fork k8s.io/apimachinery/pkg/util/errors.Aggregate

pkg/errors/aggregate.go

@@ -16,18 +16,14 @@ limitations under the License.
 
 package errors
 
-import (
-	k8serrors "k8s.io/apimachinery/pkg/util/errors"
-)
-
-// NewAggregate is a k8s.io/apimachinery/pkg/util/errors.NewAggregate wrapper
+// NewAggregate is a k8s.io/apimachinery/pkg/util/errors.NewAggregate compatible wrapper
 // note that while it returns a StackTrace wrapped Aggregate
 // That has been Flattened and Reduced
 func NewAggregate(errlist []error) error {
 	return WithStack(
-		k8serrors.Reduce(
-			k8serrors.Flatten(
-				k8serrors.NewAggregate(errlist),
+		reduce(
+			flatten(
+				newAggregate(errlist),
 			),
 		),
 	)
@@ -35,9 +31,9 @@ func NewAggregate(errlist []error) error {
 
 // Errors returns the deepest Aggregate in a Cause chain
 func Errors(err error) []error {
-	var errors k8serrors.Aggregate
+	var errors Aggregate
 	for {
-		if v, ok := err.(k8serrors.Aggregate); ok {
+		if v, ok := err.(Aggregate); ok {
 			errors = v
 		}
 		if causerErr, ok := err.(Causer); ok {

pkg/errors/aggregate_forked.go

@@ -0,0 +1,167 @@
+/*
+Copyright 2021 The Kubernetes 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 errors
+
+import (
+	"errors"
+
+	"sigs.k8s.io/kind/pkg/internal/sets"
+)
+
+/*
+   The contents of this file are lightly forked from k8s.io/apimachinery/pkg/util/errors
+   Forking makes kind easier to import, and this code is stable.
+
+   Currently the only source changes are renaming some methods so as to not
+   export them.
+*/
+
+// Aggregate represents an object that contains multiple errors, but does not
+// necessarily have singular semantic meaning.
+// The aggregate can be used with `errors.Is()` to check for the occurrence of
+// a specific error type.
+// Errors.As() is not supported, because the caller presumably cares about a
+// specific error of potentially multiple that match the given type.
+//
+// NOTE: this type is originally from k8s.io/apimachinery/pkg/util/errors.Aggregate
+// Since it is an interface, you can use the implementing types interchangeably
+type Aggregate interface {
+	error
+	Errors() []error
+	Is(error) bool
+}
+
+func newAggregate(errlist []error) Aggregate {
+	if len(errlist) == 0 {
+		return nil
+	}
+	// In case of input error list contains nil
+	var errs []error
+	for _, e := range errlist {
+		if e != nil {
+			errs = append(errs, e)
+		}
+	}
+	if len(errs) == 0 {
+		return nil
+	}
+	return aggregate(errs)
+}
+
+// flatten takes an Aggregate, which may hold other Aggregates in arbitrary
+// nesting, and flattens them all into a single Aggregate, recursively.
+func flatten(agg Aggregate) Aggregate {
+	result := []error{}
+	if agg == nil {
+		return nil
+	}
+	for _, err := range agg.Errors() {
+		if a, ok := err.(Aggregate); ok {
+			r := flatten(a)
+			if r != nil {
+				result = append(result, r.Errors()...)
+			}
+		} else {
+			if err != nil {
+				result = append(result, err)
+			}
+		}
+	}
+	return newAggregate(result)
+}
+
+// reduce will return err or, if err is an Aggregate and only has one item,
+// the first item in the aggregate.
+func reduce(err error) error {
+	if agg, ok := err.(Aggregate); ok && err != nil {
+		switch len(agg.Errors()) {
+		case 1:
+			return agg.Errors()[0]
+		case 0:
+			return nil
+		}
+	}
+	return err
+}
+
+// This helper implements the error and Errors interfaces.  Keeping it private
+// prevents people from making an aggregate of 0 errors, which is not
+// an error, but does satisfy the error interface.
+type aggregate []error
+
+// Error is part of the error interface.
+func (agg aggregate) Error() string {
+	if len(agg) == 0 {
+		// This should never happen, really.
+		return ""
+	}
+	if len(agg) == 1 {
+		return agg[0].Error()
+	}
+	seenerrs := sets.NewString()
+	result := ""
+	agg.visit(func(err error) bool {
+		msg := err.Error()
+		if seenerrs.Has(msg) {
+			return false
+		}
+		seenerrs.Insert(msg)
+		if len(seenerrs) > 1 {
+			result += ", "
+		}
+		result += msg
+		return false
+	})
+	if len(seenerrs) == 1 {
+		return result
+	}
+	return "[" + result + "]"
+}
+
+func (agg aggregate) Is(target error) bool {
+	return agg.visit(func(err error) bool {
+		return errors.Is(err, target)
+	})
+}
+
+func (agg aggregate) visit(f func(err error) bool) bool {
+	for _, err := range agg {
+		switch err := err.(type) {
+		case aggregate:
+			if match := err.visit(f); match {
+				return match
+			}
+		case Aggregate:
+			for _, nestedErr := range err.Errors() {
+				if match := f(nestedErr); match {
+					return match
+				}
+			}
+		default:
+			if match := f(err); match {
+				return match
+			}
+		}
+	}
+
+	return false
+}
+
+// Errors is part of the Aggregate interface.
+func (agg aggregate) Errors() []error {
+	return []error(agg)
+}