Add strict platform variant check

extractor/image/image.go

@@ -26,6 +26,7 @@ type ImageCloser interface {
 	LayerInfos() (layerInfos []imageTypes.BlobInfo)
 	ConfigInfo() imageTypes.BlobInfo
 	ConfigBlob(context.Context) ([]byte, error)
+	Inspect(context.Context) (*imageTypes.ImageInspectInfo, error)
 	Close() error
 }
 
@@ -93,6 +94,22 @@ func NewImage(ctx context.Context, image Reference, transports []string, option
 		return RealImage{}, xerrors.Errorf("failed to initialize source: %w", err)
 	}
 
+	// Validate platform if variant was requested
+	if variantChoice != "" {
+		inspectInfo, err := src.Inspect(ctx)
+		if err != nil {
+			return RealImage{}, xerrors.Errorf("failed to inspect image: %w", err)
+		}
+
+		// Check if the actual platform matches the requested one
+		if inspectInfo.Architecture != archChoice || inspectInfo.Variant != variantChoice {
+			return RealImage{}, xerrors.Errorf(
+				"requested platform %s/%s/%s not available",
+				osChoice, archChoice, variantChoice,
+			)
+		}
+	}
+
 	return RealImage{
 		name:          originalName,
 		blobInfoCache: blobinfocache.DefaultCache(sys),

extractor/image/image_test.go

@@ -154,6 +154,20 @@ func TestNewImage(t *testing.T) {
 			},
 			wantErr: `failed to initialize: invalid character`,
 		},
+		{
+			name: "sad path: invalid platform variant",
+			args: args{
+				image: Reference{
+					Name:   "testdata/alpine-310.tar.gz",
+					IsFile: true,
+				},
+				transports: []string{"docker-archive:"},
+				option: types.DockerOption{
+					Platform: "linux/amd64/v99",
+				},
+			},
+			wantErr: `requested platform linux/amd64/v99 not available`,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {