net/http: disable fetch on NodeJS

NodeJS 18 introduced support for the fetch API for
making HTTP requests. This broke all wasm tests
that were relying on NodeJS falling back to the fake
network implementation in net_fake.go. Disable
the fetch API on NodeJS to get tests passing.

Fixes golang#57613

Change-Id: Icb2cce6d5289d812da798e07366f8ac26b5f82cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/463976
Reviewed-by: Evan Phoenix <evan@phx.io>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

src/net/http/roundtrip_js.go

@@ -44,6 +44,12 @@ const jsFetchRedirect = "js.fetch:redirect"
 // the browser globals.
 var jsFetchMissing = js.Global().Get("fetch").IsUndefined()
 
+// jsFetchDisabled will be true if the "process" global is present.
+// We use this as an indicator that we're running in Node.js. We
+// want to disable the Fetch API in Node.js because it breaks
+// our wasm tests. See https://go.dev/issue/57613 for more information.
+var jsFetchDisabled = !js.Global().Get("process").IsUndefined()
+
 // RoundTrip implements the RoundTripper interface using the WHATWG Fetch API.
 func (t *Transport) RoundTrip(req *Request) (*Response, error) {
 	// The Transport has a documented contract that states that if the DialContext or
@@ -52,7 +58,7 @@ func (t *Transport) RoundTrip(req *Request) (*Response, error) {
 	// though they are deprecated. Therefore, if any of these are set, we should obey
 	// the contract and dial using the regular round-trip instead. Otherwise, we'll try
 	// to fall back on the Fetch API, unless it's not available.
-	if t.Dial != nil || t.DialContext != nil || t.DialTLS != nil || t.DialTLSContext != nil || jsFetchMissing {
+	if t.Dial != nil || t.DialContext != nil || t.DialTLS != nil || t.DialTLSContext != nil || jsFetchMissing || jsFetchDisabled {
 		return t.roundTrip(req)
 	}