From 633184e99826a9515e7bd36fa5a89cdaf4f8bd3d Mon Sep 17 00:00:00 2001
From: Dong-hee Na <donghee.na92@gmail.com>
Date: Sat, 6 May 2017 16:00:07 +0000
Subject: [PATCH] bind: make sure GODEBUG=cgocheck=0 for Go>=1.6

---
 bind/gengo.go      | 43 ++++++++++++++++++++++++++++++++++++++++++-
 bind/utils.go      | 14 ++++++++++++++
 bind/utils_test.go | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 96 insertions(+), 1 deletion(-)
 create mode 100644 bind/utils_test.go

diff --git a/bind/gengo.go b/bind/gengo.go
index 0d9486f..58fc740 100644
--- a/bind/gengo.go
+++ b/bind/gengo.go
@@ -8,10 +8,40 @@ import (
 	"fmt"
 	"go/token"
 	"go/types"
+	"runtime"
 	"strings"
 )
 
 const (
+	checkGoVersionImport = `"strconv"
+	"strings"
+	"os"
+`
+	checkGoVersion= "_cgopy_CheckGoVersion()"
+	checkGoVersionDef = `
+func _cgopy_CheckGoVersion() {
+        godebug := os.Getenv("GODEBUG")
+        cgocheck := -1
+        var err error
+        if godebug != "" {
+		const prefix = "cgocheck="
+                for _, option := range strings.Split(godebug, ",") {
+                        if !strings.HasPrefix(option, prefix) {
+				continue
+                        }
+			cgocheck, err = strconv.Atoi(option[len(prefix):])
+                        if err != nil {
+				cgocheck = -1
+                                fmt.Fprintf(os.Stderr, "gopy: invalid cgocheck value %q (expected an integer)\n", option)
+                        }
+                }
+        }
+
+        if cgocheck != 0 {
+                fmt.Fprintf(os.Stderr, "gopy: GODEBUG=cgocheck=0 should be set for Go>=1.6\n")
+        }
+}
+`
 	goPreamble = `// Package main is an autogenerated binder stub for package %[1]s.
 // gopy gen -lang=go %[1]s
 //
@@ -30,6 +60,8 @@ import (
 	"unsafe"
 
 	%[3]s
+
+	%[4]s
 )
 
 var _ = unsafe.Pointer(nil)
@@ -111,7 +143,10 @@ func cgopy_decref(ptr unsafe.Pointer) {
 	refs.Unlock()
 }
 
+%[5]s
+
 func init() {
+	%[6]s
 	refs.Lock()
 	refs.next = -24 // Go objects get negative reference numbers. Arbitrary starting point.
 	refs.refs = make(map[unsafe.Pointer]int32)
@@ -969,7 +1004,13 @@ func (g *goGen) genPreamble() {
 		panic(err)
 	}
 
-	g.Printf(goPreamble, n, pkgcfg, pkgimport)
+	version := runtime.Version()
+	major, minor, _ := getGoVersion(version)
+	if major >= 1 && minor >= 6 {
+		g.Printf(goPreamble, n, pkgcfg, pkgimport, checkGoVersionImport, checkGoVersionDef, checkGoVersion)
+	} else {
+		g.Printf(goPreamble, n, pkgcfg, pkgimport, "", "", "")
+	}
 }
 
 func (g *goGen) tupleString(tuple []*Var) string {
diff --git a/bind/utils.go b/bind/utils.go
index be95231..de82064 100644
--- a/bind/utils.go
+++ b/bind/utils.go
@@ -13,6 +13,8 @@ import (
 	"os/exec"
 	"regexp"
 	"sort"
+	"strconv"
+	"strings"
 )
 
 func isErrorType(typ types.Type) bool {
@@ -148,3 +150,15 @@ func getPkgConfig(vers int) (string, error) {
 
 	return pkgcfg, nil
 }
+
+func getGoVersion(version string) (int64, int64, error) {
+	version_regex := regexp.MustCompile(`^go((\d+)(\.(\d+))*)`)
+	match := version_regex.FindStringSubmatch(version)
+	if match == nil {
+		return -1, -1, fmt.Errorf("gopy: invalid Go version information: %q", version)
+	}
+	version_info := strings.Split(match[1], ".")
+	major, _ := strconv.ParseInt(version_info[0], 10, 0)
+	minor, _ := strconv.ParseInt(version_info[1], 10, 0)
+	return major, minor, nil
+ }
diff --git a/bind/utils_test.go b/bind/utils_test.go
new file mode 100644
index 0000000..151b474
--- /dev/null
+++ b/bind/utils_test.go
@@ -0,0 +1,40 @@
+// Copyright 2017 The go-python Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bind
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestGetGoVersion(t *testing.T) {
+	for _, tt := range []struct {
+		info  string
+		major int64
+		minor int64
+		err   error
+	}{
+		{"go1.5", 1, 5, nil},
+		{"go1.6", 1, 6, nil},
+		{"go1.7", 1, 7, nil},
+		{"go1.8", 1, 8, nil},
+		{"gcc4", -1, -1, errors.New("gopy: invalid Go version information: \"gcc4\"")},
+		{"1.8go", -1, -1, errors.New("gopy: invalid Go version information: \"1.8go\"")},
+		{"llvm", -1, -1, errors.New("gopy: invalid Go version information: \"llvm\"")},
+	} {
+		major, minor, err := getGoVersion(tt.info)
+		if major != tt.major {
+			t.Errorf("getGoVersion(%s): expected major %d, actual %d", tt.info, tt.major, major)
+		}
+
+		if minor != tt.minor {
+			t.Errorf("getGoVersion(%s): expected major %d, actual %d", tt.info, tt.minor, minor)
+		}
+
+		if err != nil && err.Error() != tt.err.Error() {
+			t.Errorf("getGoVersion(%s): expected err %s, actual %s", tt.info, tt.err, err)
+		}
+	}
+}