[simple-linked-list] Add missing initialValues field

[senekor]

Templating languages that distinguish between undefined and empty list
will crash out on this missing field, or force the template author to
handle the field's absence explicitly.

[IsaacG]

This actually causes the Go generator to swap []int(nil) (a null slice) for []int{} (an empty slice) which is less idiomatic :D Now I'm debating trying to add something to the test to force things back to nil.

[senekor]

There are several other test cases with an empty initialValues, so the problem should've existed already?

Maybe off topic here, but I am curious why nil is more idiomatic :) I assume that []int{} is optimized not to cause an allocation. When I was using Go a couple years ago, "empty" and "nil" objects being different things was an unpleasant source of bugs.

[IsaacG]

There are several other test cases with an empty initialValues, so the problem should've existed already?

Yup. Though it's not a problem so much as not following accepted style.

Maybe off topic here, but I am curious why nil is more idiomatic :) I assume that []int{} is optimized not to cause an allocation. When I was using Go a couple years ago, "empty" and "nil" objects being different things was an unpleasant source of bugs.

Go encourages the "zero value" to be useable as is. You should be able to use the nil slice interchangably with the empty slice for most things in Go.

See https://google.github.io/styleguide/go/decisions#nil-slices and https://github.com/pthethanh/effective-go#declaring-empty-slices