go.errors 1.23.1.2

go.errors

C# package converted from the Go standard library by go2cs. Go version: 1.23.1

Package errors implements functions to manipulate errors.

The [New] function creates errors whose only content is a text message.

An error e wraps another error if e's type has one of the methods

Unwrap() error
Unwrap() []error

If e.Unwrap() returns a non-nil error w or a slice containing w, then we say that e wraps w. A nil error returned from e.Unwrap() indicates that e does not wrap any error. It is invalid for an Unwrap method to return an []error containing a nil error value.

An easy way to create wrapped errors is to call fmt.Errorf and apply the %w verb to the error argument:

wrapsErr := fmt.Errorf("... %w ...", ..., err, ...)

Successive unwrapping of an error creates a tree. The [Is] and [As] functions inspect an error's tree by examining first the error itself followed by the tree of each of its children in turn (pre-order, depth-first traversal).

[Is] examines the tree of its first argument looking for an error that matches the second. It reports whether it finds a match. It should be used in preference to simple equality checks:

if errors.Is(err, fs.ErrExist)

is preferable to

if err == fs.ErrExist

because the former will succeed if err wraps io/fs.ErrExist.

[As] examines the tree of its first argument looking for an error that can be assigned to its second argument, which must be a pointer. If it succeeds, it performs the assignment and returns true. Otherwise, it returns false. The form

var perr *fs.PathError
if errors.As(err, &perr) {
	fmt.Println(perr.Path)
}

is preferable to

if perr, ok := err.(*fs.PathError); ok {
	fmt.Println(perr.Path)
}

because the former will succeed if err wraps an *io/fs.PathError.

Part of the go2cs converted Go standard library. See the repository for usage and details.

Copyright 2009 The Go Authors. All rights reserved. This C# package is converted from Go standard library source; use of that source is governed by a BSD-style license that can be found in the LICENSE file. The go2cs conversion itself is distributed under the MIT license.