Add derrors for deferred error joins

Author: a-menshchikov

derrors/derrors.go

@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: BSD-3-Clause
+
+package derrors
+
+import (
+	"errors"
+)
+
+func Join(err *error, errs ...error) {
+	*err = errors.Join(append([]error{*err}, errs...)...)
+}

derrors/derrors_test.go

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: BSD-3-Clause
+
+package derrors_test
+
+import (
+	"errors"
+	"testing"
+
+	. "github.com/nbgrp/pkg/derrors"
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	externalErr = errors.New("external")
+	internalErr = errors.New("internal")
+)
+
+func errorFunc() error {
+	return externalErr
+}
+
+func noErrorFunc() error {
+	return nil
+}
+
+func TestJoin(t *testing.T) {
+	t.Run("internal error", func(t *testing.T) {
+		fn := func() (err error) {
+			defer Join(&err, noErrorFunc())
+			return internalErr
+		}
+
+		err := fn()
+
+		require.NotErrorIs(t, err, externalErr)
+		require.ErrorIs(t, err, internalErr)
+	})
+
+	t.Run("external error", func(t *testing.T) {
+		fn := func() (err error) {
+			defer Join(&err, errorFunc())
+			return nil
+		}
+
+		err := fn()
+
+		require.ErrorIs(t, err, externalErr)
+		require.NotErrorIs(t, err, internalErr)
+	})
+
+	t.Run("joint error", func(t *testing.T) {
+		fn := func() (err error) {
+			defer Join(&err, errorFunc())
+			return internalErr
+		}
+
+		err := fn()
+
+		require.ErrorIs(t, err, externalErr)
+		require.ErrorIs(t, err, internalErr)
+	})
+
+	t.Run("no errors", func(t *testing.T) {
+		fn := func() (err error) {
+			defer Join(&err, noErrorFunc())
+			return err
+		}
+
+		err := fn()
+
+		require.NoError(t, err)
+	})
+}

derrors/go.mod

@@ -0,0 +1,11 @@
+module github.com/nbgrp/pkg/derrors
+
+go 1.20
+
+require github.com/stretchr/testify v1.11.1
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

derrors/go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

go.work

@@ -3,6 +3,7 @@ go 1.22.0
 use (
 	./closer
 	./ctxkey
+	./derrors
 	./protowrap
 	./strcase
 	./sync