golang/go · error

adb exec-out %s: %v

Error message

adb exec-out %s: %v

What it means

Returned by the go_android_exec wrapper (main.go:60) when the underlying `adb exec-out ...` command fails (cmd.Run returned non-nil). The wrapper runs tests on an Android device/emulator via adb; this error surfaces adb-level failures (device not connected, adb not installed, command rejected by device) before any exit-code parsing.

Source

Thrown at misc/go_android_exec/main.go:60

	cmd := adbCmd("exec-out", args)
	cmd.Stdout = filter
	// If the adb subprocess somehow hangs, go test will kill this wrapper
	// and wait for our os.Stderr (and os.Stdout) to close as a result.
	// However, if the os.Stderr (or os.Stdout) file descriptors are
	// passed on, the hanging adb subprocess will hold them open and
	// go test will hang forever.
	//
	// Avoid that by wrapping stderr, breaking the short circuit and
	// forcing cmd.Run to use another pipe and goroutine to pass
	// along stderr from adb.
	cmd.Stderr = struct{ io.Writer }{os.Stderr}
	err := cmd.Run()

	// Before we process err, flush any further output and get the exit code.
	exitCode, err2 := filter.Finish()

	if err != nil {
		return 0, fmt.Errorf("adb exec-out %s: %v", args, err)
	}
	return exitCode, err2
}

func adb(args ...string) error {
	if out, err := adbCmd(args...).CombinedOutput(); err != nil {
		fmt.Fprintf(os.Stderr, "adb %s\n%s", strings.Join(args, " "), out)
		return err
	}
	return nil
}

func adbCmd(args ...string) *exec.Cmd {
	if flags := os.Getenv("GOANDROID_ADB_FLAGS"); flags != "" {
		args = append(strings.Split(flags, " "), args...)
	}
	return exec.Command("adb", args...)
}

View on GitHub (pinned to b6b368adc5)

Solutions

1. Run `adb devices` and confirm your device/emulator shows as 'device' (not 'offline' or 'unauthorized').
2. Ensure adb is installed and on PATH: `which adb`.
3. Accept the RSA authorization prompt on the physical device, or restart adb: `adb kill-server && adb start-server`.
4. Re-run the test once `adb exec-out echo ok` returns 'ok'.

// Verify device connectivity before running go_android_exec.
func adbReady() error {
    out, err := exec.Command("adb", "devices").CombinedOutput()
    if err != nil {
        return fmt.Errorf("adb unavailable: %w", err)
    }
    if !strings.Contains(string(out), "\tdevice") {
        return errors.New("no authorized device connected")
    }
    return nil
}

When it happens

Trigger: Running `go test` (or go_android_exec) against an Android target with GOOS=android while adb cannot execute the command: device offline, unauthorized, adb server down, adb binary missing from PATH, or the device rejected the exec-out invocation.

Common situations: No emulator running or physical device unplugged; ADB authorization dialog not accepted on the device; mismatched adb/server versions; ANDROID_ADB_DEVICE / GOANDROID_ADDEVICE env mis-set; developer forgot to `adb start-server` or the device is in an unauthorized state.

Related errors

• no exit code (in %q)
• bad exit code: %v (in %q)
• xcrun simctl install booted %q: %v
• xcrun simctl launch booted %q: %v
• failed to locate cmd/go for target platform

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/669fc753c2790df4. Report an issue: GitHub.