Return a more specific error when more than oneOf schemas match

openapi3/schema.go

@@ -25,6 +25,9 @@ var (
 
 	errSchema = errors.New("Input does not match the schema")
 
+	// ErrOneOfConflict is the SchemaError Origin when data matches more than one oneOf schema
+	ErrOneOfConflict = errors.New("input matches more than one oneOf schemas")
+
 	// ErrSchemaInputNaN may be returned when validating a number
 	ErrSchemaInputNaN = errors.New("NaN is not allowed")
 	// ErrSchemaInputInf may be returned when validating a number
@@ -851,11 +854,15 @@ func (schema *Schema) visitSetOperations(settings *schemaValidationSettings, val
 			if settings.failfast {
 				return errSchema
 			}
-			return &SchemaError{
+			e := &SchemaError{
 				Value:       value,
 				Schema:      schema,
 				SchemaField: "oneOf",
 			}
+			if ok > 1 {
+				e.Origin = ErrOneOfConflict
+			}
+			return e
 		}
 	}
 

openapi3/schema_issue289_test.go

@@ -0,0 +1,39 @@
+package openapi3
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestIssue289(t *testing.T) {
+	spec := []byte(`components:
+  schemas:
+    Server:
+      properties:
+        address:
+          oneOf:
+          - $ref: "#/components/schemas/ip-address"
+          - $ref: "#/components/schemas/domain-name"
+        name:
+          type: string
+      type: object
+    domain-name:
+      maxLength: 10
+      minLength: 5
+      pattern: "((([a-zA-Z0-9_]([a-zA-Z0-9\\-_]){0,61})?[a-zA-Z0-9]\\.)*([a-zA-Z0-9_]([a-zA-Z0-9\\-_]){0,61})?[a-zA-Z0-9]\\.?)|\\."
+      type: string
+    ip-address:
+      pattern: "^(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])$"
+      type: string
+openapi: "3.0.1"
+`)
+
+	s, err := NewSwaggerLoader().LoadSwaggerFromData(spec)
+	require.NoError(t, err)
+	err = s.Components.Schemas["Server"].Value.VisitJSON(map[string]interface{}{
+		"name":    "kin-openapi",
+		"address": "127.0.0.1",
+	})
+	require.EqualError(t, err, ErrOneOfConflict.Error())
+}