fmt.Println() panics

[Michael-F-Ellis]

Just installed gopherjs and go1.17.2 on my mac. Calls to fmt.Println() are panicking in the browser. I've reduced it to the simplest possible test case:

package main

import "fmt"

func main() {
	fmt.Println("Hello, GopherJs")
}

No errors or warning when transpiling. The error reported in the browser (via devtools) is:

Uncaught Error: runtime error: native function not implemented: internal/abi.FuncPCABI0
    at $callDeferred (..js:1506)
    at $panic (..js:1549)
    at throw$1 (runtime.go:384)
    at Object.FuncPCABI0 (wrap.go:103)
    at write (zsyscall_darwin_amd64.go:1635)
    at Write (syscall_unix.go:214)
    at ignoringEINTRIO (fd_unix.go:582)
    at Object.$packages.internal/poll.FD.ptr.Write (fd_unix.go:275)
    at Object.$packages.os.File.ptr.write (file_posix.go:49)
    at Object.$packages.os.File.ptr.Write (file.go:176)
    at Fprintln (print.go:265)
    at Object.Println (..js:23892)
    at main (main.go:6)
    at $init (..js:25201)
    at $goroutine (..js:1569)
    at $runScheduled (..js:1609)
    at $schedule (..js:1625)
    at $go (..js:1601)
    at ..js:25213
    at ..js:25216

Paths and system info:

% uname -a
Darwin michaels-mbp.lan 19.6.0 Darwin Kernel Version 19.6.0: Thu Sep 16 20:58:47 PDT 2021; root:xnu-6153.141.40.1~1/RELEASE_X86_64 x86_64

% which go
/usr/local/go/bin/go

% go version
go version go1.17.2 darwin/amd64

% gopherjs version
GopherJS 1.17.0+go1.17.1

I'm new to gopherjs (but not to Go) so this is probably some silly configuration issue but darned if I can figure it out. Any help appreciated!

[Michael-F-Ellis]

FWIW, I found the following on FuncPCABI0 at https://cs.opensource.google/go/go/+/master:src/internal/abi/abi.go;l=99

// FuncPC* intrinsics.
//
// CAREFUL: In programs with plugins, FuncPC* can return different values
// for the same function (because there are actually multiple copies of
// the same function in the address space). To be safe, don't use the
// results of this function in any == expression. It is only safe to
// use the result as an address at which to start executing code.

// FuncPCABI0 returns the entry PC of the function f, which must be a
// direct reference of a function defined as ABI0. Otherwise it is a
// compile-time error.
//
// Implemented as a compile intrinsic.
func FuncPCABI0(f interface{}) uintptr

[nevkontakte]

Hi @Michael-F-Ellis, thanks for a well-written report! This is probably a regression that happened when we upgraded to Go 1.17... Neither of the current maintainers use Macs, so this happens with disappointing regularity 😟 Since you are targeting browser, you can avoid this problem by building with GOOS=linux, I think this should fix the problem in the short term.

In the longer term I started work on https://github.com/gopherjs/gopherjs/issues/693#issuecomment-932964199, so in some near future GopherJS will stop using darwin sources entirely.

@flimzy what are your thoughts on our GOOS=darwin support? This is probably fifth or so report within the last half a year. The only case where darwin support matters is when someone is using GopherJS with NodeJS on a mac. Anecdotally everyone who reported an issue of this type was targeting browser and was ok with GOOS=linux workaround. Until #693 is done, we could probably just default to GOOS=linux and print some kind of error if we detect that we are running on Node on MacOS.

[Michael-F-Ellis]

Thanks for the quick response! GOOS=linux works for both the simple case and the real app I'm converting from wasm.

[flimzy]

@nevkontakte I think defaulting to GOOS=linux makes sense, as it's a clear improvement over the current state.

If we determine that's not sufficient for some people, we can consider adding proper darwin support in the future?