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d7f3e542cf
Splits the signature of errors.As into two more specialized functions which catch more errors at compile-time using generics.
114 lines
2.8 KiB
Go
114 lines
2.8 KiB
Go
package errors
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import (
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"fmt"
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"github.com/cockroachdb/errors" //nolint:depguard // needed for implementation of multiError.As
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)
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// MultiError is a container for groups of errors.
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type MultiError interface {
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error
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// Errors returns all errors carried by this MultiError, or an empty slice otherwise.
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Errors() []error
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}
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// multiError is our default underlying implementation for MultiError. It is compatible
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// with cockroachdb.Error's formatting, printing, etc. and supports introspecting via
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// As, Is, and friends.
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//
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// Implementation is based on https://github.com/knz/shakespeare/blob/master/pkg/cmd/errors.go
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type multiError struct {
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errs []error
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}
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var _ MultiError = (*multiError)(nil)
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var _ Typed = (*multiError)(nil)
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func combineNonNilErrors(err1 error, err2 error) MultiError {
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multi1, ok1 := err1.(MultiError)
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multi2, ok2 := err2.(MultiError)
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// flatten
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var errs []error
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if ok1 && ok2 {
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errs = append(multi1.Errors(), multi2.Errors()...)
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} else if ok1 {
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errs = append(multi1.Errors(), err2)
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} else if ok2 {
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errs = append([]error{err1}, multi2.Errors()...)
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} else {
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errs = []error{err1, err2}
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}
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return &multiError{errs: errs}
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}
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// CombineErrors returns a MultiError from err1 and err2. If both are nil, nil is returned.
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func CombineErrors(err1, err2 error) MultiError {
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if err1 == nil && err2 == nil {
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return nil
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}
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if err1 == nil {
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if multi, ok := err2.(MultiError); ok {
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return multi
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}
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return &multiError{errs: []error{err2}}
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} else if err2 == nil {
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if multi, ok := err1.(MultiError); ok {
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return multi
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}
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return &multiError{errs: []error{err1}}
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}
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return combineNonNilErrors(err1, err2)
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}
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// Append returns a MultiError created from all given errors, skipping errs that are nil.
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// If no non-nil errors are provided, nil is returned.
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func Append(err error, errs ...error) MultiError {
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multi := CombineErrors(err, nil)
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for _, e := range errs {
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if e != nil {
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multi = CombineErrors(multi, e)
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}
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}
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return multi
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}
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func (e *multiError) Error() string { return fmt.Sprintf("%v", e) }
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func (e *multiError) Errors() []error {
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if e == nil || e.errs == nil {
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return nil
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}
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return e.errs
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}
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func (e *multiError) Cause() error { return e.errs[len(e.errs)-1] }
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func (e *multiError) Unwrap() error { return e.errs[len(e.errs)-1] }
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func (e *multiError) Is(refError error) bool {
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if e == refError {
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return true
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}
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for _, err := range e.errs {
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if Is(err, refError) {
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return true
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}
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}
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return false
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}
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func (e *multiError) As(target any) bool {
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if m, ok := target.(*multiError); ok {
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*m = *e
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return true
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}
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for _, err := range e.errs {
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// To conform to the Typed interface, 'target' has to be of type
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// any. This means we cannot use our custom As wrapper which has
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// a generic argument, so use cockroachdb's As instead.
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if errors.As(err, target) {
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return true
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}
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}
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return false
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}
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