fix: issue unmarshalling when discriminator field is set in openapi2.0

openapi2/issues1010_test.go

@@ -0,0 +1,97 @@
+package openapi2
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestIssue1010(t *testing.T) {
+	v2 := []byte(`
+{
+    "basePath": "/v2",
+    "host": "test.example.com",
+    "info": {
+        "title": "MyAPI",
+        "version": "0.1",
+        "x-info": "info extension"
+    },
+    "paths": {
+        "/foo": {
+            "get": {
+                "operationId": "getFoo",
+                "responses": {
+                    "200": {
+                        "description": "returns all information",
+                        "schema": {
+                            "$ref": "#/definitions/Pet"
+                        }
+                    },
+                    "default": {
+                        "description": "OK"
+                    }
+                },
+                "summary": "get foo"
+            }
+        }
+    },
+    "schemes": [
+        "http"
+    ],
+    "swagger": "2.0",
+    "definitions": {
+        "Pet": {
+            "type": "object",
+            "required": ["petType"],
+            "properties": {
+                "petType": {
+                    "type": "string"
+                },
+                "name": {
+                    "type": "string"
+                },
+                "age": {
+                    "type": "integer"
+                }
+            },
+            "discriminator": "petType"
+        },
+        "Dog": {
+            "allOf": [
+                {
+                    "$ref": "#/definitions/Pet"
+                },
+                {
+                    "type": "object",
+                    "properties": {
+                        "breed": {
+                            "type": "string"
+                        }
+                    }
+                }
+            ]
+        },
+        "Cat": {
+            "allOf": [
+                {
+                    "$ref": "#/definitions/Pet"
+                },
+                {
+                    "type": "object",
+                    "properties": {
+                        "color": {
+                            "type": "string"
+                        }
+                    }
+                }
+            ]
+        }
+    }
+}
+`)
+
+	var doc2 T
+	err := json.Unmarshal(v2, &doc2)
+	require.NoError(t, err)
+}

openapi3/discriminator_test.go

@@ -1,6 +1,7 @@
 package openapi3
 
 import (
+	"encoding/json"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -52,5 +53,15 @@ func TestParsingDiscriminator(t *testing.T) {
 	err = doc.Validate(loader.Context)
 	require.NoError(t, err)
 
-	require.Len(t, doc.Components.Schemas["MyResponseType"].Value.Discriminator.Mapping, 2)
+	discriminatorMap, ok := doc.Components.Schemas["MyResponseType"].Value.Discriminator.(map[string]interface{})
+	require.True(t, ok)
+
+	discriminatorBytes, err := json.Marshal(discriminatorMap)
+	require.NoError(t, err)
+
+	var discriminator *Discriminator
+	err = json.Unmarshal(discriminatorBytes, &discriminator)
+	require.NoError(t, err)
+
+	require.Len(t, discriminator.Mapping, 2)
 }

openapi3/schema.go

@@ -129,7 +129,7 @@ type Schema struct {
 	MinProps             uint64               `json:"minProperties,omitempty" yaml:"minProperties,omitempty"`
 	MaxProps             *uint64              `json:"maxProperties,omitempty" yaml:"maxProperties,omitempty"`
 	AdditionalProperties AdditionalProperties `json:"additionalProperties,omitempty" yaml:"additionalProperties,omitempty"`
-	Discriminator        *Discriminator       `json:"discriminator,omitempty" yaml:"discriminator,omitempty"`
+	Discriminator        interface{}          `json:"discriminator,omitempty" yaml:"discriminator,omitempty"`
 }
 
 type Types []string
@@ -1298,7 +1298,33 @@ func (schema *Schema) visitXOFOperations(settings *schemaValidationSettings, val
 	if v := schema.OneOf; len(v) > 0 {
 		var discriminatorRef string
 		if schema.Discriminator != nil {
-			pn := schema.Discriminator.PropertyName
+			var discriminator *Discriminator
+			if descriminatorValuemap, okcheck := schema.Discriminator.(map[string]any); okcheck {
+				marshaledDiscriminator, err := json.Marshal(descriminatorValuemap)
+				if err != nil {
+					return &SchemaError{
+						Schema:      schema,
+						SchemaField: "discriminator",
+						Reason:      fmt.Sprintf("unable to marshal the discriminator field in schema: %v", err),
+					}, false
+				}
+
+				if err := json.Unmarshal(marshaledDiscriminator, &discriminator); err != nil {
+					return &SchemaError{
+						Schema:      schema,
+						SchemaField: "discriminator",
+						Reason:      fmt.Sprintf("unable to unmarshall the discriminator field in schema: %v", err),
+					}, false
+				}
+			} else {
+				return &SchemaError{
+					Schema:      schema,
+					SchemaField: "discriminator",
+					Reason:      fmt.Sprintf("discriminator is expected to be an object, but received an unknown type"),
+				}, false
+			}
+
+			pn := discriminator.PropertyName
 			if valuemap, okcheck := value.(map[string]any); okcheck {
 				discriminatorVal, okcheck := valuemap[pn]
 				if !okcheck {
@@ -1319,7 +1345,7 @@ func (schema *Schema) visitXOFOperations(settings *schemaValidationSettings, val
 					}, false
 				}
 
-				if discriminatorRef, okcheck = schema.Discriminator.Mapping[discriminatorValString]; len(schema.Discriminator.Mapping) > 0 && !okcheck {
+				if discriminatorRef, okcheck = discriminator.Mapping[discriminatorValString]; len(discriminator.Mapping) > 0 && !okcheck {
 					return &SchemaError{
 						Value:       discriminatorVal,
 						Schema:      schema,
@@ -1328,6 +1354,7 @@ func (schema *Schema) visitXOFOperations(settings *schemaValidationSettings, val
 					}, false
 				}
 			}
+
 		}
 
 		var (