Also consider wrapped errors when checking for file IsNotExist errors

Fixes #10534

common/herrors/errors_test.go

@@ -0,0 +1,36 @@
+// Copyright 2022 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package herrors
+
+import (
+	"fmt"
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+	"github.com/spf13/afero"
+)
+
+func TestIsNotExist(t *testing.T) {
+	c := qt.New(t)
+
+	c.Assert(IsNotExist(afero.ErrFileNotFound), qt.Equals, true)
+	c.Assert(IsNotExist(afero.ErrFileExists), qt.Equals, false)
+	c.Assert(IsNotExist(afero.ErrDestinationExists), qt.Equals, false)
+	c.Assert(IsNotExist(nil), qt.Equals, false)
+
+	c.Assert(IsNotExist(fmt.Errorf("foo")), qt.Equals, false)
+
+	// os.IsNotExist returns false for wrapped errors.
+	c.Assert(IsNotExist(fmt.Errorf("foo: %w", afero.ErrFileNotFound)), qt.Equals, true)
+}