Go for C# (.NET) Developers: What Changes

Go provides GODEBUG settings to control runtime behavior and opt back into legacy behavior when upgrading toolchains. You can set these via the GODEBUG environment variable, godebug directives in go.mod/go.work, or //go:debug comments in source files.

export GODEBUG=http2client=0,panicnil=1

To set defaults in your module file (go.mod or go.work):

godebug (
    default=go1.21
    panicnil=1
)

Or in your source file before the package statement:

//go:debug panicnil=1
package main

func main() {
	// Example code
}

Verify the active settings with:

go env GODEBUG

GODEBUG acts like a set of switches that let you tell a newer version of Go to behave like an older one. This is useful when a Go update changes how a feature works and breaks your existing code. Instead of rewriting your code, you flip a switch to restore the old behavior until you are ready to update.