Merge pull request #2 from Cleverse/feature/package-errors

Package Errors

errors/README.md

@@ -1,3 +1,6 @@
+[![GoDoc](https://godoc.org/github.com/Cleverse/go-utilities/errors?status.svg)](http://godoc.org/github.com/Cleverse/go-utilities/errors)
+[![Report card](https://goreportcard.com/badge/github.com/Cleverse/go-utilities/errors)](https://goreportcard.com/report/github.com/Cleverse/go-utilities/errors)
+
 # errors
 
 Package errors adds stacktrace support to errors in go.

errors/errors_test.go

@@ -1,7 +1,6 @@
 package errors
 
 import (
-	"errors"
 	stderrors "errors"
 	"fmt"
 	"io"
@@ -20,7 +19,7 @@ func TestNew(t *testing.T) {
 		want error
 	}{
 		{"new error", New("new error")},
-		{"with format: %v", errors.New("with format: %v")},
+		{"with format: %v", stderrors.New("with format: %v")},
 	}
 
 	for _, testcase := range testcases {
@@ -48,7 +47,7 @@ func TestErrorf(t *testing.T) {
 	}, {
 		"with format: %v",
 		[]interface{}{"value"},
-		errors.New("with format: value"),
+		stderrors.New("with format: value"),
 	}}
 
 	for _, testcase := range testcases {
@@ -83,7 +82,7 @@ func TestFormatNew(t *testing.T) {
 		[]string{
 			"error\n",
 			"github.com/Cleverse/go-utilities/errors.TestFormatNew\n",
-			"errors/errors_test.go:81",
+			"errors/errors_test.go:80",
 		},
 	}, {
 		New("error"),

errors/join.go

@@ -1,3 +1,6 @@
+//go:build go1.20
+// +build go1.20
+
 package errors
 
 import (
@@ -17,3 +20,5 @@ import (
 func Join(errs ...error) error {
 	return errors.WithStack(stderrors.Join(errs...), 1)
 }
+
+// TODO: implement joinError.Format method for stack traces printing

errors/join_backward.go

@@ -0,0 +1,61 @@
+//go:build !go1.20
+// +build !go1.20
+
+package errors
+
+import errors "github.com/Cleverse/go-utilities/errors/errconstructor"
+
+// Disclaimer: functions Join is copied from the stdlib errors
+// package v1.21.3
+
+// Join returns an error that wraps the given errors with a stack trace at the point WithStack was called.
+// Any nil error values are discarded.
+// Join returns nil if every value in errs is nil.
+// The error formats as the concatenation of the strings obtained
+// by calling the Error method of each element of errs, with a newline
+// between each string.
+//
+// A non-nil error returned by Join implements the Unwrap() []error method.
+func Join(errs ...error) error {
+	n := 0
+	for _, err := range errs {
+		if err != nil {
+			n++
+		}
+	}
+	if n == 0 {
+		return nil
+	}
+	e := &joinError{
+		// stack: errors.Callers(0),
+		errs: make([]error, 0, n),
+	}
+	for _, err := range errs {
+		if err != nil {
+			e.errs = append(e.errs, err)
+		}
+	}
+	return errors.WithStack(e, 1)
+}
+
+type joinError struct {
+	// stack *errors.Stacks
+	errs []error
+}
+
+func (e *joinError) Error() string {
+	var b []byte
+	for i, err := range e.errs {
+		if i > 0 {
+			b = append(b, '\n')
+		}
+		b = append(b, err.Error()...)
+	}
+	return string(b)
+}
+
+func (e *joinError) Unwrap() []error {
+	return e.errs
+}
+
+// TODO: implement joinError.Format method for stack traces printing

errors/wrap.go

@@ -1,3 +1,6 @@
+//go:build go1.13
+// +build go1.13
+
 package errors
 
 import (