add proper schema validation handling.

Author: daveshanley

helpers/schema_compiler.go

@@ -55,8 +55,7 @@ func NewCompiledSchema(name string, jsonSchema []byte, o *config.ValidationOptio
 // - version 3.0: Allows OpenAPI 3.0 keywords like 'nullable'
 // - version 3.1+: Rejects OpenAPI 3.0 keywords like 'nullable' (strict JSON Schema compliance)
 func NewCompiledSchemaWithVersion(name string, jsonSchema []byte, o *config.ValidationOptions, version float32) (*jsonschema.Schema, error) {
-	// fake-Up a resource name for the schema
-	resourceName := fmt.Sprintf("%s.json", name)
+	resourceName := fmt.Sprintf("%s", name)
 
 	compiler := NewCompilerWithOptions(o)
 	compiler.UseLoader(NewCompilerLoader())
@@ -94,7 +93,7 @@ func NewCompiledSchemaWithVersion(name string, jsonSchema []byte, o *config.Vali
 
 	jsch, err := compiler.Compile(resourceName)
 	if err != nil {
-		return nil, fmt.Errorf("failed to compile JSON schema: %w", err)
+		return nil, fmt.Errorf("JSON schema compile failed: %s", err.Error())
 	}
 
 	return jsch, nil

responses/validate_body_test.go

@@ -1364,7 +1364,7 @@ components:
 
 	assert.False(t, valid)
 	assert.Len(t, errors, 1)
-	assert.Equal(t, "cannot render circular reference: #/components/schemas/Error", errors[0].Reason)
+	assert.Equal(t, "schema render failure, circular reference: `#/components/schemas/Error`", errors[0].Reason)
 }
 
 func TestValidateBody_CheckHeader(t *testing.T) {

schema_validation/validate_schema.go

@@ -129,7 +129,31 @@ func (s *schemaValidator) validateSchemaWithVersion(schema *base.Schema, payload
 	// render the schema, to be used for validation, stop this from running concurrently, mutations are made to state
 	// and, it will cause async issues.
 	s.lock.Lock()
-	renderedSchema, _ = schema.RenderInline()
+	var e error
+	renderedSchema, e = schema.RenderInline()
+	if e != nil {
+		// schema cannot be rendered, so it's not valid!
+		violation := &liberrors.SchemaValidationFailure{
+			Reason:          e.Error(),
+			Location:        "unavailable",
+			ReferenceSchema: string(renderedSchema),
+			ReferenceObject: string(payload),
+		}
+		validationErrors = append(validationErrors, &liberrors.ValidationError{
+			ValidationType:         helpers.RequestBodyValidation,
+			ValidationSubType:      helpers.Schema,
+			Message:                "schema does not pass validation",
+			Reason:                 fmt.Sprintf("The schema cannot be decoded: %s", e.Error()),
+			SpecLine:               schema.GoLow().GetRootNode().Line,
+			SpecCol:                schema.GoLow().GetRootNode().Column,
+			SchemaValidationErrors: []*liberrors.SchemaValidationFailure{violation},
+			HowToFix:               liberrors.HowToFixInvalidSchema,
+			Context:                string(renderedSchema),
+		})
+		s.lock.Unlock()
+		return false, validationErrors
+
+	}
 	s.lock.Unlock()
 
 	jsonSchema, _ := utils.ConvertYAMLtoJSON(renderedSchema)
@@ -145,23 +169,29 @@ func (s *schemaValidator) validateSchemaWithVersion(schema *base.Schema, payload
 				ReferenceSchema: string(renderedSchema),
 				ReferenceObject: string(payload),
 			}
+			line := 1
+			col := 0
+			if schema.GoLow().Type.KeyNode != nil {
+				line = schema.GoLow().Type.KeyNode.Line
+				col = schema.GoLow().Type.KeyNode.Column
+			}
 			validationErrors = append(validationErrors, &liberrors.ValidationError{
 				ValidationType:         helpers.RequestBodyValidation,
 				ValidationSubType:      helpers.Schema,
 				Message:                "schema does not pass validation",
 				Reason:                 fmt.Sprintf("The schema cannot be decoded: %s", err.Error()),
-				SpecLine:               1,
-				SpecCol:                0,
+				SpecLine:               line,
+				SpecCol:                col,
 				SchemaValidationErrors: []*liberrors.SchemaValidationFailure{violation},
 				HowToFix:               liberrors.HowToFixInvalidSchema,
-				Context:                string(renderedSchema), // attach the rendered schema to the error
+				Context:                string(renderedSchema),
 			})
 			return false, validationErrors
 		}
 
 	}
 
-	jsch, err := helpers.NewCompiledSchemaWithVersion("schema", jsonSchema, s.options, version)
+	jsch, err := helpers.NewCompiledSchemaWithVersion(schema.GoLow().GetIndex().GetSpecAbsolutePath(), jsonSchema, s.options, version)
 
 	var schemaValidationErrors []*liberrors.SchemaValidationFailure
 	if err != nil {
@@ -171,16 +201,22 @@ func (s *schemaValidator) validateSchemaWithVersion(schema *base.Schema, payload
 			ReferenceSchema: string(renderedSchema),
 			ReferenceObject: string(payload),
 		}
+		line := 1
+		col := 0
+		if schema.GoLow().Type.KeyNode != nil {
+			line = schema.GoLow().Type.KeyNode.Line
+			col = schema.GoLow().Type.KeyNode.Column
+		}
 		validationErrors = append(validationErrors, &liberrors.ValidationError{
 			ValidationType:         helpers.Schema,
 			ValidationSubType:      helpers.Schema,
 			Message:                "schema compilation failed",
 			Reason:                 fmt.Sprintf("Schema compilation failed: %s", err.Error()),
-			SpecLine:               1,
-			SpecCol:                0,
+			SpecLine:               line,
+			SpecCol:                col,
 			SchemaValidationErrors: []*liberrors.SchemaValidationFailure{violation},
 			HowToFix:               liberrors.HowToFixInvalidSchema,
-			Context:                string(renderedSchema), // attach the rendered schema to the error
+			Context:                string(renderedSchema),
 		})
 		return false, validationErrors
 	}
@@ -212,7 +248,7 @@ func (s *schemaValidator) validateSchemaWithVersion(schema *base.Schema, payload
 				SpecCol:                col,
 				SchemaValidationErrors: schemaValidationErrors,
 				HowToFix:               liberrors.HowToFixInvalidSchema,
-				Context:                string(renderedSchema), // attach the rendered schema to the error
+				Context:                string(renderedSchema),
 			})
 		}
 	}

schema_validation/validate_schema_openapi_test.go

@@ -277,6 +277,151 @@ paths:
 	assert.Empty(t, errors, "Should have no validation errors")
 }
 
+func TestValidateSchema_CircularReference(t *testing.T) {
+	spec := `openapi: "3.1.0"
+info:
+  title: Test
+  version: "1"
+paths:
+  /:
+    post:
+      operationId: op
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/c'
+components:
+  schemas:
+    a:
+      type: "string"
+      examples:
+       - ''
+    b:
+      type: "object"
+      examples:
+        - { "z": "" }
+      properties:
+        z:
+          "$ref": '#/components/schemas/a'
+        b:
+          "$ref": '#/components/schemas/b'
+    c:
+      type: "object"
+      examples:
+        - { "b": { "z": "" } }
+      properties:
+        "b":
+          "$ref": '#/components/schemas/b'`
+
+	doc, err := libopenapi.NewDocument([]byte(spec))
+	assert.NoError(t, err)
+
+	model, errs := doc.BuildV3Model()
+	assert.Nil(t, errs)
+
+	schema := model.Model.Paths.PathItems.GetOrZero("/").Post.RequestBody.Content.GetOrZero("application/json").Schema
+	assert.NotNil(t, schema)
+	assert.NotNil(t, schema.Schema())
+
+	t.Run("should fail rendering", func(t *testing.T) {
+		_, err := schema.Schema().RenderInline()
+		assert.Error(t, err, "RenderInline should not error on circular refs")
+
+	})
+
+	t.Run("should fail validating", func(t *testing.T) {
+		sv := NewSchemaValidator()
+
+		schemaB := model.Model.Components.Schemas.GetOrZero("b").Schema()
+
+		assert.NotNil(t, schemaB)
+		assert.NotNil(t, schemaB.Examples)
+
+		exampleJSON := `{"z": "", "b": {"z": ""}}`
+		valid, errors := sv.ValidateSchemaString(schemaB, exampleJSON)
+
+		assert.False(t, valid, "Schema with circular refs should currently fail validation")
+		assert.NotNil(t, errors, "Should have validation errors")
+
+		foundCompilationError := false
+		for _, err := range errors {
+			if err.SchemaValidationErrors != nil {
+				for _, schErr := range err.SchemaValidationErrors {
+					if schErr.Location == "unavailable" && schErr.Reason == "schema render failure, circular reference: `#/components/schemas/b`" {
+						foundCompilationError = true
+					}
+				}
+			}
+		}
+		assert.True(t, foundCompilationError, "Should have schema compilation error for circular references")
+	})
+}
+
+func TestValidateSchema_SimpleCircularReference(t *testing.T) {
+	// Even simpler test case
+	spec := `openapi: "3.1.0"
+info:
+  title: Test
+  version: "1"
+paths:
+  /test:
+    get:
+      responses:
+        '200':
+          description: OK
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Node'
+components:
+  schemas:
+    Node:
+      type: object
+      properties:
+        value:
+          type: string
+        next:
+          $ref: '#/components/schemas/Node'
+      examples:
+        - value: "test"
+          next:
+            value: "nested"`
+
+	doc, err := libopenapi.NewDocument([]byte(spec))
+	assert.NoError(t, err)
+
+	model, errs := doc.BuildV3Model()
+	assert.Nil(t, errs)
+
+	schema := model.Model.Paths.PathItems.GetOrZero("/test").Get.Responses.Codes.GetOrZero("200").Content.GetOrZero("application/json").Schema
+	assert.NotNil(t, schema)
+	assert.NotNil(t, schema.Schema())
+
+	// Try to render inline
+	rendered, err := schema.Schema().RenderInline()
+	if err != nil {
+		t.Logf("RenderInline error on simple circular ref: %v", err)
+	} else {
+		t.Logf("RenderInline succeeded for simple circular ref, rendered %d bytes", len(rendered))
+	}
+
+	// Validate using schema validator
+	sv := NewSchemaValidator()
+	nodeSchema := model.Model.Components.Schemas.GetOrZero("Node").Schema()
+
+	// Try to validate an example against the schema
+	exampleJSON := `{"value": "test", "next": {"value": "nested"}}`
+	valid, errors := sv.ValidateSchemaString(nodeSchema, exampleJSON)
+
+	t.Logf("Simple circular ref - Schema validation valid: %v", valid)
+	if errors != nil {
+		for _, err := range errors {
+			t.Logf("Error: %s", err.Error())
+		}
+	}
+}
+
 // Helper function to check if a string contains a substring (case-insensitive)
 func contains(s, substr string) bool {
 	return len(s) >= len(substr) && (s == substr || len(substr) == 0 ||

validator_test.go

@@ -1829,7 +1829,7 @@ components:
 	}
 	if ok, errs := oapiValidator.ValidateHttpResponse(req, res); !ok {
 		assert.Equal(t, 1, len(errs))
-		assert.Equal(t, "cannot render circular reference: #/components/schemas/Error", errs[0].Reason)
+		assert.Equal(t, "schema render failure, circular reference: `#/components/schemas/Error`", errs[0].Reason)
 
 	}
 }