gno.land/p/moul/errs/v0⧉

1// Package errs provides utilities for combining multiple errors.2// This is a simplified version of https://github.com/uber-go/multierr (MIT License),3// adapted for the Gno programming language with a focus on core functionality4// and idiomatic usage patterns.5//6// Example usage:7//8//	err1 := doSomething()9//	err2 := doSomethingElse()10//	if err := errs.Combine(err1, err2); err != nil {11//	    return err // Returns combined errors or single error12//	}13package errs1415import (16	"strings"17)1819// multiError represents multiple errors combined into one.20type multiError struct {21	errors []error22}2324// Error implements the error interface by returning a single-line representation25// of all contained errors, separated by semicolons.26func (m *multiError) Error() string {27	if m == nil || len(m.errors) == 0 {28		return ""29	}3031	var b strings.Builder32	first := true33	for _, err := range m.errors {34		if first {35			first = false36		} else {37			b.WriteString("; ")38		}39		b.WriteString(err.Error())40	}41	return b.String()42}4344// String returns a multi-line representation of the error.45func (m *multiError) String() string {46	if m == nil || len(m.errors) == 0 {47		return ""48	}4950	var b strings.Builder51	b.WriteString("the following errors occurred:")52	for _, err := range m.errors {53		b.WriteString("\n -  ")54		b.WriteString(err.Error())55	}56	return b.String()57}5859// Unwrap returns the slice of underlying errors contained in this multiError.60// Returns nil if the receiver is nil.61func (m *multiError) Unwrap() []error {62	if m == nil {63		return nil64	}65	return m.errors66}6768// Errors extracts the underlying errors from an error interface.69// If the error is a multiError, it returns its contained errors.70// If the error is nil, returns nil.71// If the error is a regular error, returns a slice containing just that error.72func Errors(err error) []error {73	if err == nil {74		return nil75	}7677	if merr, ok := err.(*multiError); ok {78		return merr.Unwrap()79	}8081	return []error{err}82}8384// Combine merges multiple errors into a single error efficiently.85// It handles several cases:86//   - If all input errors are nil, returns nil87//   - If there's exactly one non-nil error, returns that error directly88//   - If there are multiple non-nil errors, returns a multiError containing them89//   - Flattens any *multiError in the input90func Combine(errs ...error) error {91	nonNil := make([]error, 0, len(errs))92	for _, err := range errs {93		if err == nil {94			continue95		}96		if m, ok := err.(*multiError); ok && m != nil {97			nonNil = append(nonNil, m.Unwrap()...)98		} else {99			nonNil = append(nonNil, err)100		}101	}102103	switch len(nonNil) {104	case 0:105		return nil106	case 1:107		return nonNil[0]108	default:109		return &multiError{errors: nonNil}110	}111}112