TL;DR. golang.org/x/net/idna.Lookup.ToASCII runs UTS-46 NFKC mapping 0-9. A pre-IDNA net.ParseIP check rejects the NO_PROXY lists, TLS-SNI routers, and cookie-domain validators that TrimRight + ParseAddr golang.org/x/net/http/httpproxy, the canonical safe pattern, and two I ran into this one while writing a Go HTTP client for a private project. I idna.Lookup.ToASCII canonicalising the host The sha
You have probably seen a file named “go.sum” in almost every Go project you have worked on. You may have even seen it change every time you run “go mod tidy”. But do you actually know what it does? It is one of those files that works silently in the background, and some developers never stop to think about it. The “go.sum” file is one of those files you never really interact with directly, but it