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

$ go version
go version go1.12 linux/amd64

Does this issue reproduce with the latest release?

yes

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

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/mlesyk/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/mlesyk/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/lib/go-1.12"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go-1.12/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
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-build990918272=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Using simplest webdav server ( source here: https://gist.github.com/lesykm/e21c765331fa5af7dd00652dfe671eb5 )

1. go get golang.org/x/net/webdav
2. curl -qs https://gist.githubusercontent.com/lesykm/e21c765331fa5af7dd00652dfe671eb5/raw/e967a66d5018e2f456ead82132f412c475b59401/main.go --output main.go
3. go run main.go
4. echo '<?xml version="1.0"?><a:propfind xmlns:a="DAV:"><a:prop><a:resourcetype/></a:prop></a:propfind>' | curl -qs -X PROPFIND http://127.0.0.1:8080/ --upload-file - | xmllint --format -

What did you expect to see?

<?xml version="1.0" encoding="UTF-8"?>
<D:multistatus xmlns:D="DAV:">
  <D:response>
    <D:href>/</D:href>
    <D:propstat>
      <D:prop>
        <D:resourcetype>
          <D:collection xmlns:D="DAV:"/>
        </D:resourcetype>
      </D:prop>
      <D:status>HTTP/1.1 200 OK</D:status>
    </D:propstat>
  </D:response>
</D:multistatus>

What did you see instead?

<?xml version="1.0" encoding="UTF-8"?>
<D:multistatus xmlns:D="DAV:">
  <D:response>
    <D:href>//</D:href>
    <D:propstat>
      <D:prop>
        <D:resourcetype>
          <D:collection xmlns:D="DAV:"/>
        </D:resourcetype>
      </D:prop>
      <D:status>HTTP/1.1 200 OK</D:status>
    </D:propstat>
  </D:response>
</D:multistatus>

Difference:

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <D:multistatus xmlns:D="DAV:">
   <D:response>
-    <D:href>/</D:href>
+    <D:href>//</D:href>
     <D:propstat>
       <D:prop>
         <D:resourcetype>

Breaking change was introduced in golang/net#32

This leads to incorrect display of root directory source in different webdav clients.