Remove imports of golang.org/x/xerrors

This package was only intended to be used during the migration toward
better error handling/wrapping, which is now included by default in Go
1.13.

xerrors.New is now errors.New
xerrors.Errorf is not fmt.Errorf

Some packages imported a K8s errors package as "errors", and this change
now names that import "kerrors".

Some format string errors were found in migrating to fmt.Errorf, since
xerrors.Errorf formatting errors weren't considered errors when running
tests. Those have been fixed.

pkg/apis/pipeline/v1alpha1/build_gcs_resource.go

@@ -22,7 +22,6 @@ import (
 
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline"
 	"github.com/tektoncd/pipeline/pkg/names"
-	"golang.org/x/xerrors"
 	corev1 "k8s.io/api/core/v1"
 )
 
@@ -72,10 +71,10 @@ type BuildGCSResource struct {
 // NewBuildGCSResource creates a new BuildGCS resource to pass to a Task.
 func NewBuildGCSResource(images pipeline.Images, r *PipelineResource) (*BuildGCSResource, error) {
 	if r.Spec.Type != PipelineResourceTypeStorage {
-		return nil, xerrors.Errorf("BuildGCSResource: Cannot create a BuildGCS resource from a %s Pipeline Resource", r.Spec.Type)
+		return nil, fmt.Errorf("BuildGCSResource: Cannot create a BuildGCS resource from a %s Pipeline Resource", r.Spec.Type)
 	}
 	if r.Spec.SecretParams != nil {
-		return nil, xerrors.Errorf("BuildGCSResource: %s cannot support artifacts on private bucket", r.Name)
+		return nil, fmt.Errorf("BuildGCSResource: %s cannot support artifacts on private bucket", r.Name)
 	}
 	var location string
 	var aType GCSArtifactType
@@ -87,15 +86,15 @@ func NewBuildGCSResource(images pipeline.Images, r *PipelineResource) (*BuildGCS
 			var err error
 			aType, err = getArtifactType(param.Value)
 			if err != nil {
-				return nil, xerrors.Errorf("BuildGCSResource %s : %w", r.Name, err)
+				return nil, fmt.Errorf("BuildGCSResource %s : %w", r.Name, err)
 			}
 		}
 	}
 	if location == "" {
-		return nil, xerrors.Errorf("BuildGCSResource: Need Location to be specified in order to create BuildGCS resource %s", r.Name)
+		return nil, fmt.Errorf("BuildGCSResource: Need Location to be specified in order to create BuildGCS resource %s", r.Name)
 	}
 	if aType == GCSArtifactType("") {
-		return nil, xerrors.Errorf("BuildGCSResource: Need ArtifactType to be specified to create BuildGCS resource %s", r.Name)
+		return nil, fmt.Errorf("BuildGCSResource: Need ArtifactType to be specified to create BuildGCS resource %s", r.Name)
 	}
 	return &BuildGCSResource{
 		Name:                 r.Name,
@@ -162,5 +161,5 @@ func getArtifactType(val string) (GCSArtifactType, error) {
 			return a, nil
 		}
 	}
-	return "", xerrors.Errorf("Invalid ArtifactType %s. Should be one of %s", val, validArtifactTypes)
+	return "", fmt.Errorf("Invalid ArtifactType %s. Should be one of %s", val, validArtifactTypes)
 }

pkg/apis/pipeline/v1alpha1/cluster_resource.go

@@ -19,11 +19,11 @@ package v1alpha1
 import (
 	b64 "encoding/base64"
 	"encoding/json"
+	"fmt"
 	"strconv"
 	"strings"
 
 	"github.com/tektoncd/pipeline/pkg/names"
-	"golang.org/x/xerrors"
 	corev1 "k8s.io/api/core/v1"
 )
 
@@ -57,7 +57,7 @@ type ClusterResource struct {
 // NewClusterResource create a new k8s cluster resource to pass to a pipeline task
 func NewClusterResource(kubeconfigWriterImage string, r *PipelineResource) (*ClusterResource, error) {
 	if r.Spec.Type != PipelineResourceTypeCluster {
-		return nil, xerrors.Errorf("ClusterResource: Cannot create a Cluster resource from a %s Pipeline Resource", r.Spec.Type)
+		return nil, fmt.Errorf("ClusterResource: Cannot create a Cluster resource from a %s Pipeline Resource", r.Spec.Type)
 	}
 	clusterResource := ClusterResource{
 		Type:                  r.Spec.Type,

pkg/apis/pipeline/v1alpha1/gcs_resource.go

@@ -23,7 +23,6 @@ import (
 
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline"
 	"github.com/tektoncd/pipeline/pkg/names"
-	"golang.org/x/xerrors"
 	corev1 "k8s.io/api/core/v1"
 )
 
@@ -48,7 +47,7 @@ type GCSResource struct {
 // NewGCSResource creates a new GCS resource to pass to a Task
 func NewGCSResource(images pipeline.Images, r *PipelineResource) (*GCSResource, error) {
 	if r.Spec.Type != PipelineResourceTypeStorage {
-		return nil, xerrors.Errorf("GCSResource: Cannot create a GCS resource from a %s Pipeline Resource", r.Spec.Type)
+		return nil, fmt.Errorf("GCSResource: Cannot create a GCS resource from a %s Pipeline Resource", r.Spec.Type)
 	}
 	var location string
 	var locationSpecified, dir bool
@@ -66,7 +65,7 @@ func NewGCSResource(images pipeline.Images, r *PipelineResource) (*GCSResource,
 	}
 
 	if !locationSpecified {
-		return nil, xerrors.Errorf("GCSResource: Need Location to be specified in order to create GCS resource %s", r.Name)
+		return nil, fmt.Errorf("GCSResource: Need Location to be specified in order to create GCS resource %s", r.Name)
 	}
 	return &GCSResource{
 		Name:        r.Name,
@@ -132,7 +131,7 @@ func (s *GCSResource) GetOutputTaskModifier(ts *TaskSpec, path string) (TaskModi
 // GetInputTaskModifier returns the TaskModifier to be used when this resource is an input.
 func (s *GCSResource) GetInputTaskModifier(ts *TaskSpec, path string) (TaskModifier, error) {
 	if path == "" {
-		return nil, xerrors.Errorf("GCSResource: Expect Destination Directory param to be set %s", s.Name)
+		return nil, fmt.Errorf("GCSResource: Expect Destination Directory param to be set %s", s.Name)
 	}
 	var args []string
 	if s.TypeDir {

pkg/apis/pipeline/v1alpha1/git_resource.go

@@ -17,10 +17,10 @@ limitations under the License.
 package v1alpha1
 
 import (
+	"fmt"
 	"strings"
 
 	"github.com/tektoncd/pipeline/pkg/names"
-	"golang.org/x/xerrors"
 	corev1 "k8s.io/api/core/v1"
 )
 
@@ -48,7 +48,7 @@ type GitResource struct {
 // NewGitResource creates a new git resource to pass to a Task
 func NewGitResource(gitImage string, r *PipelineResource) (*GitResource, error) {
 	if r.Spec.Type != PipelineResourceTypeGit {
-		return nil, xerrors.Errorf("GitResource: Cannot create a Git resource from a %s Pipeline Resource", r.Spec.Type)
+		return nil, fmt.Errorf("GitResource: Cannot create a Git resource from a %s Pipeline Resource", r.Spec.Type)
 	}
 	gitResource := GitResource{
 		Name:       r.Name,

pkg/apis/pipeline/v1alpha1/image_resource.go

@@ -18,15 +18,14 @@ package v1alpha1
 
 import (
 	"encoding/json"
+	"fmt"
 	"strings"
-
-	"golang.org/x/xerrors"
 )
 
 // NewImageResource creates a new ImageResource from a PipelineResource.
 func NewImageResource(r *PipelineResource) (*ImageResource, error) {
 	if r.Spec.Type != PipelineResourceTypeImage {
-		return nil, xerrors.Errorf("ImageResource: Cannot create an Image resource from a %s Pipeline Resource", r.Spec.Type)
+		return nil, fmt.Errorf("ImageResource: Cannot create an Image resource from a %s Pipeline Resource", r.Spec.Type)
 	}
 	ir := &ImageResource{
 		Name: r.Name,

pkg/apis/pipeline/v1alpha1/pipeline_validation.go

@@ -25,7 +25,6 @@ import (
 	"github.com/tektoncd/pipeline/pkg/list"
 	"github.com/tektoncd/pipeline/pkg/reconciler/pipeline/dag"
 	"github.com/tektoncd/pipeline/pkg/substitution"
-	"golang.org/x/xerrors"
 	"k8s.io/apimachinery/pkg/api/equality"
 	"k8s.io/apimachinery/pkg/util/validation"
 	"knative.dev/pkg/apis"
@@ -67,7 +66,7 @@ func validateDeclaredResources(ps *PipelineSpec) error {
 	}
 	missing := list.DiffLeft(required, provided)
 	if len(missing) > 0 {
-		return xerrors.Errorf("Pipeline declared resources didn't match usage in Tasks: Didn't provide required values: %s", missing)
+		return fmt.Errorf("Pipeline declared resources didn't match usage in Tasks: Didn't provide required values: %s", missing)
 	}
 	return nil
 }
@@ -99,10 +98,10 @@ func validateFrom(tasks []PipelineTask) error {
 				for _, pb := range rd.From {
 					outputs, found := taskOutputs[pb]
 					if !found {
-						return xerrors.Errorf("expected resource %s to be from task %s, but task %s doesn't exist", rd.Resource, pb, pb)
+						return fmt.Errorf("expected resource %s to be from task %s, but task %s doesn't exist", rd.Resource, pb, pb)
 					}
 					if !isOutput(outputs, rd.Resource) {
-						return xerrors.Errorf("the resource %s from %s must be an output but is an input", rd.Resource, pb)
+						return fmt.Errorf("the resource %s from %s must be an output but is an input", rd.Resource, pb)
 					}
 				}
 			}

pkg/apis/pipeline/v1alpha1/resource_types.go

@@ -17,10 +17,11 @@ limitations under the License.
 package v1alpha1
 
 import (
+	"fmt"
+
 	"github.com/google/go-cmp/cmp"
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline"
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline/v1alpha2"
-	"golang.org/x/xerrors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
@@ -82,7 +83,7 @@ type InternalTaskModifier = v1alpha2.InternalTaskModifier
 func checkStepNotAlreadyAdded(s Step, steps []Step) error {
 	for _, step := range steps {
 		if s.Name == step.Name {
-			return xerrors.Errorf("Step %s cannot be added again", step.Name)
+			return fmt.Errorf("Step %s cannot be added again", step.Name)
 		}
 	}
 	return nil
@@ -117,7 +118,7 @@ func ApplyTaskModifier(ts *TaskSpec, tm TaskModifier) error {
 			if volume.Name == v.Name {
 				// If a Volume with the same name but different contents has already been added, we can't add both
 				if d := cmp.Diff(volume, v); d != "" {
-					return xerrors.Errorf("Tried to add volume %s already added but with different contents", volume.Name)
+					return fmt.Errorf("Tried to add volume %s already added but with different contents", volume.Name)
 				}
 				// If an identical Volume has already been added, don't add it again
 				alreadyAdded = true
@@ -225,5 +226,5 @@ func ResourceFromType(r *PipelineResource, images pipeline.Images) (PipelineReso
 	case PipelineResourceTypeCloudEvent:
 		return NewCloudEventResource(r)
 	}
-	return nil, xerrors.Errorf("%s is an invalid or unimplemented PipelineResource", r.Spec.Type)
+	return nil, fmt.Errorf("%s is an invalid or unimplemented PipelineResource", r.Spec.Type)
 }

pkg/apis/pipeline/v1alpha1/storage_resource.go

@@ -21,7 +21,6 @@ import (
 	"strings"
 
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline"
-	"golang.org/x/xerrors"
 	corev1 "k8s.io/api/core/v1"
 )
 
@@ -48,7 +47,7 @@ type PipelineStorageResourceInterface interface {
 // to add input and output steps and volumes to an executing pod.
 func NewStorageResource(images pipeline.Images, r *PipelineResource) (PipelineStorageResourceInterface, error) {
 	if r.Spec.Type != PipelineResourceTypeStorage {
-		return nil, xerrors.Errorf("StoreResource: Cannot create a storage resource from a %s Pipeline Resource", r.Spec.Type)
+		return nil, fmt.Errorf("StoreResource: Cannot create a storage resource from a %s Pipeline Resource", r.Spec.Type)
 	}
 
 	for _, param := range r.Spec.Params {
@@ -59,11 +58,11 @@ func NewStorageResource(images pipeline.Images, r *PipelineResource) (PipelineSt
 			case strings.EqualFold(param.Value, string(PipelineResourceTypeBuildGCS)):
 				return NewBuildGCSResource(images, r)
 			default:
-				return nil, xerrors.Errorf("%s is an invalid or unimplemented PipelineStorageResource", param.Value)
+				return nil, fmt.Errorf("%s is an invalid or unimplemented PipelineStorageResource", param.Value)
 			}
 		}
 	}
-	return nil, xerrors.Errorf("StoreResource: Cannot create a storage resource without type %s in spec", r.Name)
+	return nil, fmt.Errorf("StoreResource: Cannot create a storage resource without type %s in spec", r.Name)
 }
 
 func getStorageVolumeSpec(s PipelineStorageResourceInterface, spec TaskSpec) []corev1.Volume {

pkg/apis/pipeline/v1alpha2/resource_types.go

@@ -17,8 +17,9 @@ limitations under the License.
 package v1alpha2
 
 import (
+	"fmt"
+
 	"github.com/google/go-cmp/cmp"
-	"golang.org/x/xerrors"
 	v1 "k8s.io/api/core/v1"
 )
 
@@ -152,7 +153,7 @@ func ApplyTaskModifier(ts *TaskSpec, tm TaskModifier) error {
 			if volume.Name == v.Name {
 				// If a Volume with the same name but different contents has already been added, we can't add both
 				if d := cmp.Diff(volume, v); d != "" {
-					return xerrors.Errorf("Tried to add volume %s already added but with different contents", volume.Name)
+					return fmt.Errorf("Tried to add volume %s already added but with different contents", volume.Name)
 				}
 				// If an identical Volume has already been added, don't add it again
 				alreadyAdded = true
@@ -169,7 +170,7 @@ func ApplyTaskModifier(ts *TaskSpec, tm TaskModifier) error {
 func checkStepNotAlreadyAdded(s Step, steps []Step) error {
 	for _, step := range steps {
 		if s.Name == step.Name {
-			return xerrors.Errorf("Step %s cannot be added again", step.Name)
+			return fmt.Errorf("Step %s cannot be added again", step.Name)
 		}
 	}
 	return nil

pkg/artifacts/artifacts_storage.go

@@ -24,7 +24,6 @@ import (
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline/v1alpha1"
 	"github.com/tektoncd/pipeline/pkg/system"
 	"go.uber.org/zap"
-	"golang.org/x/xerrors"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/resource"
@@ -180,7 +179,7 @@ func ConfigMapNeedsPVC(configMap *corev1.ConfigMap, err error, logger *zap.Sugar
 		if errors.IsNotFound(err) {
 			return true, nil
 		}
-		return false, xerrors.Errorf("couldn't determine if PVC was needed from config map: %w", err)
+		return false, fmt.Errorf("couldn't determine if PVC was needed from config map: %w", err)
 	}
 	if configMap == nil {
 		return true, nil
@@ -206,7 +205,7 @@ func GetArtifactStorage(images pipeline.Images, prName string, c kubernetes.Inte
 	configMap, err := c.CoreV1().ConfigMaps(system.GetNamespace()).Get(BucketConfigName, metav1.GetOptions{})
 	pvc, err := ConfigMapNeedsPVC(configMap, err, logger)
 	if err != nil {
-		return nil, xerrors.Errorf("couldn't determine if PVC was needed from config map: %w", err)
+		return nil, fmt.Errorf("couldn't determine if PVC was needed from config map: %w", err)
 	}
 	if pvc {
 		return &v1alpha1.ArtifactPVC{Name: prName, ShellImage: images.ShellImage}, nil
@@ -252,7 +251,7 @@ func createPVC(pr *v1alpha1.PipelineRun, c kubernetes.Interface) (*corev1.Persis
 
 			configMap, err := c.CoreV1().ConfigMaps(system.GetNamespace()).Get(PvcConfigName, metav1.GetOptions{})
 			if err != nil && !errors.IsNotFound(err) {
-				return nil, xerrors.Errorf("failed to get PVC ConfigMap %s for %q due to error: %w", PvcConfigName, pr.Name, err)
+				return nil, fmt.Errorf("failed to get PVC ConfigMap %s for %q due to error: %w", PvcConfigName, pr.Name, err)
 			}
 			var pvcSizeStr string
 			var pvcStorageClassNameStr string
@@ -265,7 +264,7 @@ func createPVC(pr *v1alpha1.PipelineRun, c kubernetes.Interface) (*corev1.Persis
 			}
 			pvcSize, err := resource.ParseQuantity(pvcSizeStr)
 			if err != nil {
-				return nil, xerrors.Errorf("failed to create Persistent Volume spec for %q due to error: %w", pr.Name, err)
+				return nil, fmt.Errorf("failed to create Persistent Volume spec for %q due to error: %w", pr.Name, err)
 			}
 			var pvcStorageClassName *string
 			if pvcStorageClassNameStr == "" {
@@ -277,22 +276,22 @@ func createPVC(pr *v1alpha1.PipelineRun, c kubernetes.Interface) (*corev1.Persis
 			pvcSpec := GetPVCSpec(pr, pvcSize, pvcStorageClassName)
 			pvc, err := c.CoreV1().PersistentVolumeClaims(pr.Namespace).Create(pvcSpec)
 			if err != nil {
-				return nil, xerrors.Errorf("failed to claim Persistent Volume %q due to error: %w", pr.Name, err)
+				return nil, fmt.Errorf("failed to claim Persistent Volume %q due to error: %w", pr.Name, err)
 			}
 			return pvc, nil
 		}
-		return nil, xerrors.Errorf("failed to get claim Persistent Volume %q due to error: %w", pr.Name, err)
+		return nil, fmt.Errorf("failed to get claim Persistent Volume %q due to error: %w", pr.Name, err)
 	}
 	return nil, nil
 }
 
 func deletePVC(pr *v1alpha1.PipelineRun, c kubernetes.Interface) error {
 	if _, err := c.CoreV1().PersistentVolumeClaims(pr.Namespace).Get(GetPVCName(pr), metav1.GetOptions{}); err != nil {
 		if !errors.IsNotFound(err) {
-			return xerrors.Errorf("failed to get Persistent Volume %q due to error: %w", GetPVCName(pr), err)
+			return fmt.Errorf("failed to get Persistent Volume %q due to error: %w", GetPVCName(pr), err)
 		}
 	} else if err := c.CoreV1().PersistentVolumeClaims(pr.Namespace).Delete(GetPVCName(pr), &metav1.DeleteOptions{}); err != nil {
-		return xerrors.Errorf("failed to delete Persistent Volume %q due to error: %w", pr.Name, err)
+		return fmt.Errorf("failed to delete Persistent Volume %q due to error: %w", pr.Name, err)
 	}
 	return nil
 }

pkg/credentials/dockercreds/creds.go

@@ -26,7 +26,6 @@ import (
 	"path/filepath"
 	"strings"
 
-	"golang.org/x/xerrors"
 	corev1 "k8s.io/api/core/v1"
 
 	"github.com/tektoncd/pipeline/pkg/credentials"
@@ -70,13 +69,13 @@ func (dc *basicDocker) String() string {
 func (dc *basicDocker) Set(value string) error {
 	parts := strings.Split(value, "=")
 	if len(parts) != 2 {
-		return xerrors.Errorf("Expect entries of the form secret=url, got: %v", value)
+		return fmt.Errorf("Expect entries of the form secret=url, got: %v", value)
 	}
 	secret := parts[0]
 	url := parts[1]
 
 	if _, ok := dc.Entries[url]; ok {
-		return xerrors.Errorf("Multiple entries for url: %v", url)
+		return fmt.Errorf("Multiple entries for url: %v", url)
 	}
 
 	e, err := newEntry(secret)

pkg/credentials/gitcreds/basic.go

@@ -24,7 +24,6 @@ import (
 	"path/filepath"
 	"strings"
 
-	"golang.org/x/xerrors"
 	corev1 "k8s.io/api/core/v1"
 
 	"github.com/tektoncd/pipeline/pkg/credentials"
@@ -54,13 +53,13 @@ func (dc *basicGitConfig) String() string {
 func (dc *basicGitConfig) Set(value string) error {
 	parts := strings.Split(value, "=")
 	if len(parts) != 2 {
-		return xerrors.Errorf("Expect entries of the form secret=url, got: %v", value)
+		return fmt.Errorf("Expect entries of the form secret=url, got: %v", value)
 	}
 	secret := parts[0]
 	url := parts[1]
 
 	if _, ok := dc.entries[url]; ok {
-		return xerrors.Errorf("Multiple entries for url: %v", url)
+		return fmt.Errorf("Multiple entries for url: %v", url)
 	}
 
 	e, err := newBasicEntry(url, secret)