Go 1 (2012-03-28)

Go 1 is the first formal stable release of the Go language, released on March 28, 2012. It marks the maturity of the Go language and brings an extremely important compatibility promise as well as a unified toolchain experience.

Major Changes

Language

• rune Type: Introduced rune as an alias for int32, used to represent Unicode code points.
• error Interface: Introduced the built-in error interface type, replacing the previous os.Error, forming a unified error handling contract.
• append Supports Strings: append can now directly append strings to []byte slices, simplifying byte sequence operations.
• delete Built-in Function: Provided delete(m, k) for deleting elements from a map.
• Structs and Arrays Comparable: They now support ==/!= and can be used as map keys, improving data structure composition capabilities.
• Composite Literal Simplification: Pointer type elements in composite literals can omit type declarations.
• Map Iteration Order: Explicitly defined as random order, encouraging robust traversal logic.
• close Check: Prohibited closing receive-only channels to avoid runtime panics.

Toolchain

• go Command: A unified command-line tool integrating functions like get/build/install/test/doc, automatically handling dependencies based on source code imports, relying on the GOPATH structure (src/pkg/bin).
• cgo: Strengthened C language interoperability support, improving system call usability.
• go fix: Includes a migration tool to automatically convert old version code to the Go 1 specification.
• gofmt: Further standardized code style, becoming an indispensable formatting solution in the Go ecosystem.

Runtime

• Compatibility Promise: Besides introducing language and tool changes, the core of Go 1 is the compatibility guarantee for the Go 1.x lifecycle: as long as the code complies with the Go 1 specification, it will continue to compile and run, with very few exceptions not affecting mainstream application stability.

Standard Library

• Package Path Reorganization: Multiple packages migrated to form a more reasonable hierarchy: http→net/http, template→text/template, exec→os/exec, utf8→unicode/utf8.
• os.Error Removal: Replaced by the error interface and the errors package.
• syscall Errors: Unified to return the error interface.
• time Package Rewrite: Introduced time.Time and time.Duration, providing nanosecond precision.
• os.FileInfo Becomes Interface: Abstracted file information access methods, increasing extensibility.
• regexp Package Rewrite: Adopted RE2 syntax, ensuring linear time execution.

References

For more details, please refer to the official release notes: Go 1 Release Notes