[ffsm8]

> why not? what's the difference between those two categories, mentioned in your last two sentences, as far as this argument about illegal states is concerned? not clear to me.

I kinda began my comment with that reason: The difficulty entirely depends on whether discarding the occasional invalid write is possible. If you can simply return an error and ignore the write/transaction, you're golden.

If you can't, it becomes incredibly complicated

[namaria]

Shouldn't an unrepresentable bad state not even have been proposed as a write tho? I mean the way I understand it, if something is trying to write a bad state somewhere, it is being represented somehow isn't it?

[ffsm8]

No, because you almost never have full data autonomy in corporate contexts. And the microservice arichtecures don't make this more robust either.

I.e. a transaction will have a matching transaction in another corporations/banks system, even if you don't have a distributed monolith unlike everyone else.

[namaria]

I see, well, that is a good point. What is the point of any architectural consideration when you are forced to ingest garbage because others have not made any effort to properly architect their systems. Maybe a strong reason why worse is better in practice.