crypto/tls: client gets nondescriptive EOF error if server stops connection after client hello

[sding3]

What version of Go are you using (go version)?

$ go version
go version go1.15.1 linux/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/shang/.cache/go-build"
GOENV="/home/shang/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/shang/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/shang/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/shang/go/src/go/src/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build665899226=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Made HTTPS request against a bad server that was terminating connections upon seeing TLS client hello.

Click to expand sample bad server

package main

import (
	"net"
)

func main() {
	l, err := net.Listen("tcp", "localhost:1234")
	panicOnErr(err)
	defer l.Close()

	for {
		conn, err := l.Accept()
		panicOnErr(err)
		conn.Close()
	}
}

func panicOnErr(e error) {
	if e != nil {
		panic(e)
	}
}

What did you expect to see?

Expected to see some contextual information on the error indicating issue with tls or better yet tls handshake. For comparision, curl, in this case, emitts curl: (35) OpenSSL SSL_connect: SSL_ERROR_SYSCALL

Most errors from the crypto/tls package prefix their errors with additional context in the form of tls: {extra info} ... in a helpful way, but this EOF error here appears to be an exception.

What did you see instead?

Got a nondescriptive EOF error.

---

edit: reformat markdown codeblock

[networkimprov]

cc @FiloSottile

[gopherbot]

Change https://golang.org/cl/299449 mentions this issue: crypto/tls: add error context to handshake error

[sding3]

This appears to be a duplicate of #19874, and #13523.

I'm closing this one out.