Skip to main content
Version: 2.9.x(Latest)

Go 1.22 (2024-02-06)

Go 1.22 was released in February 2024, primarily addressing the long-standing loop variable issue and enhancing HTTP routing capabilities.

Major Changes​

Language​

  • Loop Variable Scope: Variables declared in a for loop are now created as new instances for each iteration. This solves the common issue of closures capturing loop variables.
  • Range over integers: for range now supports integers, e.g., for i := range 10 will iterate from 0 to 9.
  • Range-over-function (Preview): Introduced preview support for range-over-function iterators (enabled via GOEXPERIMENT=rangefunc).

Toolchain​

  • Go Command:
    • Workspaces now support vendor directories.
    • go get is no longer supported in non-module legacy GOPATH mode.
    • go test -cover can now report coverage for packages without test files (as 0%).
  • Trace: The trace tool's Web UI has been updated, improving readability and thread-oriented views.
  • Vet:
    • Adapted to the new loop variable semantics, no longer reporting loop variable references that are no longer issues.
    • Added checks: missing values after append, direct calls to time.Since in defer, mismatched key-value pairs in log/slog.

Runtime​

  • Performance Optimization: The runtime now keeps type-based GC metadata near heap objects, improving CPU performance (1-3%) and reducing memory overhead.
  • PGO Enhancements: PGO builds can now devirtualize more calls, with performance improvements typically between 2-14%.
  • Inlining Enhancements (Preview): Introduced a preview of an enhanced inlining phase (enabled via GOEXPERIMENT=newinliner).

Standard Library​

  • math/rand/v2: Introduced the math/rand/v2 package, providing faster and more standard random number generators (such as ChaCha8, PCG) and cleaning up old APIs.
  • net/http Routing Enhancements: http.ServeMux now supports method matching (e.g., GET /items) and wildcards (e.g., /items/{id}, /files/{path...}).
  • go/version: Added go/version package for parsing and comparing Go version strings.
  • slices: Added Concat function for concatenating slices; functions that shrink slices like Delete now zero out the deleted elements.
  • cmp: Added Or function, returning the first non-zero value in a sequence.
  • database/sql: Added Null[T] type for scanning nullable columns of any column type.

References​

For more details, please refer to the official release notes: Go 1.22 Release Notes