runtime: panic: runtime error: index out of range on all commands on Darwin

[patricklunney]

Please answer these questions before submitting your issue. Thanks!

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

$ go version
panic: runtime error: index out of range

goroutine 1 [running]:
os.executable(...)
/usr/local/Cellar/go/1.10/libexec/src/os/executable_darwin.go:13
os.Executable(...)
/usr/local/Cellar/go/1.10/libexec/src/os/executable.go:21
cmd/go/internal/cfg.findGOROOT(0xc42001e2c0, 0x17)
/usr/local/Cellar/go/1.10/libexec/src/cmd/go/internal/cfg/cfg.go:107 +0x441

Does this issue reproduce with the latest release?

I don't know what version, I think 1.10 based on the .pkg download

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

OSX 10.12

$ go env
panic: runtime error: index out of range

goroutine 1 [running]:
os.executable(...)
/usr/local/Cellar/go/1.10/libexec/src/os/executable_darwin.go:13
os.Executable(...)
/usr/local/Cellar/go/1.10/libexec/src/os/executable.go:21
cmd/go/internal/cfg.findGOROOT(0xc42001e2c0, 0x17)
/usr/local/Cellar/go/1.10/libexec/src/cmd/go/internal/cfg/cfg.go:107 +0x441

What did you do?

Installed go.

Let me know if you need any other docs.
Any idea why it isn't working?

[josharian]

For some reason, runtime/os_darwin.go:sysargs failed to set os.executablePath, or set it to the empty string. There's an obvious recovery fix we should add--sanity check that os.executablePath is non-empty at the beginning of os.executable--but it would be good to know why it is empty in the first place.

Can you try modifying /usr/local/Cellar/go/1.10/libexec/src/runtime/os_darwin.go, func sysargs (at the bottom), to look like this:

func sysargs(argc int32, argv **byte) {
        println("argc", argc)
	// skip over argv, envv and the first string will be the path
	n := argc + 1
	for argv_index(argv, n) != nil {
		n++
	}
        println("n", n)
	executablePath = gostringnocopy(argv_index(argv, n+1))
        println("raw", executablePath)

	// strip "executable_path=" prefix if available, it's added after OS X 10.11.
	const prefix = "executable_path="
	if len(executablePath) > len(prefix) && executablePath[:len(prefix)] == prefix {
		executablePath = executablePath[len(prefix):]
	}
        println("final", executablePath)
}

Then run /usr/local/Cellar/go/1.10/libexec/src/make.bash, and then try go env again and let us know what it says. Thanks.

[patricklunney]

Made the change and now I get this:

$ sudo /usr/local/Cellar/go/1.10/libexec/src/make.bash
Password:
make.bash must be run from $GOROOT/src

(tried as both sudo and not sudo)

I don't have anything set to $GOROOT
$ echo $GOROOT

What should I set it as?

[uoryon]

@patricklunney You can try this.

cd /usr/local/Cellar/go/1.10/libexec/src && ./make.bash

[patricklunney]

Still didn't work:

$ cd /usr/local/Cellar/go/1.10/libexec/src && ./make.bash
panic: runtime error: index out of range

goroutine 1 [running]:
os.executable(...)
	/usr/local/Cellar/go/1.10/libexec/src/os/executable_darwin.go:13
os.Executable(...)
	/usr/local/Cellar/go/1.10/libexec/src/os/executable.go:21
cmd/go/internal/cfg.findGOROOT(0xc420024280, 0x17)
	/usr/local/Cellar/go/1.10/libexec/src/cmd/go/internal/cfg/cfg.go:107 +0x441

[josharian]

Drat. Bootstrapping. Sadly, it's going to be a bit more complicated than I thought to get a local build going for you to investigate. Are you game for it? Happy to help you through through the process.

[patricklunney]

Sure. What do I do?

[josharian]

Step one is getting you a functioning Go installation. :) Maybe grab 1.9.4 from https://golang.org/dl/ and put it in some other (non-homebrew) location and see whether it works for you. If not 1.9.4, try 1.8.x. Once that is up and running, export GOROOT_BOOTSTRAP=path/to/working/go. Try executing $GOROOT_BOOTSTRAP/bin/go version to make the envvar is set up correctly. (See https://golang.org/doc/install/source#go14 for lots more detail here.) Then try make.bash again, with that envvar.

[odeke-em]

How's it going @patricklunney? Josh posted some tips in order to bootstrap your Go installation, please take a look. Thank you.