Clone this repo:
  1. 839d9e9 Fix minor newline consistency issues in test files (#87) by Nick Miyake · 12 months ago master
  2. 645ef00 doc tweaks by Dave Cheney · 12 months ago v0.8.0
  3. 7433cb0 fix line numbers in fmt tests by Dave Cheney · 12 months ago
  4. 3a4fafe Fix comment on WithMessage function (#86) by Nick Miyake · 12 months ago
  5. 1398fbc tests: fixed tests on 1.4. by fabstu · 12 months ago

errors Travis-CI AppVeyor GoDoc Report card

Package errors provides simple error handling primitives.

go get github.com/pkg/errors

The traditional error handling idiom in Go is roughly akin to

if err != nil {
        return err
}

which 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.

Adding context to an error

The errors.Wrap function returns a new error that adds context to the original error. For example

_, err := ioutil.ReadAll(r)
if err != nil {
        return errors.Wrap(err, "read failed")
}

Retrieving the cause of an error

Using 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.

type causer interface {
        Cause() error
}

errors.Cause will recursively retrieve the topmost error which does not implement causer, which is assumed to be the original cause. For example:

switch err := errors.Cause(err).(type) {
case *MyError:
        // handle specifically
default:
        // unknown error
}

Read the package documentation for more information.

Contributing

We welcome pull requests, bug fixes and issue reports. With that said, the bar for adding new symbols to this package is intentionally set high.

Before proposing a change, please discuss your change by raising an issue.

Licence

BSD-2-Clause