Make ParserArgs.ImageNamesAsSelector.Registry mandatory

it does not make sense to set a non-nil ParserArgs.ImageNamesAsSelector with no Registry in it

pkg/devfile/parser/parse.go

@@ -126,7 +126,8 @@ type ParserArgs struct {
 // all container and Kubernetes/OpenShift components matching a relative image name (say "my-image-name") of an Image component
 // will be replaced in the resulting Devfile by: "<local-registry>/<user-org>/<devfile-name>-my-image-name:some-dynamic-unique-tag".
 type ImageSelectorArgs struct {
-	// Registry is the registry base path under which images matching selectors will be built and pushed to.
+	// Registry is the registry base path under which images matching selectors will be built and pushed to. Required.
+	//
 	// Example: <local-registry>/<user-org>
 	Registry string
 	// Tag represents a tag identifier under which images matching selectors will be built and pushed to.
@@ -137,6 +138,10 @@ type ImageSelectorArgs struct {
 // ParseDevfile func populates the devfile data, parses and validates the devfile integrity.
 // Creates devfile context and runtime objects
 func ParseDevfile(args ParserArgs) (d DevfileObj, err error) {
+	if args.ImageNamesAsSelector != nil && strings.TrimSpace(args.ImageNamesAsSelector.Registry) == "" {
+		return DevfileObj{}, errors.New("registry is mandatory when setting ImageNamesAsSelector in the parser args")
+	}
+
 	if args.Data != nil {
 		d.Ctx, err = devfileCtx.NewByteContentDevfileCtx(args.Data)
 		if err != nil {

pkg/devfile/parser/parse_test.go

@@ -18,7 +18,6 @@ package parser
 import (
 	"context"
 	"fmt"
-	v1 "github.com/devfile/api/v2/pkg/apis/workspaces/v1alpha2"
 	"io/ioutil"
 	"net"
 	"net/http"
@@ -29,6 +28,8 @@ import (
 	"strings"
 	"testing"
 
+	v1 "github.com/devfile/api/v2/pkg/apis/workspaces/v1alpha2"
+
 	"github.com/devfile/api/v2/pkg/attributes"
 	devfilepkg "github.com/devfile/api/v2/pkg/devfile"
 	devfileCtx "github.com/devfile/library/v2/pkg/devfile/parser/context"
@@ -3329,6 +3330,7 @@ commands:
 	tests := []struct {
 		name             string
 		parserArgs       ParserArgs
+		wantErr          bool
 		wantBoolPropsSet []setFields
 	}{
 		{
@@ -3371,12 +3373,32 @@ commands:
 				{compProp: compBooleanProp{prop: "Secure", name: "kubernetes-deploy", value: nil, compType: v1.KubernetesComponentType}},          //unset property should be nil
 			},
 		},
+		{
+			name: "error if ImageNamesAsSelector is non-nil but ImageNamesAsSelector.Registry is empty",
+			parserArgs: ParserArgs{
+				Data:                          []byte(mainDevfile),
+				ConvertKubernetesContentInUri: &isFalse, //this is a workaround for a known parsing issue that requires support for downloading the deploy.yaml https://github.com/devfile/api/issues/1073
+				ImageNamesAsSelector:          &ImageSelectorArgs{},
+			},
+			wantErr: true,
+		},
+		{
+			name: "error if ImageNamesAsSelector is non-nil but ImageNamesAsSelector.Registry is blank",
+			parserArgs: ParserArgs{
+				Data:                          []byte(mainDevfile),
+				ConvertKubernetesContentInUri: &isFalse, //this is a workaround for a known parsing issue that requires support for downloading the deploy.yaml https://github.com/devfile/api/issues/1073
+				ImageNamesAsSelector: &ImageSelectorArgs{
+					Registry: "  \t \n",
+				},
+			},
+			wantErr: true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			d, err := ParseDevfile(tt.parserArgs)
-			if err != nil {
-				t.Errorf("Problems parsing devfile")
+			if (err != nil) != tt.wantErr {
+				t.Errorf("unexpected err when parsing devfile: error=%v, wantErr =%v", err, tt.wantErr)
 			}
 			for i, _ := range tt.wantBoolPropsSet {
 				wantProps := tt.wantBoolPropsSet[i]