From 22b7108b87acc29de61b998b9be525536c7f30a8 Mon Sep 17 00:00:00 2001
From: Pantelis Sampaziotis <psampaz@gmail.com>
Date: Tue, 10 Sep 2019 22:17:49 +0300
Subject: [PATCH] add Unwrap to VCSError and RunError

---
 .../go/internal/modfetch/codehost/codehost.go  |  2 ++
 .../modfetch/codehost/codehost_test.go         | 18 ++++++++++++++++++
 src/cmd/go/internal/modfetch/codehost/vcs.go   |  2 ++
 .../go/internal/modfetch/codehost/vcs_test.go  | 18 ++++++++++++++++++
 4 files changed, 40 insertions(+)
 create mode 100644 src/cmd/go/internal/modfetch/codehost/codehost_test.go
 create mode 100644 src/cmd/go/internal/modfetch/codehost/vcs_test.go

diff --git a/src/cmd/go/internal/modfetch/codehost/codehost.go b/src/cmd/go/internal/modfetch/codehost/codehost.go
index a4e50d692a329c..c8f8536e32598a 100644
--- a/src/cmd/go/internal/modfetch/codehost/codehost.go
+++ b/src/cmd/go/internal/modfetch/codehost/codehost.go
@@ -242,6 +242,8 @@ func (e *RunError) Error() string {
 	return text
 }
 
+func (e *RunError) Unwrap() error { return e.Err }
+
 var dirLock sync.Map
 
 // Run runs the command line in the given directory
diff --git a/src/cmd/go/internal/modfetch/codehost/codehost_test.go b/src/cmd/go/internal/modfetch/codehost/codehost_test.go
new file mode 100644
index 00000000000000..b3a1c104ceb1f4
--- /dev/null
+++ b/src/cmd/go/internal/modfetch/codehost/codehost_test.go
@@ -0,0 +1,18 @@
+// Copyright 2019 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 file.
+
+package codehost
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestRunErrorUnwrap(t *testing.T) {
+	werr := errors.New("wrapped error")
+	err := &RunError{Err: werr}
+	if !errors.Is(err, werr) {
+		t.Error("errors.Is failed, wanted success")
+	}
+}
diff --git a/src/cmd/go/internal/modfetch/codehost/vcs.go b/src/cmd/go/internal/modfetch/codehost/vcs.go
index 48238f176c6dae..ada89979b7aca8 100644
--- a/src/cmd/go/internal/modfetch/codehost/vcs.go
+++ b/src/cmd/go/internal/modfetch/codehost/vcs.go
@@ -38,6 +38,8 @@ type VCSError struct {
 
 func (e *VCSError) Error() string { return e.Err.Error() }
 
+func (e *VCSError) Unwrap() error { return e.Err }
+
 func vcsErrorf(format string, a ...interface{}) error {
 	return &VCSError{Err: fmt.Errorf(format, a...)}
 }
diff --git a/src/cmd/go/internal/modfetch/codehost/vcs_test.go b/src/cmd/go/internal/modfetch/codehost/vcs_test.go
new file mode 100644
index 00000000000000..8205887232bc62
--- /dev/null
+++ b/src/cmd/go/internal/modfetch/codehost/vcs_test.go
@@ -0,0 +1,18 @@
+// Copyright 2019 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 file.
+
+package codehost
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestVCSErrorUnwrap(t *testing.T) {
+	werr := errors.New("wrapped error")
+	err := &VCSError{Err: werr}
+	if !errors.Is(err, werr) {
+		t.Error("errors.Is failed, wanted success")
+	}
+}