diff --git a/internal/types/collapsible.go b/internal/types/collapsible.go new file mode 100644 index 0000000..a37e772 --- /dev/null +++ b/internal/types/collapsible.go @@ -0,0 +1,57 @@ +/* + Copyright The containerd Authors. + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +*/ + +package types + +import "fmt" + +// CollapsibleError indicates the error should be collapsed +type CollapsibleError interface { + CollapseError() +} + +// CollapsedError returns a new error with the collapsed +// error returned on unwrapped or when formatted with "%+v" +func CollapsedError(err error, collapsed ...error) error { + return collapsedError{err, collapsed} +} + +type collapsedError struct { + error + collapsed []error +} + +func (c collapsedError) Unwrap() []error { + return append([]error{c.error}, c.collapsed...) +} + +func (c collapsedError) Format(s fmt.State, verb rune) { + switch verb { + case 'v': + if s.Flag('+') { + fmt.Fprintf(s, "%+v", c.error) + for _, err := range c.collapsed { + fmt.Fprintf(s, "\n%+v", err) + } + return + } + fallthrough + case 's': + fmt.Fprint(s, c.Error()) + case 'q': + fmt.Fprintf(s, "%q", c.Error()) + } +}