feat: extend unexpectedDataTypeError to describe multiple want types

Author: Adam Hughes

pkg/sif/descriptor.go

@@ -98,7 +98,7 @@ func (d *rawDescriptor) setExtra(v interface{}) error {
 // getPartitionMetadata gets metadata for a partition data object.
 func (d rawDescriptor) getPartitionMetadata() (fs FSType, pt PartType, arch string, err error) {
 	if got, want := d.DataType, DataPartition; got != want {
-		return 0, 0, "", &unexpectedDataTypeError{got, want}
+		return 0, 0, "", &unexpectedDataTypeError{got, []DataType{want}}
 	}
 
 	var p partition
@@ -188,7 +188,7 @@ func getHashType(ht hashType) (crypto.Hash, error) {
 // SignatureMetadata gets metadata for a signature data object.
 func (d Descriptor) SignatureMetadata() (ht crypto.Hash, fp []byte, err error) {
 	if got, want := d.raw.DataType, DataSignature; got != want {
-		return ht, fp, &unexpectedDataTypeError{got, want}
+		return ht, fp, &unexpectedDataTypeError{got, []DataType{want}}
 	}
 
 	var s signature
@@ -211,7 +211,7 @@ func (d Descriptor) SignatureMetadata() (ht crypto.Hash, fp []byte, err error) {
 // CryptoMessageMetadata gets metadata for a crypto message data object.
 func (d Descriptor) CryptoMessageMetadata() (FormatType, MessageType, error) {
 	if got, want := d.raw.DataType, DataCryptoMessage; got != want {
-		return 0, 0, &unexpectedDataTypeError{got, want}
+		return 0, 0, &unexpectedDataTypeError{got, []DataType{want}}
 	}
 
 	var m cryptoMessage

pkg/sif/descriptor_input.go

@@ -95,20 +95,49 @@ func OptObjectTime(t time.Time) DescriptorInputOpt {
 
 type unexpectedDataTypeError struct {
 	got  DataType
-	want DataType
+	want []DataType
 }
 
 func (e *unexpectedDataTypeError) Error() string {
-	return fmt.Sprintf("unexpected data type %v, expected %v", e.got, e.want)
+	return fmt.Sprintf("unexpected data type %v, expected one of: %v", e.got, e.want)
 }
 
 func (e *unexpectedDataTypeError) Is(target error) bool {
 	t, ok := target.(*unexpectedDataTypeError)
 	if !ok {
 		return false
 	}
-	return (e.got == t.got || t.got == 0) &&
-		(e.want == t.want || t.want == 0)
+
+	if len(t.want) > 0 {
+		// Use a map to check that the "want" errors in e and t contain the same values, ignoring
+		// any ordering differences.
+		acc := make(map[DataType]int, len(t.want))
+
+		// Increment counter for each data type in e.
+		for _, dt := range e.want {
+			if _, ok := acc[dt]; !ok {
+				acc[dt] = 0
+			}
+			acc[dt]++
+		}
+
+		// Decrement counter for each data type in e.
+		for _, dt := range t.want {
+			if _, ok := acc[dt]; !ok {
+				return false
+			}
+			acc[dt]--
+		}
+
+		// If the "want" errors in e and t are equivalent, all counters should be zero.
+		for _, n := range acc {
+			if n != 0 {
+				return false
+			}
+		}
+	}
+
+	return (e.got == t.got || t.got == 0)
 }
 
 // OptCryptoMessageMetadata sets metadata for a crypto message data object. The format type is set
@@ -118,7 +147,7 @@ func (e *unexpectedDataTypeError) Is(target error) bool {
 func OptCryptoMessageMetadata(ft FormatType, mt MessageType) DescriptorInputOpt {
 	return func(t DataType, opts *descriptorOpts) error {
 		if got, want := t, DataCryptoMessage; got != want {
-			return &unexpectedDataTypeError{got, want}
+			return &unexpectedDataTypeError{got, []DataType{want}}
 		}
 
 		m := cryptoMessage{
@@ -141,7 +170,7 @@ var errUnknownArchitcture = errors.New("unknown architecture")
 func OptPartitionMetadata(fs FSType, pt PartType, arch string) DescriptorInputOpt {
 	return func(t DataType, opts *descriptorOpts) error {
 		if got, want := t, DataPartition; got != want {
-			return &unexpectedDataTypeError{got, want}
+			return &unexpectedDataTypeError{got, []DataType{want}}
 		}
 
 		sifarch := getSIFArch(arch)
@@ -184,7 +213,7 @@ func sifHashType(h crypto.Hash) hashType {
 func OptSignatureMetadata(ht crypto.Hash, fp []byte) DescriptorInputOpt {
 	return func(t DataType, opts *descriptorOpts) error {
 		if got, want := t, DataSignature; got != want {
-			return &unexpectedDataTypeError{got, want}
+			return &unexpectedDataTypeError{got, []DataType{want}}
 		}
 
 		s := signature{

pkg/sif/descriptor_input_test.go

@@ -131,7 +131,7 @@ func TestNewDescriptorInput(t *testing.T) {
 			opts: []DescriptorInputOpt{
 				OptCryptoMessageMetadata(FormatOpenPGP, MessageClearSignature),
 			},
-			wantErr: &unexpectedDataTypeError{DataGeneric, DataCryptoMessage},
+			wantErr: &unexpectedDataTypeError{DataGeneric, []DataType{DataCryptoMessage}},
 		},
 		{
 			name: "OptCryptoMessageMetadata",
@@ -147,7 +147,7 @@ func TestNewDescriptorInput(t *testing.T) {
 			opts: []DescriptorInputOpt{
 				OptPartitionMetadata(FsSquash, PartPrimSys, "386"),
 			},
-			wantErr: &unexpectedDataTypeError{DataGeneric, DataPartition},
+			wantErr: &unexpectedDataTypeError{DataGeneric, []DataType{DataPartition}},
 		},
 		{
 			name: "OptPartitionMetadata",
@@ -163,7 +163,7 @@ func TestNewDescriptorInput(t *testing.T) {
 			opts: []DescriptorInputOpt{
 				OptSignatureMetadata(crypto.SHA256, fp),
 			},
-			wantErr: &unexpectedDataTypeError{DataGeneric, DataSignature},
+			wantErr: &unexpectedDataTypeError{DataGeneric, []DataType{DataSignature}},
 		},
 		{
 			name: "OptSignatureMetadata",

pkg/sif/descriptor_test.go

@@ -133,7 +133,7 @@ func TestDescriptor_PartitionMetadata(t *testing.T) {
 			rd: rawDescriptor{
 				DataType: DataGeneric,
 			},
-			wantErr: &unexpectedDataTypeError{DataGeneric, DataPartition},
+			wantErr: &unexpectedDataTypeError{DataGeneric, []DataType{DataPartition}},
 		},
 		{
 			name:     "PartPrimSys",
@@ -198,7 +198,7 @@ func TestDescriptor_SignatureMetadata(t *testing.T) {
 			rd: rawDescriptor{
 				DataType: DataGeneric,
 			},
-			wantErr: &unexpectedDataTypeError{DataGeneric, DataSignature},
+			wantErr: &unexpectedDataTypeError{DataGeneric, []DataType{DataSignature}},
 		},
 		{
 			name:   "OK",
@@ -258,7 +258,7 @@ func TestDescriptor_CryptoMessageMetadata(t *testing.T) {
 			rd: rawDescriptor{
 				DataType: DataGeneric,
 			},
-			wantErr: &unexpectedDataTypeError{DataGeneric, DataCryptoMessage},
+			wantErr: &unexpectedDataTypeError{DataGeneric, []DataType{DataCryptoMessage}},
 		},
 		{
 			name:   "OK",