Top 50 Go Mistakes and How to Avoid Them

Go prevents common mistakes by using GODEBUG settings to opt-out of breaking changes or revert to older behaviors when upgrading toolchains. You can control specific behaviors like disabling HTTP/2 or allowing panic(nil) by setting the GODEBUG environment variable or adding //go:debug directives to your source files.

export GODEBUG=http2client=0,panicnil=1

Alternatively, add these directives to your go.mod (Go 1.23+) or source files:

//go:debug http2client=0
//go:debug panicnil=1

Verify the active settings with:

go list -f '{{.DefaultGODEBUG}}' ./my/package

GODEBUG is a safety switch that lets you tell Go to behave like an older version when a new update breaks your code. Think of it like a compatibility mode on a video game that lets you play with old controllers on a new console. You use it when you upgrade Go and suddenly your program stops working due to a security fix or behavior change.