zlacker

> Congratulations, nobody is going to sneakily update an object on you

I've seen Heisenbugs where some random code calls a setter on an object in a shared memory cache. The setter call was for local logic - so immutable update would've saved the day. It had real world impact too: We ordered a rack with a European plug to an American data center (I think a human in the loop caught it thankfully).

Also, how often do you even use mutability really? Like .. for what? Logic is easier to express with expressions than a Rube Goldberg loop mutating state imo.

>>whatev+(OP)
>how many Heisenbugs

I suspect, given the real, actual measurements, the number of difficult to deal with bugs is pretty consistent between immutability and mutability. Actual measurements does not support claims of “easier to reason about”, or “reduced bugs”.

>how often do you use mutability

Whenever something should change and I don’t specifically need functionality that immutability might provide (literally 99.99999999% of every state change).

>>wredue+m32
I'm just confused as to what you need mutability for exactly? I get needing it for communicating between processes (STM has you covered there). But for "normal" code that is doing pure logic, what is the benefit of using mutability?

Immutability has some big advantages for pure logic, such as allowing containers to be treated as values the same as numbers. And efficient immutable data structures of all kinds are commonplace now.