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LICENSEH A D14-Jan-20201.3 KiB2419

MakefileH A D14-Jan-2020871 4533

README.mdH A D14-Jan-20202.7 KiB6044

appveyor.ymlH A D14-Jan-2020639 3325

bench_test.goH A D14-Jan-20201.9 KiB11197

errors.goH A D14-Jan-20207.3 KiB289144

errors_test.goH A D14-Jan-20205.5 KiB252216

example_test.goH A D14-Jan-20205.3 KiB20676

format_test.goH A D14-Jan-202013.1 KiB561491

go113.goH A D14-Jan-20201.4 KiB399

go113_test.goH A D14-Jan-20203.1 KiB179165

json_test.goH A D14-Jan-20201,006 5248

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stack_test.goH A D14-Jan-20204.7 KiB251233

README.md

1# errors [![Travis-CI](https://travis-ci.org/pkg/errors.svg)](https://travis-ci.org/pkg/errors) [![AppVeyor](https://ci.appveyor.com/api/projects/status/b98mptawhudj53ep/branch/master?svg=true)](https://ci.appveyor.com/project/davecheney/errors/branch/master) [![GoDoc](https://godoc.org/github.com/pkg/errors?status.svg)](http://godoc.org/github.com/pkg/errors) [![Report card](https://goreportcard.com/badge/github.com/pkg/errors)](https://goreportcard.com/report/github.com/pkg/errors) [![Sourcegraph](https://sourcegraph.com/github.com/pkg/errors/-/badge.svg)](https://sourcegraph.com/github.com/pkg/errors?badge)
2
3Package errors provides simple error handling primitives.
4
5`go get github.com/pkg/errors`
6
7The traditional error handling idiom in Go is roughly akin to
8```go
9if err != nil {
10        return err
11}
12```
13which applied recursively up the call stack results in error reports without context or debugging information. The errors package allows programmers to add context to the failure path in their code in a way that does not destroy the original value of the error.
14
15## Adding context to an error
16
17The errors.Wrap function returns a new error that adds context to the original error. For example
18```go
19_, err := ioutil.ReadAll(r)
20if err != nil {
21        return errors.Wrap(err, "read failed")
22}
23```
24## Retrieving the cause of an error
25
26Using `errors.Wrap` constructs a stack of errors, adding context to the preceding error. Depending on the nature of the error it may be necessary to reverse the operation of errors.Wrap to retrieve the original error for inspection. Any error value which implements this interface can be inspected by `errors.Cause`.
27```go
28type causer interface {
29        Cause() error
30}
31```
32`errors.Cause` will recursively retrieve the topmost error which does not implement `causer`, which is assumed to be the original cause. For example:
33```go
34switch err := errors.Cause(err).(type) {
35case *MyError:
36        // handle specifically
37default:
38        // unknown error
39}
40```
41
42[Read the package documentation for more information](https://godoc.org/github.com/pkg/errors).
43
44## Roadmap
45
46With the upcoming [Go2 error proposals](https://go.googlesource.com/proposal/+/master/design/go2draft.md) this package is moving into maintenance mode. The roadmap for a 1.0 release is as follows:
47
48- 0.9. Remove pre Go 1.9 and Go 1.10 support, address outstanding pull requests (if possible)
49- 1.0. Final release.
50
51## Contributing
52
53Because of the Go2 errors changes, this package is not accepting proposals for new functionality. With that said, we welcome pull requests, bug fixes and issue reports.
54
55Before sending a PR, please discuss your change by raising an issue.
56
57## License
58
59BSD-2-Clause
60