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Let's Play with Golang 1.18

omissis
April 27, 2022

Let's Play with Golang 1.18

Slides of the Turin Golang Meetup

omissis

April 27, 2022
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  1. Let's play with Go 1.18!
    Claudio Beatrice - April 27th, 2022
    Having fun fun fun 🕺 with


    Generics, Fuzzing and Workspace Mode

    View Slide

  2. Introducing Go 1.18
    This is the best iPhone we’ve ever made
    • It was released on Mar 15th, 2022 , seven months after Go 1.17 📆


    • It’s one of the major changes in the language ever done 🚛


    • It packs a TON of new features, plus library and tooling improvements


    • Generics 㿂


    • Fuzzing 🎛


    • Workspace mode 🗃


    • Sane packages for sorting stuff! 🥇


    • It keeps the Compatibility Promise, as usual 😎

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  3. Generics
    One does not simply write speci
    f
    ic code
    • Write functions or types that are written work with any of a set of types
    provided by the calling code


    • Generic code is independent of the speci
    f
    ic types being used


    • Generics adds three new big things to the language:


    • Type parameters


    • Type inference


    • Interface types as sets of types

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  4. Generics
    Type Parameters
    func Min[T constraints.Ordered](x, y T) T {
    func Min(x, y int) int {
    As opposed to the an equivalent (for ints) monomorphic version

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  5. Generics
    Type Inference
    x := Min[int](2, 3)
    x := Min(2, 3)
    Could be simpli
    f
    ied to

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  6. Generics
    Type Sets
    package constraints
    type Ordered interface {
    Integer|Float|~string
    }
    Interfaces may now be used as type constraints,


    and they support union of different types.

    View Slide

  7. Generics
    Bracket beats chevron
    package main
    import "fmt"
    import "golang.org/x/exp/constraints"
    func Min[T constraints.Ordered](x, y T) T {
    if x < y {
    return x
    }
    return y
    }
    func main() {
    fmt.Println(Min[int](2, 3))
    fmt.Println(Min[float32](2.5, 2.6))
    }

    View Slide

  8. Generics
    Chevron cuts paper
    package main
    import "fmt"
    func Min(x, y int) int {
    if x < y {
    return x
    }
    return y
    }
    func main() {
    fmt.Println(Min(2, 3))
    fmt.Println(Min(2.5, 2.6)) // Error!
    }

    View Slide

  9. Fuzzing
    Get cover!
    Fuzzing is a type of automated testing which continuously manipulates
    inputs to a program to
    f
    ind bugs.


    Good for
    f
    inding edge cases: it’s an extremely valuable feat whenever
    security is concerned, and still very valuable to hunt down hard-to-
    f
    ind
    bugs.

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  10. Fuzzing
    Fuzz Anatomy 101

    View Slide

  11. Workspace mode
    It ain’t much, but it’s honest go work
    • A new, optional go.work
    f
    ile has been introduced: if present, it will set Go
    in Worskpace Mode.


    • When in Worskpace Mode, go will use the go.work
    f
    ile to determine all
    the modules to use as roots for module resolution, as opposed to having a
    single one as imposed by go.mod


    • Such Mode allows for work on multiple, independent modules at the same
    time more conveniently than it was in the past

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  12. Workspace mode
    It ain’t much, but it’s honest go work
    go 1.18
    use ../foo/bar
    use ./baz
    replace example.com/foo v1.2.3 => example.com/bar v1.4.5

    View Slide

  13. New experimental packages
    Sort like it’s 2022
    • https://pkg.go.dev/golang.org/x/exp/constraints


    • https://pkg.go.dev/golang.org/x/exp/slices


    • https://pkg.go.dev/golang.org/x/exp/maps

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  14. New networking package
    It’s a net improvement
    • New net/netip package, featuring Addr and AddrPort types


    • Compared to net.IP, netip.Addr is more memory ef
    f
    icient, immutable,
    comparable and can be used as a map key


    • Besides an IP and a port, AddrPort can also represent a CIDR pre
    f
    ix


    • Tons of new functions to work on the newly de
    f
    ined types


    • Loads of helpers for bridging with the old net.IP package

    View Slide

  15. And moar!
    Faster and furiouser, sometimes
    • More ef
    f
    icient way to pass function argument on arm64 and some amd64,
    getting up to 10% performance improvements


    • Due to generics, compile speed can get about 15% slower than go 1.17


    • Nice strings functions improvements, hello Cut()!


    • Ditto for bytes


    • Introduces the new any identi
    f
    ier as an alias for interface{}


    • Loads of other little minor changes

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  16. Bibliography
    Slides are important, but study is importanter
    • Go 1.18 Release Notes


    • Article: An Introduction to Generics


    • Article: Are Go Generics ready for Prime Time?


    • Documentation: Fuzzing


    • Reference: Go Workspaces

    View Slide

  17. Big Pizza Thanks
    There’s food in the Cloud

    View Slide

  18. Enough talk!
    Pick your poison
    https://go.dev/doc/tutorial/generics 㿂


    https://go.dev/doc/tutorial/fuzz 🎛


    https://go.dev/doc/tutorial/workspaces 🗃

    View Slide