It's Postel's Law being bad advice yet again. No, you should not be liberal in what you accept, because being liberal in what you accept causes even more malformed data to appear in the ecosystem.
For me the revelatory moment was in mid-00s, when everyone screamed anathema at XHTML, saying it was bad because it required people to write well-formed documents, when everyone just wanted to slap random tags and somehow have that steaming mess to still work.
There must me some sort of law that says in tech the crudest pile of hacks wins over any formally elegant solution every single time those hacks lets one do something that requires extra effort otherwise, even if it works only by wildest chance.
The biggest objection I and many others had at the time was that writing xhtml forced one to deal with hell that is xml namespaces, which many tools at the time barely supported
> bad advice ... being liberal in what you accept causes even more malformed data to appear in the ecosystem.
This is one perspective. Another is to be robust and resilient. Resiliency is a hallmark of good engineering. I get the sense you have not worked on server-side software that has thousands or millions of different clients.
Postel's Law should be called the "Hardness Principle", not the "Robustness Principle". Much like how hardening a metal makes it take more force to break, but results in it being brittle & failing catastrophically when it does, so Postel's law makes systems harder to break initially, but results in more damage when they do fail. It also makes the system harder to maintain, thus adding a pun to the name.
Where do you draw the line? Usually there's exactly 1 intended, standard way of communicating with another system while there's are infinite opportunities to deviate from that standard and infinite opportunities for the other party to try to guess what you really meant. This results in a combinatorial explosion unintended behaviors that lead to bugs and critical security vulnerabilities.
I absolutely have. And I've never modified a server to accept bullshit from an incorrect client. I have, on the other hand, told several people how to fix their clients when they complain it doesn't work with my service. I actually rather enjoy improving the ecosystem, even if it's not strictly my job. It's better for everyone.
For me the revelatory moment was in mid-00s, when everyone screamed anathema at XHTML, saying it was bad because it required people to write well-formed documents, when everyone just wanted to slap random tags and somehow have that steaming mess to still work.
There must me some sort of law that says in tech the crudest pile of hacks wins over any formally elegant solution every single time those hacks lets one do something that requires extra effort otherwise, even if it works only by wildest chance.