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Yet another errors package, implementing error handling primitives.

License: Apache License 2.0

Go 95.00% Makefile 5.00%

golang error-handling stacktrace

go-errors's Introduction

go-errors

Yet another errors package, implementing error handling primitives with error wrapping and error tracing.

Installation

The recommended way to install go-errors is:

go get -u gopkg.in/src-d/go-errors.v1

Examples

The Kind type allows you to create new errors containing the stack trace and also check if an error is of a particular kind.

var ErrExample = errors.NewKind("example")

err := ErrExample.New()
if ErrExample.Is(err) {
	fmt.Printf("%+v\n", err)
}

// Example Output:
// example
//
// gopkg.in/src-d/errors%2v0_test.ExampleError_Format
//         /home/mcuadros/workspace/go/src/gopkg.in/src-d/errors.v0/example_test.go:60
// testing.runExample
//         /usr/lib/go/src/testing/example.go:114
// testing.RunExamples
//         /usr/lib/go/src/testing/example.go:38
// testing.(*M).Run
//         /usr/lib/go/src/testing/testing.go:744
// main.main
//         github.com/pkg/errors/_test/_testmain.go:106
// runtime.main
//         /usr/lib/go/src/runtime/proc.go:183
// runtime.goexit
//         /usr/lib/go/src/runtime/asm_amd64.s:2086

Error with format

var ErrMaxLimitReached = errors.NewKind("max. limit reached: %d")

err := ErrMaxLimitReached.New(42)
if ErrMaxLimitReached.Is(err) {
    fmt.Println(err)
}

// Output: max. limit reached: 42

Error wrapping

var ErrNetworking = errors.NewKind("network error")

err := ErrNetworking.Wrap(io.EOF)
if ErrNetworking.Is(err) {
    fmt.Println(err)
}

// Output: network error: EOF

You can find these examples and many more in the examples file.

License

Apache License 2.0, see LICENSE

go-errors's People

Contributors

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Forkers

erizocosmico abeaumont infigenie bzz forkkit jeroenherczeg isabella232

go-errors's Issues

[Proposal] Wrap errors with no kind

Sometimes as we pass the error down the line we might want to annotate the error with more information and we don't want to check its type later. For these cases, Kind is an overkill, because you need to declare a kind and then use Wrap.

A Wrap top-level function could be nice for this use-case.

if err != nil {
    return nil, errors.Wrap(err, "couldn't get value at position %d", position)
}

Instead of:

var errCantGetValueAtPos = errors.NewKind("couldn't get value at position %d")

if err != nil {
    return nil, errCantGetValueAtPos.Wrap(err, position)
}

It enables having ad-hoc error messages just for adding info and reduces the amount of kinds that need to be declared.

Reference:

xerrors.Errorf in the new experimental errors package that is probably going into Go 1.13.

[Proposal] No way to check the cause if using a mix of go-errors and standard errors

Let's imagine we are using a mix of this library and standard errors created with errors.New or fmt.Errorf.

Consider the following snippet:

var errStd = stderrors.New("something")

var errKind = errors.NewKind("something: %s")

var myErr = errKind.Wrap(errStd, "foo")

If we want to check if myErr has errStd as its cause, we need to do the following:

 err, ok := myErr.(*errors.Error)
if !ok {
  // handle
}
if err.Cause() == errStd {
}

This is potentially more cumbersome if the original error is deeply nested.
Perhaps we could have a function IsCausedBy(err, cause).

In this case, it would become:

if errors.Is(myErr, errStd) {
  // do something
}

Implementation could look like this:

func Is(err, cause error) bool {
    e, ok := err.(*Error)
    if !ok {
        return false
    }
    
    if e, ok := e.cause.(*Error); ok {
        return Is(e, cause)
    }

    return e.cause == cause
}

src-d / go-errors Goto Github PK

go-errors's Introduction

go-errors

Installation

Examples

Error with format

Error wrapping

License

go-errors's People

Contributors

Stargazers

Watchers

Forkers

go-errors's Issues

[Proposal] Wrap errors with no kind

[Proposal] No way to check the cause if using a mix of go-errors and standard errors

Add a readme

Add codecov-io

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