You started with "In no language has a variable assignment ever stopped execution", and now you're saying "The assignment operator is not supposed to have side-effects". location.href is a counterexample, and there are many counterexamples throughout various tools and languages and libraries. Deciding how you think things should work does not affect how things do work, and it's important to understand the latter. (I do agree it's bad practice, but it happens and people do not always fully control the environments they must work with.)

And given that location.href does have a side effect, it's not unreasonable for someone to have assumed that that side effect was immediate rather than asynchronous.

That said, if you don't like working with such languages, that's all the more reason to select languages where that doesn't happen, which comes back to the point made in the article.

Assignment is by definition a side effect.

This whole discussion is completely off kilter by all parties because setting the variable doesn't terminate the script--that's the bug; it simply sets the variable (that is, it sets a property in a globally accessible structure). Rather, some time later the new page is loaded from the variable that was set.

Aside from that, your comments are riddled with goalpost moving and other unpleasant fallacies and logic errors.

FWIW I grew up in the days (well, actually I was already an adult who had been programming for a decade) when storing values in the I/O page of PDP-11 memory directly changed the hardware devices that mapped their operation registers to those memory addresses. That was the main reason for the C `volatile` keyword.

> The assignment operator is not supposed to have side-effects,

Memory mapped I/O disagrees with this. Writing a value can trigger all sorts of things.

assignments are side effects, even more so when they are done through a setter on an object / class instance