From e7109766ab2bcd05a23c03e9060ce885df9ea5ff Mon Sep 17 00:00:00 2001
From: Elias Naur <elias.naur@gmail.com>
Date: Fri, 27 Jan 2017 18:29:22 +0100
Subject: [PATCH] cmd/gomobile: test for XCode in gomobile init

Previously, gomobile init assumed that the XCode developer tools
were available when running on darwin. That is not always the case,
in particular for Android developers on macOS.

Replace the GOOS check with an explicit check for the xcrun binary.

Change-Id: Ie5ae917288932cc641a17f904ed9822a105367cc
Reviewed-on: https://go-review.googlesource.com/35852
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
---
 cmd/gomobile/build.go   | 5 ++---
 cmd/gomobile/env.go     | 7 ++++++-
 cmd/gomobile/init.go    | 4 ++--
 cmd/gomobile/version.go | 2 +-
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/cmd/gomobile/build.go b/cmd/gomobile/build.go
index 3b36502..c1e9957 100644
--- a/cmd/gomobile/build.go
+++ b/cmd/gomobile/build.go
@@ -14,7 +14,6 @@ import (
 	"os"
 	"os/exec"
 	"regexp"
-	"runtime"
 	"strings"
 )
 
@@ -110,8 +109,8 @@ func runBuild(cmd *command) (err error) {
 		}
 	case "darwin":
 		// TODO: use targetArchs?
-		if runtime.GOOS != "darwin" {
-			return fmt.Errorf("-target=ios requires darwin host")
+		if !xcodeAvailable() {
+			return fmt.Errorf("-target=ios requires XCode")
 		}
 		if pkg.Name != "main" {
 			if err := goBuild(pkg.ImportPath, darwinArmEnv); err != nil {
diff --git a/cmd/gomobile/env.go b/cmd/gomobile/env.go
index fbddaba..e96848b 100644
--- a/cmd/gomobile/env.go
+++ b/cmd/gomobile/env.go
@@ -149,7 +149,7 @@ func envInit() (err error) {
 		}
 	}
 
-	if runtime.GOOS != "darwin" {
+	if !xcodeAvailable() {
 		return nil
 	}
 
@@ -378,3 +378,8 @@ var ndk = ndkConfig{
 		minGoVer:   go1_6,
 	},
 }
+
+func xcodeAvailable() bool {
+	_, err := exec.LookPath("xcrun")
+	return err == nil
+}
diff --git a/cmd/gomobile/init.go b/cmd/gomobile/init.go
index 5b8a5e0..120a9bb 100644
--- a/cmd/gomobile/init.go
+++ b/cmd/gomobile/init.go
@@ -315,8 +315,8 @@ var commonPkgs = []string{
 }
 
 func installDarwin() error {
-	if goos != "darwin" {
-		return nil // Only build iOS compilers on OS X.
+	if !xcodeAvailable() {
+		return nil
 	}
 	if err := installStd(darwinArmEnv); err != nil {
 		return err
diff --git a/cmd/gomobile/version.go b/cmd/gomobile/version.go
index 5ce4551..08bd317 100644
--- a/cmd/gomobile/version.go
+++ b/cmd/gomobile/version.go
@@ -51,7 +51,7 @@ func runVersion(cmd *command) (err error) {
 
 	// Supported platforms
 	platforms := "android"
-	if goos == "darwin" {
+	if xcodeAvailable() {
 		platforms = "android,ios"
 	}