fix: changed JSON representation of inner conjunctions to always keep track of order

Within a session request, inner conjunctions requesting specific attribute values
used to be serialized to a map. JSON and Go maps are however unordered, and the
order matters: if the requested attributes are received in a different order then
the session will fail. Inner conjunctions using values are now serialized using
the default Go serializer, resulting in a list of requested attributes with their values.

irmago_test.go

@@ -311,9 +311,9 @@ func TestSessionRequests(t *testing.T) {
 						]
 					],
 					[
-						{
-							"irma-demo.MijnOverheid.fullName.firstname": "hello"
-						}
+						[
+							{ "type": "irma-demo.MijnOverheid.fullName.firstname", "value": "hello" }
+						]
 					]
 				],
 				"labels": {
@@ -366,9 +366,9 @@ func TestSessionRequests(t *testing.T) {
 						]
 					],
 					[
-						{
-							"irma-demo.MijnOverheid.fullName.firstname": "hello"
-						}
+						[
+							{ "type": "irma-demo.MijnOverheid.fullName.firstname", "value": "hello" }
+						]
 					]
 				],
 				"labels": {
@@ -438,9 +438,9 @@ func TestSessionRequests(t *testing.T) {
 						]
 					],
 					[
-						{
-							"irma-demo.MijnOverheid.fullName.firstname": "hello"
-						}
+						[
+							{ "type": "irma-demo.MijnOverheid.fullName.firstname", "value": "hello" }
+						]
 					]
 				],
 				"labels": {
@@ -478,19 +478,19 @@ func TestConDisconSingletons(t *testing.T) {
 			AttributeConDisCon{
 				AttributeDisCon{
 					AttributeCon{
-						NewAttributeRequest("irma-demo.RU.studentCard.studentID"), // singleton
-						NewAttributeRequest("test.test.email.email"),              // singleton
+						NewAttributeRequest("irma-demo.RU.studentCard.studentID"), // non singleton
+						NewAttributeRequest("test.test.email.email"),              // non singleton
 					},
 				},
 			},
-			false, // multiple singletons in one inner conjunction is not allowed
+			false, // multiple non-singletons in one inner conjunction is not allowed
 		},
 		{
 			AttributeConDisCon{
 				AttributeDisCon{
 					AttributeCon{
 						NewAttributeRequest("irma-demo.RU.studentCard.studentID"), // non singleton
-						NewAttributeRequest("test.test.mijnirma.email"),           // non singleton
+						NewAttributeRequest("test.test.mijnirma.email"),           // singleton
 					},
 				},
 			},
@@ -501,7 +501,7 @@ func TestConDisconSingletons(t *testing.T) {
 				AttributeDisCon{
 					AttributeCon{
 						NewAttributeRequest("irma-demo.MijnOverheid.root.BSN"), // singleton
-						NewAttributeRequest("test.test.mijnirma.email"),        // non singleton
+						NewAttributeRequest("test.test.mijnirma.email"),        // singleton
 					},
 				},
 			},

legacy.go

@@ -54,12 +54,24 @@ func checkType(typ, expected Action) error {
 
 // Reuses AttributeCon.UnmarshalJSON()
 func (l *legacyAttributeDisjunction) UnmarshalJSON(bts []byte) error {
-	var con AttributeCon
-	if err := json.Unmarshal(bts, &con); err != nil {
-		return err
+	var err error
+	var lst []AttributeTypeIdentifier
+	if err = json.Unmarshal(bts, &lst); err == nil {
+		for _, id := range lst {
+			*l = append(*l, AttributeRequest{Type: id})
+		}
+		return nil
 	}
-	*l = legacyAttributeDisjunction(con)
-	return nil
+
+	m := map[AttributeTypeIdentifier]*string{}
+	if err = json.Unmarshal(bts, &m); err == nil {
+		for id, val := range m {
+			*l = append(*l, AttributeRequest{Type: id, Value: val})
+		}
+		return nil
+	}
+
+	return errors.New("Failed to unmarshal legacy attribute conjunction")
 }
 
 func (dr *DisclosureRequest) UnmarshalJSON(bts []byte) (err error) {

requests.go

@@ -167,8 +167,8 @@ type DisclosureChoice struct {
 // An AttributeRequest asks for an instance of an attribute type, possibly requiring it to have
 // a specified value, in a session request.
 type AttributeRequest struct {
-	Type  AttributeTypeIdentifier
-	Value *string
+	Type  AttributeTypeIdentifier `json:"type"`
+	Value *string                 `json:"value"`
 }
 
 var (
@@ -224,20 +224,19 @@ func (c AttributeCon) Validate() error {
 
 func (c *AttributeCon) MarshalJSON() ([]byte, error) {
 	var vals bool
-	m := map[AttributeTypeIdentifier]*string{}
 	l := make([]AttributeTypeIdentifier, 0, len(*c))
 
 	for _, attr := range *c {
-		m[attr.Type] = attr.Value
 		if attr.Value == nil {
 			l = append(l, attr.Type)
 		} else {
 			vals = true
+			break
 		}
 	}
 
 	if vals {
-		return json.Marshal(m)
+		return json.Marshal((*[]AttributeRequest)(c))
 	} else {
 		return json.Marshal(l)
 	}
@@ -254,11 +253,7 @@ func (c *AttributeCon) UnmarshalJSON(bts []byte) error {
 		return nil
 	}
 
-	m := map[AttributeTypeIdentifier]*string{}
-	if err = json.Unmarshal(bts, &m); err == nil {
-		for id, val := range m {
-			*c = append(*c, AttributeRequest{Type: id, Value: val})
-		}
+	if err = json.Unmarshal(bts, (*[]AttributeRequest)(c)); err == nil {
 		return nil
 	}