diff options
Diffstat (limited to 'vendor/github.com/hashicorp/go-multierror/README.md')
-rw-r--r-- | vendor/github.com/hashicorp/go-multierror/README.md | 40 |
1 files changed, 37 insertions, 3 deletions
diff --git a/vendor/github.com/hashicorp/go-multierror/README.md b/vendor/github.com/hashicorp/go-multierror/README.md index ead5830f7..e92fa614c 100644 --- a/vendor/github.com/hashicorp/go-multierror/README.md +++ b/vendor/github.com/hashicorp/go-multierror/README.md @@ -14,9 +14,10 @@ be a list of errors. If the caller knows this, they can unwrap the list and access the errors. If the caller doesn't know, the error formats to a nice human-readable format. -`go-multierror` implements the -[errwrap](https://github.com/hashicorp/errwrap) interface so that it can -be used with that library, as well. +`go-multierror` is fully compatible with the Go standard library +[errors](https://golang.org/pkg/errors/) package, including the +functions `As`, `Is`, and `Unwrap`. This provides a standardized approach +for introspecting on error values. ## Installation and Docs @@ -81,6 +82,39 @@ if err := something(); err != nil { } ``` +You can also use the standard [`errors.Unwrap`](https://golang.org/pkg/errors/#Unwrap) +function. This will continue to unwrap into subsequent errors until none exist. + +**Extracting an error** + +The standard library [`errors.As`](https://golang.org/pkg/errors/#As) +function can be used directly with a multierror to extract a specific error: + +```go +// Assume err is a multierror value +err := somefunc() + +// We want to know if "err" has a "RichErrorType" in it and extract it. +var errRich RichErrorType +if errors.As(err, &errRich) { + // It has it, and now errRich is populated. +} +``` + +**Checking for an exact error value** + +Some errors are returned as exact errors such as the [`ErrNotExist`](https://golang.org/pkg/os/#pkg-variables) +error in the `os` package. You can check if this error is present by using +the standard [`errors.Is`](https://golang.org/pkg/errors/#Is) function. + +```go +// Assume err is a multierror value +err := somefunc() +if errors.Is(err, os.ErrNotExist) { + // err contains os.ErrNotExist +} +``` + **Returning a multierror only if there are errors** If you build a `multierror.Error`, you can use the `ErrorOrNil` function |