net/http: GET request with http.NoBody fails on js/wasm

[tarndt]

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

$ go version
go version go1.13.4 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

GOARCH=wasm GOOS=js running on Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:71.0) Gecko/20100101 Firefox/71.0

What did you do?

I executed code that makes a HTTP GET request using net/http facilities and it failed with the following error:

Fail:  Get https://localhost:8443/v1/endpoint: net/http: fetch() failed: <object>

I then added js.Global().Get("console").Call("log", args[0]) on line 160 of roundtrip_js.go and observed:

TypeError: "HEAD or GET Request cannot have a body."
    valueCall https://localhost:8443/wasm_exec.js:327
    run https://localhost:8443/wasm_exec.js:475
    <anonymous> https://localhost:8443/:9

I then changed the body of the request created from http.NoBody to nil and observed a successful request being made:

• Fails: req, err := http.NewRequest(http.MethodGet, URL, http.NoBody)
• Succeeds: req, err := http.NewRequest(http.MethodGet, URL, nil)

P.S. In roundtrip_js.go and the similar stdlib JavaScript platform code, if existing error reporting code such as:

err := fmt.Errorf("net/http: fetch() failed: %s", args[0].String())

is replaced with:

err := fmt.Errorf("net/http: fetch() failed: %s", js.Error{args[0]})

the output changes from:

net/http: fetch() failed: <object>

To

net/http: fetch() failed: JavaScript error: HEAD or GET Request cannot have a body.

which is substantially more helpful and perhaps warrants another issue. 😸

What did you expect to see?

Success. I expect nil and http.NoBody to function identically with respect to client `*http.Request``'s.

What did you see instead?

Failure, GET requests under GOARCH=wasm GOOS=js fail when the request body is http.NoBody rather than nil.

[agnivade]

This is fixed now: 7bfac4c#diff-e85f2dbad3447c4267e815cc9d014e69.

[tarndt]

@agnivade I see the logging was improved, but that diff does look to make any changes that would fix request with http.NoBody from failing when nil succeeds (the primary issue). Was that changed in another diff?

[agnivade]

Oh my apologies, I somehow thought that the issue was about logging. Reopening.

[gopherbot]

Change https://golang.org/cl/237758 mentions this issue: net/http: avoid setting body when NoBody is set for js/wasm