1 files changed, 17 insertions, 5 deletions
diff --git a/vendor/github.com/google/go-cmp/cmp/export_unsafe.go b/vendor/github.com/google/go-cmp/cmp/export_unsafe.go
index 59d4ee9..21eb548 100644
--- a/vendor/github.com/google/go-cmp/cmp/export_unsafe.go
+++ b/vendor/github.com/google/go-cmp/cmp/export_unsafe.go
@@ -1,6 +1,6 @@
 // Copyright 2017, The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE.md file.
+// license that can be found in the LICENSE file.
 
 // +build !purego
 
@@ -11,13 +11,25 @@ import (
 	"unsafe"
 )
 
-const supportAllowUnexported = true
+const supportExporters = true
 
 // retrieveUnexportedField uses unsafe to forcibly retrieve any field from
 // a struct such that the value has read-write permissions.
 //
 // The parent struct, v, must be addressable, while f must be a StructField
-// describing the field to retrieve.
-func retrieveUnexportedField(v reflect.Value, f reflect.StructField) reflect.Value {
-	return reflect.NewAt(f.Type, unsafe.Pointer(v.UnsafeAddr()+f.Offset)).Elem()
+// describing the field to retrieve. If addr is false,
+// then the returned value will be shallowed copied to be non-addressable.
+func retrieveUnexportedField(v reflect.Value, f reflect.StructField, addr bool) reflect.Value {
+	ve := reflect.NewAt(f.Type, unsafe.Pointer(uintptr(unsafe.Pointer(v.UnsafeAddr()))+f.Offset)).Elem()
+	if !addr {
+		// A field is addressable if and only if the struct is addressable.
+		// If the original parent value was not addressable, shallow copy the
+		// value to make it non-addressable to avoid leaking an implementation
+		// detail of how forcibly exporting a field works.
+		if ve.Kind() == reflect.Interface && ve.IsNil() {
+			return reflect.Zero(f.Type)
+		}
+		return reflect.ValueOf(ve.Interface()).Convert(f.Type)
+	}
+	return ve
 }