From 312584e609dda360336d8ac2ac1f25d05ccb4ba4 Mon Sep 17 00:00:00 2001
From: Ivan Kruglov <ivan.kruglov@booking.com>
Date: Thu, 24 Mar 2016 21:41:14 +0100
Subject: [PATCH] fix go1.6 compatibility problem in tests

https://tip.golang.org/doc/go1.6

The reflect package has resolved a long-standing incompatibility between
the gc and gccgo toolchains regarding embedded unexported struct types
containing exported fields. Code that walks data structures using
reflection, especially to implement serialization in the spirit of the
encoding/json and encoding/xml packages, may need to be updated.

The problem arises when using reflection to walk through an embedded
unexported struct-typed field into an exported field of that struct. In
this case, reflect had incorrectly reported the embedded field as exported,
by returning an empty Field.PkgPath. Now it correctly reports the field as
unexported but ignores that fact when evaluating access to exported fields
contained within the struct.

Updating: Typically, code that previously walked over structs and used

f.PkgPath != ""
to exclude inaccessible fields should now use

f.PkgPath != "" && !f.Anonymous
For example, see the changes to the implementations of encoding/json and
encoding/xml.

Also see code for more details
---
 tests/types/ff/everything.go | 61 +++++++++++++++++++++++++++++++++++-
 tests/types/types_test.go    |  7 +++--
 2 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/tests/types/ff/everything.go b/tests/types/ff/everything.go
index 11c5f21..230e151 100644
--- a/tests/types/ff/everything.go
+++ b/tests/types/ff/everything.go
@@ -17,6 +17,65 @@
 
 package ff
 
+import (
+	"regexp"
+	"runtime"
+	"strconv"
+)
+
+var ExpectedSomethingValue int8
+var GoLangVersionPre16 bool
+
+func init() {
+	// since go1.6 reflect package changed behaivour:
+	//
+	// --------
+	// https://tip.golang.org/doc/go1.6
+	//
+	// The reflect package has resolved a long-standing incompatibility between
+	// the gc and gccgo toolchains regarding embedded unexported struct types
+	// containing exported fields. Code that walks data structures using
+	// reflection, especially to implement serialization in the spirit of the
+	// encoding/json and encoding/xml packages, may need to be updated.
+	//
+	// The problem arises when using reflection to walk through an embedded
+	// unexported struct-typed field into an exported field of that struct. In
+	// this case, reflect had incorrectly reported the embedded field as exported,
+	// by returning an empty Field.PkgPath. Now it correctly reports the field as
+	// unexported but ignores that fact when evaluating access to exported fields
+	// contained within the struct.
+	//
+	// Updating: Typically, code that previously walked over structs and used
+	//
+	// f.PkgPath != ""
+	// to exclude inaccessible fields should now use
+	//
+	// f.PkgPath != "" && !f.Anonymous
+	// For example, see the changes to the implementations of encoding/json and
+	// encoding/xml.
+	//
+	// --------
+	//
+	// I didn't find better option to get Go's version rather then parsing
+	// runtime.Version(). Godoc say that Version() can return multiple things:
+	//
+	// Version returns the Go tree's version string. It is either the commit
+	// hash and date at the time of the build or, when possible, a release tag
+	// like "go1.3".
+	//
+	// So, I'll assumes that if Version() returns not a release tag, running
+	// version is younger then 1.5. Patches welcome :-)
+
+	versionRegexp := regexp.MustCompile("^go[0-9]+\\.([0-9]+)")
+	if res := versionRegexp.FindStringSubmatch(runtime.Version()); len(res) > 1 {
+		if i, _ := strconv.Atoi(res[1]); i < 6 {
+			// pre go1.6
+			GoLangVersionPre16 = true
+			ExpectedSomethingValue = 99
+		}
+	}
+}
+
 type SweetInterface interface {
 	Cats() int
 }
@@ -93,7 +152,7 @@ func NewEverything(e *Everything) {
 	}
 	e.String = "snowman->☃"
 	e.FooStruct = &Foo{Bar: 1}
-	e.Something = 99
+	e.Something = ExpectedSomethingValue
 	e.MySweetInterface = &Cats{}
 	e.MapMap = map[string]map[string]string{
 		"a": map[string]string{"b": "2", "c": "3", "d": "4"},
diff --git a/tests/types/types_test.go b/tests/types/types_test.go
index b42c4ad..2d73c06 100644
--- a/tests/types/types_test.go
+++ b/tests/types/types_test.go
@@ -57,7 +57,7 @@ func TestRoundTrip(t *testing.T) {
 		t.Fatal("Embeded struct didn't Unmarshal")
 	}
 
-	if recordTripped.Something != 99 {
+	if recordTripped.Something != ff.ExpectedSomethingValue {
 		t.Fatal("Embeded nonexported-struct didn't Unmarshal")
 	}
 }
@@ -119,8 +119,9 @@ func TestUnmarshalFull(t *testing.T) {
 		t.Fatalf("record.String decoding problem, expected: %v got: %v", expect, record.String)
 	}
 
-	if record.Something != 99 {
-		t.Fatalf("record.Something decoding problem, expected: 99 got: %v", record.Something)
+	if record.Something != ff.ExpectedSomethingValue {
+		t.Fatalf("record.Something decoding problem, expected: %d got: %v",
+			ff.ExpectedSomethingValue, record.Something)
 	}
 }