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Nobody is arguing that Go should have algebraic types and ditch zero values, so I don't know why you're harping on this point. Now -- it would be somewhat nice

by cyphar 8y ago

Nobody is arguing that Go should have algebraic types and ditch zero values, so I don't know why you're harping on this point. Now -- it would be somewhat nice because errors would be much more reasonable to handle (the new "check" proposal is okay but still quite flawed) but you're right that it would either be far too complicated or old code wouldn't work anymore. Go has already made it's bed when it comes to nil values, but that doesn't mean that all new languages should follow suit -- because Go's nil handling isn't all sunshine and roses (nil interfaces -- for obvious reasons -- cause NPEs). As I've said, Go does nil basically as well as you can without having algebraic types. But given the semi-anecdotal evidence that I've definitely seen my fair share of NPEs in production Go code in the past 5 years, it's clear that it's not sufficient.

jchw 8y ago
I've had I believe a single NPE in Go in production for three years. It's a blip on the radar. If you are testing your code, how do you even get an NPE in production? Seriously, it should be rare. I've actually had more trouble with channels than pointers in Go. Also, if the situation is really so bad.... How come no one cares? I saw no Go 2 proposal to fix this situation, just generics, less boilerplate for error handling. But nothing about nil pointers. It's not at the top of anyone's list. Generally, people feel comfortable with nil in Go in ways they don't in JS and C. I will take that for fact even though certainly you disagree. So why do people feel more comfortable with nil in Go? Because nil is not an error. In C and JS, there are cases where nil is treated as an error. For example, getElementById returns null when it finds nothing. If you designed this API in Go, you'd instead return nil, PLUS an error (or Perhaps, a bool, if no other possible errors exist.) You can argue semantics but in Go it's generally held that if you aren't returning what the user wanted you should return an error. Exceptions to that exist but probably mostly just string manipulation functions. This convention is so strong, though, that it nearly eliminates nil pointer errors caused by edge cases. Most nil pointer errors you DO hit in Go are: 1. Set on nil map 2. Send on nil channel 3. Failing to check error The thing is, if you are writing production code, and writing tests for your production code, this shouldn't even make it to your code repository. It's virtually a non issue. Even better; in C and C++, when you hit a null pointer, you don't get an NPE. You get a segfault. Everything dies. Kaput. Go is obviously not alone in not having this issue, but it's surely worth noting that it doesn't. Go is not going to die some day because it's "not safe enough" - it's absolutely safe enough to write reliable code. The difference is, writing reliable code in Go is easy because for the most part, all you have to do is follow conventions and unit test. Same cannot be said about C and JS where you will inevitably get blindsided by sharp edges. If you are in a situation where you can't have runtime errors, it's a poor fit. I don't know personally any developers that are in this situation. If your code doesn't put lives on the line, its OK to have a runtime error. Most of your real outages will be due to other bugs, and probably more of then will be due to other people's bugs, natural disasters, human operator error, bad configuration pushes, etc. If you really think Go NPEs are even a significant portion of Go reliability issues I'm gonna need more evidence.
- cyphar 8y ago
  > If you really think Go NPEs are even a significant portion of Go reliability issues I'm gonna need more evidence. Don't get me wrong, there are many other Go reliability issues. I just don't agree with hand-waving it away by saying that "you should have tested for it". I'm very in favour of testing (umoci is arguably the most rigorously-tested container image format tool, and it's written in Go) but I think that tests shouldn't be used as the solution for safety problems. The logical conclusion of such a view is that any language can be reasonably safe if you have enough tests -- and while this is true (just look at SQLite) it's hardly practical to replicate the degree of testing that SQLite does for every C project. In order for everyone to benefit, safety needs to be built in (and Go does have a lot of safety built in). > Go is not going to die some day because it's "not safe enough" You keep refuting claims I never made...
  - jchw 8y ago
    The very first post I made in this thread was that I believe that this claim, that null is the biggest mistake in computer science, is way overblown. To this point, I bring up Go because Go is an example of a language where NPEs are basically a non-issue. There's not much to say there, if we still disagree on this point I'm not getting anywhere and I'm just going to give up. Following that logic, though, it feels inappropriate that null pointers have this ridiculous stigma compared to other runtime errors. Would anyone care about Rust if it's only promise were to get rid of null pointer errors? I'd argue if rust still had NPEs but effectively solved concurrency issues it would be exactly as popular today. I'm not claiming there's no value in alternatives to null. I am absolutely disputing the idea that null is the biggest mistake in computer science. Full stop, absolutely unconvinced. I can think of a lot of things I'd consider much worse. I still prefer more runtime safety over less, but there is a balance to be had too.

by cyphar 8y ago

jchw 8y ago

I've had I believe a single NPE in Go in production for three years. It's a blip on the radar. If you are testing your code, how do you even get an NPE in production? Seriously, it should be rare. I've actually had more trouble with channels than pointers in Go. Also, if the situation is really so bad.... How come no one cares? I saw no Go 2 proposal to fix this situation, just generics, less boilerplate for error handling. But nothing about nil pointers. It's not at the top of anyone's list. Generally, people feel comfortable with nil in Go in ways they don't in JS and C. I will take that for fact even though certainly you disagree. So why do people feel more comfortable with nil in Go? Because nil is not an error. In C and JS, there are cases where nil is treated as an error. For example, getElementById returns null when it finds nothing. If you designed this API in Go, you'd instead return nil, PLUS an error (or Perhaps, a bool, if no other possible errors exist.) You can argue semantics but in Go it's generally held that if you aren't returning what the user wanted you should return an error. Exceptions to that exist but probably mostly just string manipulation functions. This convention is so strong, though, that it nearly eliminates nil pointer errors caused by edge cases. Most nil pointer errors you DO hit in Go are: 1. Set on nil map 2. Send on nil channel 3. Failing to check error The thing is, if you are writing production code, and writing tests for your production code, this shouldn't even make it to your code repository. It's virtually a non issue. Even better; in C and C++, when you hit a null pointer, you don't get an NPE. You get a segfault. Everything dies. Kaput. Go is obviously not alone in not having this issue, but it's surely worth noting that it doesn't. Go is not going to die some day because it's "not safe enough" - it's absolutely safe enough to write reliable code. The difference is, writing reliable code in Go is easy because for the most part, all you have to do is follow conventions and unit test. Same cannot be said about C and JS where you will inevitably get blindsided by sharp edges. If you are in a situation where you can't have runtime errors, it's a poor fit. I don't know personally any developers that are in this situation. If your code doesn't put lives on the line, its OK to have a runtime error. Most of your real outages will be due to other bugs, and probably more of then will be due to other people's bugs, natural disasters, human operator error, bad configuration pushes, etc. If you really think Go NPEs are even a significant portion of Go reliability issues I'm gonna need more evidence.

cyphar 8y ago
> If you really think Go NPEs are even a significant portion of Go reliability issues I'm gonna need more evidence. Don't get me wrong, there are many other Go reliability issues. I just don't agree with hand-waving it away by saying that "you should have tested for it". I'm very in favour of testing (umoci is arguably the most rigorously-tested container image format tool, and it's written in Go) but I think that tests shouldn't be used as the solution for safety problems. The logical conclusion of such a view is that any language can be reasonably safe if you have enough tests -- and while this is true (just look at SQLite) it's hardly practical to replicate the degree of testing that SQLite does for every C project. In order for everyone to benefit, safety needs to be built in (and Go does have a lot of safety built in). > Go is not going to die some day because it's "not safe enough" You keep refuting claims I never made...
- jchw 8y ago
  The very first post I made in this thread was that I believe that this claim, that null is the biggest mistake in computer science, is way overblown. To this point, I bring up Go because Go is an example of a language where NPEs are basically a non-issue. There's not much to say there, if we still disagree on this point I'm not getting anywhere and I'm just going to give up. Following that logic, though, it feels inappropriate that null pointers have this ridiculous stigma compared to other runtime errors. Would anyone care about Rust if it's only promise were to get rid of null pointer errors? I'd argue if rust still had NPEs but effectively solved concurrency issues it would be exactly as popular today. I'm not claiming there's no value in alternatives to null. I am absolutely disputing the idea that null is the biggest mistake in computer science. Full stop, absolutely unconvinced. I can think of a lot of things I'd consider much worse. I still prefer more runtime safety over less, but there is a balance to be had too.