first commit

internal/util/merr.go

@@ -0,0 +1,88 @@
+package util
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+// MultiError is a collection of errors that implements the error interface
+type MultiError struct {
+	errors []error
+}
+
+// NewMultiError creates a new empty MultiError
+func NewMultiError() *MultiError {
+	return &MultiError{errors: []error{}}
+}
+
+// Add appends an error to the collection if it's not nil
+func (multiErr *MultiError) Add(err error) {
+	if err != nil {
+		multiErr.errors = append(multiErr.errors, err)
+	}
+}
+
+// AddAll appends multiple errors to the collection, ignoring nil errors
+func (multiErr *MultiError) AddAll(errs ...error) {
+	for _, err := range errs {
+		multiErr.Add(err)
+	}
+}
+
+// Len returns the number of errors in the collection
+func (multiErr *MultiError) Len() int {
+	return len(multiErr.errors)
+}
+
+// Error implements the error interface
+func (multiErr *MultiError) Error() string {
+	if multiErr.Len() == 0 {
+		return ""
+	}
+
+	if multiErr.Len() == 1 {
+		return multiErr.errors[0].Error()
+	}
+
+	var sb strings.Builder
+	sb.WriteString(fmt.Sprintf("%d errors occurred:\n", multiErr.Len()))
+
+	for i, err := range multiErr.errors {
+		sb.WriteString(fmt.Sprintf("  * %s\n", err.Error()))
+		if i < multiErr.Len()-1 {
+			sb.WriteString("\n")
+		}
+	}
+
+	return sb.String()
+}
+
+// ErrorOrNil returns nil if the collection is empty, otherwise returns the flattened MultiError
+func (multiErr *MultiError) ErrorOrNil() error {
+	if multiErr.Len() == 0 {
+		return nil
+	}
+	return multiErr.Flatten()
+}
+
+// Errors returns all errors in the collection
+func (multiErr *MultiError) Errors() []error {
+	return multiErr.errors
+}
+
+// Flatten returns a new MultiError with all nested MultiErrors flattened
+func (multiErr *MultiError) Flatten() *MultiError {
+	flattened := NewMultiError()
+
+	for _, err := range multiErr.errors {
+		var merr *MultiError
+		if errors.As(err, &merr) {
+			flattened.AddAll(merr.Flatten().Errors()...)
+		} else {
+			flattened.Add(err)
+		}
+	}
+
+	return flattened
+}