Let's look at Go 1.18

Slides of the Milan Golang Meetup

Transcript

1. Let's look at Go 1.18!
   Claudio Beatrice - June 6th, 2022
   Having fun fun fun 🕺 with
   
   
   Generics, Fuzzing and Workspace Mode
   

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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. Theory and Practice
   In theory they are the same, in practice they aren't
   

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4. Generics
   One does not simply write speci
   f
   ic code
   • Write functions or types that work with any of a set of types provided by
   the calling code
   
   
   • Generic code is loosely coupled to the speci
   f
   ic types being used
   
   
   • Generics add three new, important features to the language:
   
   
   • Type parameters
   
   
   • Type inference
   
   
   • Interface types as sets of types
   
   
   • Create zero values out of generic types
   

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

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7. 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.
   

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8. 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))
   }
   

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9. 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!
   }
   

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10. Generics
    It's showtime!
    Let's have a look at some examples:
    
    
    - interfaces: https://go.dev/play/p/PrqtLSmbVMi
    
    
    - generics: https://go.dev/play/p/RCnt4xM24mS
    
    
    - gondola's lang module
    

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11. 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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12. Fuzzing
    Fuzz Anatomy 101
    

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13. Fuzzing
    Time to check gondola again
    One more thing
    

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14. 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 Workspace Mode.
    
    
    • When in Workspace 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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15. 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
    

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16. Workspace mode
    it's the last time, I swear
    Open gondola once more
    

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17. 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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18. 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
    

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19. 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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20. 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
    
    
    • Learning Go's free chapters on Generics
    

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21. Practice makes perfect
    Pick your poison
    https://go.dev/doc/tutorial/generics 㿂
    
    
    https://go.dev/doc/tutorial/fuzz 🎛
    
    
    https://go.dev/doc/tutorial/workspaces 🗃
    

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22. What about go 1.19?
    You thought it was over, huh
    • re
    f
    inements and improvements to generics
    
    
    • new unix build constraint
    
    
    • faster regex functions (~ -30% exec time)
    
    
    • faster large switch statements(int and string only)
    
    
    • more ef
    f
    icient race detector (1.5-2.0x faster, ~50%
    memory usage, unlimited goroutines)
    
    
    • lots of minor library changes, as usual
    

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23. Thanks
    And see you at the next meetup!
    

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24. Tell your friends!
    And your enemies, too
    

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