is nullable by default. Use that in your favor and set dependencies correctly via constructor like this. For this to correctly work, check the empty_data callable and webmozart/assert package:

I actually do have that case, many of them. For that, I use form_data. This example is a bit old-school, statically analyzed one would be using webmozarts/assert like:

For APIs relying on array and not something like cuyz/valinor (best deserializer I have ever seen), one-liners are still good with webmozart/assert:

// https://github.com/webmozarts/assert Assert::nullOrInteger($price = $data['price'] ?? null); if ($price) { $p->setPrice($price); // we don't care about return value }

as will throw exception immediately, similar to assertion package:

What I do with the VueJS forms is using a assertion library like https://github.com/webmozarts/assert to handle the validation of the incoming data.

Exactly my point; not only Symfony has multi-step support but more importantly, any backend processing is simple using events.