net/http: Host Header must not be deleted from http.Request.Header

[torikki-tou]

Go version

go version go1.22.0 darwin/arm64

Output of go env in your module/workspace:

GO111MODULE='on'
GOARCH='arm64'
GOBIN=''
GOCACHE='/Users/torikki/Library/Caches/go-build'
GOENV='/Users/torikki/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/torikki/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/torikki/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/Users/torikki/sdk/go1.22.0'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/Users/torikki/sdk/go1.22.0/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.22.0'
GCCGO='gccgo'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/Users/torikki/GolandProjects/connection-watcher/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/xz/tlwsgxjj4tl8s8v729j6w74w0000gn/T/go-build1614244256=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

I wanted to get Host header directly from http.Request.Header but eventually found out that it is accessible only from http.Request.Host. Why is that? Would be nice to have strait access

What did you see happen?

Host header accessible only from http.Request.Host where it might be mixed with data from URL or HTTP/2 :authority header. I need Host header unchanged

What did you expect to see?

Get Host header accessible from http.Request.Header

[seankhliao]

Duplicate of #13134

[torikki-tou]

@seankhliao I strongly disagree with what @bradfitz said there, but issue is frozen. I don't think not removing Host header (e.g. adding it) is an incompatible change. Even if it is, we could discuss adding some kind of optional parameter for that.

We have to at least agree that mandatory removal something from headers is not a good thing.