[TT-16410] Validation fixes for OAS 3.1 from community

.github/docs/openapi3.txt

@@ -2401,6 +2401,11 @@ func EnableExamplesValidation() ValidationOption
     EnableExamplesValidation does the opposite of DisableExamplesValidation.
     By default, all schema examples are validated.
 
+func EnableJSONSchema2020Validation() ValidationOption
+    EnableJSONSchema2020Validation enables JSON Schema 2020-12 compliant
+    validation for OpenAPI 3.1 documents. This option should be used with
+    doc.Validate().
+
 func EnableSchemaDefaultsValidation() ValidationOption
     EnableSchemaDefaultsValidation does the opposite of
     DisableSchemaDefaultsValidation. By default, schema default values are

cmd/validate/main.go

@@ -68,6 +68,10 @@ func main() {
 		}
 
 		var opts []openapi3.ValidationOption
+		if doc.IsOpenAPI3_1() {
+			log.Println("Detected OpenAPI 3.1 document, enabling JSON Schema 2020-12 validation")
+			opts = append(opts, openapi3.EnableJSONSchema2020Validation())
+		}
 		if !*defaults {
 			opts = append(opts, openapi3.DisableSchemaDefaultsValidation())
 		}

openapi3/example_validation.go

@@ -5,11 +5,17 @@ import "context"
 func validateExampleValue(ctx context.Context, input any, schema *Schema) error {
 	opts := make([]SchemaValidationOption, 0, 2)
 
-	if vo := getValidationOptions(ctx); vo.examplesValidationAsReq {
+	vo := getValidationOptions(ctx)
+	if vo.examplesValidationAsReq {
 		opts = append(opts, VisitAsRequest())
 	} else if vo.examplesValidationAsRes {
 		opts = append(opts, VisitAsResponse())
 	}
+
+	if vo.jsonSchema2020ValidationEnabled {
+		opts = append(opts, EnableJSONSchema2020())
+	}
+
 	opts = append(opts, MultiErrors())
 
 	return schema.VisitJSON(input, opts...)

openapi3/refs.tmpl

@@ -1,4 +1,4 @@
-// Code generated by go generate; DO NOT EDIT.
+// Code generated by go generate using refs.tmpl; DO NOT EDIT refs.go.
 package {{ .Package }}
 
 import (
@@ -127,7 +127,13 @@ func (x *{{ $type.Name }}Ref) Validate(ctx context.Context, opts ...ValidationOp
 	}
 
 	if len(extras) != 0 {
+{{- if eq $type.Name "Schema" }}
+		if !getValidationOptions(ctx).jsonSchema2020ValidationEnabled {
+			return fmt.Errorf("extra sibling fields: %+v", extras)
+		}
+{{- else }}
 		return fmt.Errorf("extra sibling fields: %+v", extras)
+{{- end }}
 	}
 
 	if v := x.Value; v != nil {

openapi3/schema.go

@@ -1084,7 +1084,10 @@ func (schema *Schema) IsEmpty() bool {
 
 // Validate returns an error if Schema does not comply with the OpenAPI spec.
 func (schema *Schema) Validate(ctx context.Context, opts ...ValidationOption) error {
+	// Apply document-level validation options to the context
 	ctx = WithValidationOptions(ctx, opts...)
+
+	// Perform schema validation with the options in context
 	_, err := schema.validate(ctx, []*Schema{})
 	return err
 }
@@ -1206,6 +1209,10 @@ func (schema *Schema) validate(ctx context.Context, stack []*Schema) ([]*Schema,
 				return stack, errors.New("when schema type is 'array', schema 'items' must be non-null")
 			}
 		case TypeObject:
+		case TypeNull:
+			if !validationOpts.jsonSchema2020ValidationEnabled {
+				return stack, fmt.Errorf("unsupported 'type' value %q", schemaType)
+			}
 		default:
 			return stack, fmt.Errorf("unsupported 'type' value %q", schemaType)
 		}
@@ -1263,7 +1270,11 @@ func (schema *Schema) validate(ctx context.Context, stack []*Schema) ([]*Schema,
 	}
 
 	if v := schema.Default; v != nil && !validationOpts.schemaDefaultsValidationDisabled {
-		if err := schema.VisitJSON(v); err != nil {
+		opts := []SchemaValidationOption{}
+		if validationOpts.jsonSchema2020ValidationEnabled {
+			opts = append(opts, EnableJSONSchema2020())
+		}
+		if err := schema.VisitJSON(v, opts...); err != nil {
 			return stack, fmt.Errorf("invalid default: %w", err)
 		}
 	}

openapi3/validation_options.go

@@ -15,6 +15,7 @@ type ValidationOptions struct {
 	schemaExtensionsInRefProhibited                  bool
 	regexCompilerFunc                                RegexCompilerFunc
 	extraSiblingFieldsAllowed                        map[string]struct{}
+	jsonSchema2020ValidationEnabled                  bool // Enables JSON Schema 2020-12 compliant validation for OpenAPI 3.1
 }
 
 type validationOptionsKey struct{}
@@ -31,6 +32,14 @@ func AllowExtraSiblingFields(fields ...string) ValidationOption {
 	}
 }
 
+// EnableJSONSchema2020Validation enables JSON Schema 2020-12 compliant validation for OpenAPI 3.1 documents.
+// This option should be used with doc.Validate().
+func EnableJSONSchema2020Validation() ValidationOption {
+	return func(options *ValidationOptions) {
+		options.jsonSchema2020ValidationEnabled = true
+	}
+}
+
 // EnableSchemaFormatValidation makes Validate not return an error when validating documents that mention schema formats that are not defined by the OpenAPIv3 specification.
 // By default, schema format validation is disabled.
 func EnableSchemaFormatValidation() ValidationOption {