😋 error select and combine

.gitignore

@@ -15,3 +15,4 @@ goent.sum
 
 testdata/
 !internal/checker/testdata
+pkg/filter/build/

tool/error.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"runtime"
 
+	"github.com/hashicorp/go-multierror"
 	"github.com/juju/errors"
 )
 
@@ -19,3 +20,16 @@ func TraceError(err error, skip int) error {
 	}
 	return fmt.Errorf("%s:%d: %s", file, line, err)
 }
+
+func CombineError(errs ...error) error {
+	return multierror.Append(&multierror.Error{}, errs...).ErrorOrNil()
+}
+
+func SelectError(errs ...error) error {
+	for _, err := range errs {
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

tool/error_test.go

+package tool
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCombineError(t *testing.T) {
+	err := CombineError(nil, nil)
+	assert.Nil(t, err)
+
+	err = CombineError(fmt.Errorf("err info"), nil)
+	assert.NotNil(t, err)
+
+	err = CombineError(nil, fmt.Errorf("err info"), nil)
+	assert.NotNil(t, err)
+	t.Log(err)
+}
+
+func TestSelectError(t *testing.T) {
+	err1 := fmt.Errorf("err info1")
+	err2 := fmt.Errorf("err info2")
+	err := SelectError(nil, nil)
+	assert.Nil(t, err)
+
+	err = SelectError(err1, nil, err2)
+	assert.Equal(t, err, err1)
+
+	err = SelectError(nil, err2, nil, err1)
+	assert.Equal(t, err, err2)
+}