h2nilderef.go

package main

import (
	"fmt"
	"net/http"
	"net/url"
)

func request(url_ string) {
	req, err := http.NewRequest("HEAD", url_, nil)
	if err != nil {
		panic(err)
	}
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	res.Body.Close()
	fmt.Println(url_, res.Status)
}

func main() {
	okURL, err := url.Parse("https://www.gkogan.co/blog/dont-design-emails/")
	if err != nil {
		panic(err)
	}

	badURL, err := url.Parse("https://www.gkogan.co/blog/dont-design-emails")
	if err != nil {
		panic(err)
	}

	fmt.Printf("OK URL:\n%#v\n\n", okURL)
	fmt.Printf("Bad URL:\n%#v\n\n", badURL)

	request(okURL.String())
	request(badURL.String())
}

output.txt

$ go run h2nilderef.go                                                                                                                                                                                                                                                                                                               master
OK URL:
&url.URL{Scheme:"https", Opaque:"", User:(*url.Userinfo)(nil), Host:"www.gkogan.co", Path:"/blog/dont-design-emails/", RawPath:"", ForceQuery:false, RawQuery:"", Fragment:""}

Bad URL:
&url.URL{Scheme:"https", Opaque:"", User:(*url.Userinfo)(nil), Host:"www.gkogan.co", Path:"/blog/dont-design-emails", RawPath:"", ForceQuery:false, RawQuery:"", Fragment:""}

https://www.gkogan.co/blog/dont-design-emails/ 200 OK
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x30 pc=0x5bafc0]

goroutine 35 [running]:
net/http.(*http2pipe).Write(0xc4200ba168, 0xc4204ca000, 0x29, 0x87, 0x0, 0x0, 0x0)
        /opt/go/src/net/http/h2_bundle.go:3661 +0x100
net/http.(*http2clientConnReadLoop).processData(0xc4204c9fb0, 0xc42007ce70, 0xc42007ce70, 0x0)
        /opt/go/src/net/http/h2_bundle.go:8259 +0x2ac
net/http.(*http2clientConnReadLoop).run(0xc4204c9fb0, 0x67ec80, 0xc420461fb0)
        /opt/go/src/net/http/h2_bundle.go:7896 +0x54f
net/http.(*http2ClientConn).readLoop(0xc42007eb60)
        /opt/go/src/net/http/h2_bundle.go:7788 +0x9d
created by net/http.(*http2Transport).newClientConn
        /opt/go/src/net/http/h2_bundle.go:7053 +0x6b9
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x5df730]

goroutine 1 [running]:
net/http.(*http2ClientConn).RoundTrip.func1(0x0, 0x0, 0x0, 0x0, 0x18, 0x0)
        /opt/go/src/net/http/h2_bundle.go:7324 +0x240
net/http.(*http2ClientConn).RoundTrip(0xc42007eb60, 0xc420122000, 0x0, 0x0, 0x0)
        /opt/go/src/net/http/h2_bundle.go:7356 +0xe80
net/http.(*http2Transport).RoundTripOpt(0xc420084230, 0xc420122000, 0xc42014c100, 0xc420053848, 0x40a860, 0xffffffffffffffff)
        /opt/go/src/net/http/h2_bundle.go:6858 +0x145
net/http.(*http2Transport).RoundTrip(0xc420084230, 0xc420122000, 0x592601, 0xc420016120, 0xc420053a78)
        /opt/go/src/net/http/h2_bundle.go:6820 +0x3a
net/http.http2noDialH2RoundTripper.RoundTrip(0xc420084230, 0xc420122000, 0xc4203bc360, 0x5, 0xc420098aa8)
        /opt/go/src/net/http/h2_bundle.go:990 +0x39
net/http.(*Transport).RoundTrip(0x7b6420, 0xc420122000, 0x7b6420, 0x0, 0x0)
        /opt/go/src/net/http/transport.go:371 +0xd47
net/http.send(0xc420122000, 0x784c20, 0x7b6420, 0x0, 0x0, 0x0, 0xc4202400c0, 0x7d9738, 0x7848e0, 0x2)
        /opt/go/src/net/http/client.go:249 +0x1a9
net/http.(*Client).send(0x7b9ee0, 0xc420122000, 0x0, 0x0, 0x0, 0xc4202400c0, 0x1, 0x2, 0x0)
        /opt/go/src/net/http/client.go:173 +0xfd
net/http.(*Client).Do(0x7b9ee0, 0xc420102200, 0xc4203bc360, 0x2d, 0x0)
        /opt/go/src/net/http/client.go:602 +0x28d
main.request(0xc4203bc360, 0x2d)
        /home/cgt/dev/go/src/h2nilderef/h2nilderef.go:14 +0xaf
main.main()
        /home/cgt/dev/go/src/h2nilderef/h2nilderef.go:37 +0x1a1
exit status 2
$ go run h2nilderef.go                                                                                                                                                                                                                                                                                                             1 master
OK URL:
&url.URL{Scheme:"https", Opaque:"", User:(*url.Userinfo)(nil), Host:"www.gkogan.co", Path:"/blog/dont-design-emails/", RawPath:"", ForceQuery:false, RawQuery:"", Fragment:""}

Bad URL:
&url.URL{Scheme:"https", Opaque:"", User:(*url.Userinfo)(nil), Host:"www.gkogan.co", Path:"/blog/dont-design-emails", RawPath:"", ForceQuery:false, RawQuery:"", Fragment:""}

https://www.gkogan.co/blog/dont-design-emails/ 200 OK
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x30 pc=0x5bafc0]

goroutine 35 [running]:
net/http.(*http2pipe).Write(0xc4203962a8, 0xc4203f8000, 0x29, 0x87, 0x0, 0x0, 0x0)
        /opt/go/src/net/http/h2_bundle.go:3661 +0x100
net/http.(*http2clientConnReadLoop).processData(0xc4203f7fb0, 0xc42049a360, 0xc42049a360, 0x0)
        /opt/go/src/net/http/h2_bundle.go:8259 +0x2ac
net/http.(*http2clientConnReadLoop).run(0xc4203f7fb0, 0x67ec80, 0xc4204967b0)
        /opt/go/src/net/http/h2_bundle.go:7896 +0x54f
net/http.(*http2ClientConn).readLoop(0xc42007eb60)
        /opt/go/src/net/http/h2_bundle.go:7788 +0x9d
created by net/http.(*http2Transport).newClientConn
        /opt/go/src/net/http/h2_bundle.go:7053 +0x6b9
exit status 2