[skydhash]

If such an error happens, that would be a compiler bug. Why? Because I usually do checks against the length of the array or have it done as part of the standard functions like `map`. I don't write such assumptions unless I'm really sure about the statements, and even then I don't.

[tosapple]

How does one defend against cosmic rays?

Keep two copies or three like RAID?

Edit: ECC ram helps for sure, but what else?

[well_ackshually]

>How does one defend against cosmic rays?

Unless you are in the extremely small minority of people who would actually be affected by it (in which case your company would already have bought ECC ram and made you work with three isolated processes that need to agree to proceed): you don't. You eat shit, crash and restart.

[tosapple]

Well, bitflip errors are more of a vulnerability for longer lived values. This could effect fukushima style robots or even medical equipment. ECC implemented outside of ram would save vs triplicate but it was just a question related to the-above idea of an array access being assumed as in+bounds. Thank you.

[JonChesterfield]

You run equivalent or equal calculations simultaneously on N computers and take majority wins, aircraft control or distributed filesystem style.

[LegionMammal978]

> or have it done as part of the standard functions like `map`.

Which are all well and good when they are applicable, which is not always 100% of the time.

> Because I usually do checks against the length of the array

And what do you have your code do if such "checks" fail? Throw an assertion error? Which is my whole point, I'm advocating in favor of sanity-check exceptions.

Or does calling them "checks" instead of "assumptions" magically make them less brittle from surrounding code changes?

[skydhash]

A comment have no semantic value to the code. Having code that check for stuff is different from writing comments as they are executed by the machine. Not read by other humans.

[LegionMammal978]

Of course you should put down a real assertion when you have a condition that can be cheaply checked (or even an assert(false) when the language syntax dictates an unreachable path). I'm not trying to argue against that, and I don't think anyone else here is either.

I was mainly responding to TFA, which states "How many times did you leave a comment on some branch of code stating 'this CANNOT happen' and thrown an exception" (emphasis mine), i.e., an assertion error alongside the comment. The author argues that you should use error values rather than exceptions. But for such sanity checks, there's typically no useful way to handle such an error value.

[awesome_dude]

Do you really have code that's

if array.Len > 2 { X = Y[1] }

For every CRUD to that array?

That seems... not ideal

[skydhash]

Yes. Unless there’s some statement earlier that verify that the array has 2 items. It’s quick to do, so why not do it?