[rubyn00bie]

Thanks for the info!

And... Woah. That's kind of horrifying to me (though I totally get the explicitness of it)... does this just mean liberal amounts of: thing != nil everywhere? Or is the rest of the memory management I guess, uhh.., good/magical enough you don't have to worry about it constantly in calls further down the stack if you've checked it once? Or are you always feeding the nil check beast?

[malisper]

> does this just mean liberal amounts of: thing != nil everywhere

Yes, it does. Whenever you call a function that can possibly fail, you are supposed to add:

  if err != nil {
      return err
  }

You can think of it as unwinding the stack by hand. That's why a lot of people complain about Go error handling so much. That and a lack of generics. Looking at some code I've written, about 15-20% of the lines in a file are responsible for error handling.

> Or is the rest of the memory management I guess, uhh.., good/magical enough you don't have to worry about it constantly in calls further down the stack if you've checked it once?

I don't quite understand the question here. Are you asking about a performance impact of having nil checks everywhere? If I had to guess, I would think there's a negligible performance impact because the branch predictor will always predict the happy case. As for memory concerns, as long as you are in the happy case and returning nil, no memory needs to be allocated. It's the same reason null doesn't require any memory allocation in other languages.

[weberc2]

> Yes, it does. Whenever you call a function that can possibly fail, you are supposed to add: if err != nil { return err }

I don’t think that’s what the parent meant by his question. He was asking if you have to add runtime checks all over to make sure any reference type isn’t nil; no, you don’t—you only add the checks for those for which nil is a valid state in the program (such as errors). If it’s an invalid state, it will panic because it’s an exceptional circumstance—a programmer error. This isn’t a defense of nil; only a clarification about how nil is dealt with. With this context, the rest of his question (the part you didn’t understand) becomes clearer.