Go 1 20

Overview

Go 1.20 introduces Profile-Guided Optimization (PGO) as a preview feature, along with coverage improvements and better error handling. Released in February 2023, this release focuses on performance and testing capabilities.

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flowchart TD
    A[Go 1.20 Release<br/>February 2023] --> B[PGO Support<br/>Profile-Guided Optimization]
    A --> C[Coverage Improvements<br/>Better Testing]
    A --> D[Error Wrapping<br/>Enhanced Errors]
    A --> E[Slice to Array<br/>Conversions]

    B --> B1[Build Optimization<br/>Production Profiles]
    B --> B2[Performance Gains<br/>5-15% Faster]

    C --> C1[Coverage for Tests<br/>Detailed Reports]

    D --> D1[errors.Join<br/>Multiple Errors]

    E --> E1[Zero-Copy Conversion<br/>[]byte to [N]byte]

    style A fill:#0173B2,color:#fff
    style B fill:#DE8F05,color:#fff
    style C fill:#029E73,color:#fff
    style D fill:#CC78BC,color:#fff
    style E fill:#0173B2,color:#fff

Key Features

Profile-Guided Optimization (Preview)

Optimize builds using runtime profiles:

# Collect profile
go test -cpuprofile=cpu.prof

# Build with PGO
go build -pgo=cpu.prof

Enhanced Error Handling

Join multiple errors:

err1 := errors.New("first error")
err2 := errors.New("second error")
combined := errors.Join(err1, err2)

Slice to Array Conversions

Zero-copy conversions:

slice := []byte("hello")
array := [5]byte(slice)  // Conversion supported

Breaking Changes

Consult the official Go 1.20 documentation for detailed breaking changes and migration guidance.

References


Last Updated: 2026-02-04 Go Version: 1.18+ (baseline), 1.25.x (latest stable)

Last updated