What Is the Go 1 Compatibility Promise

The Go 1 Compatibility Promise ensures valid Go 1 code compiles and runs across future Go 1 releases, with GODEBUG allowing opt-outs for specific behavioral changes.

The Go 1 Compatibility Promise guarantees that valid Go 1 code will continue to compile and run with future Go 1 releases without modification. While the language spec is frozen, the standard library can change behavior to fix bugs or security issues, which may break code relying on those specific behaviors. You can control these changes using the GODEBUG environment variable or //go:debug directives in your source code to opt back into older behavior when necessary.

export GODEBUG=http2client=0,http2server=0

Alternatively, add directives to your go.mod or source files:

//go:debug panicnil=1

The Go 1 Compatibility Promise means your Go code won't break just because you update the Go version. It's like a guarantee that the rules of the game won't change unexpectedly. However, if a bug is fixed that your code accidentally relied on, you might need to use a special switch to tell the new version to act like the old one.