the author is misusing the "leaky abstraction" idea. in the section "what's in a leak" a rather muddy argument is made that a leak is that which forces you to bend your program to accommodate it. so `leak => accommodation`.

then it immediately conflates the need for that accommodation (difficulty of calling one type of code with another) with "leakiness". so essentially "calling blocking => more accommodation" (e.g. from event loops that shouldn't block).

- that's logically incorrect, even in the author's own argument (A => B, B, therefore A is the affirming the consequent fallacy).

- that's not what a "leaky abstraction" is. not everything that doesn't fit perfectly or is hard is due a "leaky abstraction". rather it's when the simplistic model (abstraction) doesn't always hold in visible ways.

a "leaky abstraction" to "blocking" code might be if code didn't actually block or execute in-order in all situations. until you get to things like spinlocks and memory barriers this doesn't happen. but that's more a leak caused by naively extending the abstraction to multi-core/multi-thread use, not the abstraction of blocking code itself.

i love the passion for `async` from this fellow, but i think he's reacting to "async is a leaky abstraction" as if it were a slur or insult, while misunderstanding what it means. then replies with a "oh yeah, well your construct is twice as leaky" retort.