errors

package
v13.38.7 Latest Latest
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 Go to latest Published: Feb 16, 2026 License: Apache-2.0 Imports: 3 Imported by: 15

Documentation

Overview

Package errutil provides methods for working with errors

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

func As 

func As(err error, target any) bool

As finds the first error in err's tree that matches target, and if one is found, sets target to that error value and returns true. Otherwise, it returns false.

func Chain 

func Chain(funcs ...func() error) error

Chain executes functions in chain and if one of them returns an error, this function stops the chain execution and returns that error

Example 
f1 := func() error { return nil }
f2 := func() error { return nil }
f3 := func() error { return fmt.Errorf("Error 3") }
f4 := func() error { return fmt.Errorf("Error 4") }

err := Chain(f1, f2, f3, f4)

fmt.Println(err.Error())

Output:

Error 3

func Is 

func Is(err, target error) bool

Is reports whether any error in err's tree matches target

func Join 

func Join(errs ...error) error

Join returns an error that wraps the given errors

func New 

func New(text string) error

New returns an error that formats as the given text. Each call to New returns a distinct error value even if the text is identical.

func Unwrap 

func Unwrap(err error) error

Unwrap returns the result of calling the Unwrap method on err, if err's type contains an Unwrap method returning error. Otherwise, Unwrap returns nil.

Types

type Bundle 

type Bundle struct {
	// contains filtered or unexported fields
}

Bundle is a bundle of errors

Example 
f1 := func() error { return nil }
f2 := func() error { return nil }
f3 := func() error { return fmt.Errorf("Error 3") }
f4 := func() error { return fmt.Errorf("Error 4") }

// An Bundle needs no initialization
var myErrs Bundle

myErrs.Add(f1())

// Using NewBundle you can create Bundle instance with limited capacity
errs := NewBundle(10)

errs.Add(f1())
errs.Add(f2())
errs.Add(f3())
errs.Add(f4())

fmt.Printf("Last error text: %v\n", errs.Last().Error())
fmt.Printf("Number of errors: %d\n", errs.Num())
fmt.Printf("Capacity: %d\n", errs.Cap())
fmt.Printf("Has errors: %t\n", !errs.IsEmpty())

Output:

Last error text: Error 4
Number of errors: 2
Capacity: 10
Has errors: true

func NewBundle 

func NewBundle(capacity ...int) *Bundle

NewBundle creates new errors bundle

func ToBundle 

func ToBundle(errs Errors) *Bundle

ToBundle wraps slice of errors into Bundle

Example 
e := []error{
	fmt.Errorf("Error 1"),
	fmt.Errorf("Error 2"),
	fmt.Errorf("Error 3"),
}

errs := ToBundle(e)

fmt.Printf("Last error text: %v\n", errs.Last().Error())
fmt.Printf("Number of errors: %d\n", errs.Num())
fmt.Printf("Has errors: %t\n", !errs.IsEmpty())

Output:

Last error text: Error 3
Number of errors: 3
Has errors: true

func (*Bundle) Add 

func (b *Bundle) Add(errs ...any) *Bundle

Add adds new error to slice

Example 
var errs Bundle

errs.Add(fmt.Errorf("Error 1"))
errs.Add("Error 2")
errs.Add(`Error 3`)

fmt.Printf("First: %v\n", errs.First())
fmt.Printf("Last: %v\n", errs.Last())

Output:

First: Error 1
Last: Error 3

func (*Bundle) Addf added in v13.35.4 

func (b *Bundle) Addf(format string, a ...any) *Bundle

Addf creates error and appends it to the bundle

Example 
var errs Bundle

errs.Addf("Error %d", 1)
errs.Addf("Error %d", 2)
errs.Addf("Error %d", 3)

fmt.Printf("First: %v\n", errs.First())
fmt.Printf("Last: %v\n", errs.Last())

Output:

First: Error 1
Last: Error 3

func (*Bundle) All 

func (b *Bundle) All() Errors

All returns all errors in slice

Example 
var errs Bundle

errs.Add(fmt.Errorf("Error 1"))
errs.Add(fmt.Errorf("Error 2"))
errs.Add(fmt.Errorf("Error 3"))

fmt.Printf("Errors: %v\n", errs.All())

Output:

Errors: [Error 1 Error 2 Error 3]

func (*Bundle) Cap 

func (b *Bundle) Cap() int

Cap returns maximum bundle capacity

Example 
errs := NewBundle(2)

errs.Add(fmt.Errorf("Error 1"))
errs.Add(fmt.Errorf("Error 2"))
errs.Add(fmt.Errorf("Error 3"))

fmt.Printf("Errors cap: %d\n", errs.Cap())
fmt.Printf("First: %v\n", errs.First())
fmt.Printf("Last: %v\n", errs.Last())

Output:

Errors cap: 2
First: Error 2
Last: Error 3

func (*Bundle) Error 

func (b *Bundle) Error(prefix string) string

Error returns text of all errors

Example 
var errs Bundle

errs.Add(fmt.Errorf("Error 1"))
errs.Add(fmt.Errorf("Error 2"))
errs.Add(fmt.Errorf("Error 3"))

fmt.Printf("Errors:\n%s\n", errs.Error(" - "))

Output:

Errors:
 - Error 1
 - Error 2
 - Error 3

func (*Bundle) First 

func (b *Bundle) First() error

First returns the first error in bundle

Example 
var errs Bundle

errs.Add(fmt.Errorf("Error 1"))
errs.Add(fmt.Errorf("Error 2"))
errs.Add(fmt.Errorf("Error 3"))

fmt.Printf("First: %v\n", errs.First())

Output:

First: Error 1

func (*Bundle) Get 

func (b *Bundle) Get(index int) error

Get returns error by it index

Example 
var errs Bundle

errs.Add(fmt.Errorf("Error 1"))
errs.Add(fmt.Errorf("Error 2"))
errs.Add(fmt.Errorf("Error 3"))

fmt.Printf("Index 1: %v\n", errs.Get(1))
fmt.Printf("Index 99: %v\n", errs.Get(99))

Output:

Index 1: Error 2
Index 99: <nil>

func (*Bundle) IsEmpty 

func (b *Bundle) IsEmpty() bool

IsEmpty returns true if bundle is empty

Example 
var errs Bundle

fmt.Printf("Has errors: %t\n", !errs.IsEmpty())

errs.Add(fmt.Errorf("Error"))

fmt.Printf("Has errors: %t\n", !errs.IsEmpty())

Output:

Has errors: false
Has errors: true

func (*Bundle) Last 

func (b *Bundle) Last() error

Last returns the last error in bundle

Example 
var errs Bundle

errs.Add(fmt.Errorf("Error 1"))
errs.Add(fmt.Errorf("Error 2"))
errs.Add(fmt.Errorf("Error 3"))

fmt.Printf("Last: %v\n", errs.Last())

Output:

Last: Error 3

func (*Bundle) Num 

func (b *Bundle) Num() int

Num returns number of errors

Example 
var errs Bundle

errs.Add(fmt.Errorf("Error 1"))
errs.Add(fmt.Errorf("Error 2"))
errs.Add(fmt.Errorf("Error 3"))

fmt.Printf("Errors num: %d\n", errs.Num())

Output:

Errors num: 3

func (*Bundle) Reset 

func (b *Bundle) Reset()

Reset resets instance to be empty

Example 
var errs Bundle

errs.Add(fmt.Errorf("Error"))
errs.Reset()

fmt.Printf("Has errors: %t\n", !errs.IsEmpty())

Output:

Has errors: false

type Errors 

type Errors []error

Errors is a slice with errors

func (Errors) Error 

func (e Errors) Error(prefix string) string

Error returns combined text of all errors in the slice

Example 
errs := Errors{
	fmt.Errorf("Error 1"),
	fmt.Errorf("Error 2"),
	fmt.Errorf("Error 3"),
}

fmt.Printf("Errors:\n%s\n", errs.Error(" - "))

Output:

Errors:
 - Error 1
 - Error 2
 - Error 3

func (Errors) First 

func (e Errors) First() error

Last returns the first error from the slice

Example 
errs := Errors{
	fmt.Errorf("Error 1"),
	fmt.Errorf("Error 2"),
	fmt.Errorf("Error 3"),
}

fmt.Printf("First: %v\n", errs.First())

Output:

First: Error 1

func (Errors) Get 

func (e Errors) Get(index int) error

Get returns error with given index

Example 
errs := Errors{
	fmt.Errorf("Error 1"),
	fmt.Errorf("Error 2"),
	fmt.Errorf("Error 3"),
}

fmt.Printf("Index 1: %v\n", errs.Get(1))
fmt.Printf("Index 99: %v\n", errs.Get(99))

Output:

Index 1: Error 2
Index 99: <nil>

func (Errors) IsEmpty 

func (e Errors) IsEmpty() bool

IsEmpty returns true if slice is empty

Example 
var errs Errors

fmt.Printf("Has errors: %t\n", !errs.IsEmpty())

errs = Errors{fmt.Errorf("Error 1")}

fmt.Printf("Has errors: %t\n", !errs.IsEmpty())

Output:

Has errors: false
Has errors: true

func (Errors) Last 

func (e Errors) Last() error

Last returns the last error from the slice

Example 
errs := Errors{
	fmt.Errorf("Error 1"),
	fmt.Errorf("Error 2"),
	fmt.Errorf("Error 3"),
}

fmt.Printf("Last: %v\n", errs.Last())

Output:

Last: Error 3

func (Errors) Num 

func (e Errors) Num() int

Num returns size of the slice

Example 
errs := Errors{
	fmt.Errorf("Error 1"),
	fmt.Errorf("Error 2"),
	fmt.Errorf("Error 3"),
}

fmt.Printf("Errors num: %d\n", errs.Num())

Output:

Errors num: 3

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