handle the main ref dereferencing issues (#229)

Signed-off-by: Pierre Fenoll <pierrefenoll@gmail.com>

Author: fenollp

openapi3/refs_test.go

@@ -0,0 +1,111 @@
+package openapi3
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestIssue222(t *testing.T) {
+	spec := `
+openapi: 3.0.0
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  license:
+    name: MIT
+servers:
+  - url: 'http://petstore.swagger.io/v1'
+paths:
+  /pets:
+    get:
+      summary: List all pets
+      operationId: listPets
+      tags:
+        - pets
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+            format: int32
+      responses:
+        '200': # <--------------- PANIC HERE
+
+    post:
+      summary: Create a pet
+      operationId: createPets
+      tags:
+        - pets
+      responses:
+        '201':
+          description: Null response
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+  '/pets/{petId}':
+    get:
+      summary: Info for a specific pet
+      operationId: showPetById
+      tags:
+        - pets
+      parameters:
+        - name: petId
+          in: path
+          required: true
+          description: The id of the pet to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Pet'
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+components:
+  schemas:
+    Pet:
+      type: object
+      required:
+        - id
+        - name
+      properties:
+        id:
+          type: integer
+          format: int64
+        name:
+          type: string
+        tag:
+          type: string
+    Pets:
+      type: array
+      items:
+        $ref: '#/components/schemas/Pet'
+    Error:
+      type: object
+      required:
+        - code
+        - message
+      properties:
+        code:
+          type: integer
+          format: int32
+        message:
+          type: string
+`
+
+	_, err := NewSwaggerLoader().LoadSwaggerFromData([]byte(spec))
+	require.EqualError(t, err, `invalid response: value MUST be a JSON object`)
+}

openapi3/swagger_loader.go

@@ -355,15 +355,16 @@ func (swaggerLoader *SwaggerLoader) resolveRefSwagger(swagger *Swagger, ref stri
 }
 
 func (swaggerLoader *SwaggerLoader) resolveHeaderRef(swagger *Swagger, component *HeaderRef, path *url.URL) error {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visited
 	if _, isVisited := visited[component]; isVisited {
 		return nil
 	}
 	visited[component] = struct{}{}
 
-	// Resolve ref
 	const prefix = "#/components/headers/"
+	if component == nil {
+		return errors.New("invalid header: value MUST be a JSON object")
+	}
 	if ref := component.Ref; len(ref) > 0 {
 		if isSingleRefElement(ref) {
 			var header Header
@@ -400,15 +401,16 @@ func (swaggerLoader *SwaggerLoader) resolveHeaderRef(swagger *Swagger, component
 }
 
 func (swaggerLoader *SwaggerLoader) resolveParameterRef(swagger *Swagger, component *ParameterRef, documentPath *url.URL) error {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visited
 	if _, isVisited := visited[component]; isVisited {
 		return nil
 	}
 	visited[component] = struct{}{}
 
-	// Resolve ref
 	const prefix = "#/components/parameters/"
+	if component == nil {
+		return errors.New("invalid parameter: value MUST be a JSON object")
+	}
 	ref := component.Ref
 	if len(ref) > 0 {
 		if isSingleRefElement(ref) {
@@ -461,15 +463,16 @@ func (swaggerLoader *SwaggerLoader) resolveParameterRef(swagger *Swagger, compon
 }
 
 func (swaggerLoader *SwaggerLoader) resolveRequestBodyRef(swagger *Swagger, component *RequestBodyRef, path *url.URL) error {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visited
 	if _, isVisited := visited[component]; isVisited {
 		return nil
 	}
 	visited[component] = struct{}{}
 
-	// Resolve ref
 	const prefix = "#/components/requestBodies/"
+	if component == nil {
+		return errors.New("invalid requestBody: value MUST be a JSON object")
+	}
 	if ref := component.Ref; len(ref) > 0 {
 		if isSingleRefElement(ref) {
 			var requestBody RequestBody
@@ -514,16 +517,17 @@ func (swaggerLoader *SwaggerLoader) resolveRequestBodyRef(swagger *Swagger, comp
 }
 
 func (swaggerLoader *SwaggerLoader) resolveResponseRef(swagger *Swagger, component *ResponseRef, documentPath *url.URL) error {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visited
 	if _, isVisited := visited[component]; isVisited {
 		return nil
 	}
 	visited[component] = struct{}{}
 
-	// Resolve ref
-	ref := component.Ref
 	const prefix = "#/components/responses/"
+	if component == nil {
+		return errors.New("invalid response: value MUST be a JSON object")
+	}
+	ref := component.Ref
 	if len(ref) > 0 {
 
 		if isSingleRefElement(ref) {
@@ -588,15 +592,16 @@ func (swaggerLoader *SwaggerLoader) resolveResponseRef(swagger *Swagger, compone
 }
 
 func (swaggerLoader *SwaggerLoader) resolveSchemaRef(swagger *Swagger, component *SchemaRef, documentPath *url.URL) error {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visited
 	if _, isVisited := visited[component]; isVisited {
 		return nil
 	}
 	visited[component] = struct{}{}
 
-	// Resolve ref
 	const prefix = "#/components/schemas/"
+	if component == nil {
+		return errors.New("invalid schema: value MUST be a JSON object")
+	}
 	ref := component.Ref
 	if len(ref) > 0 {
 		if isSingleRefElement(ref) {
@@ -673,15 +678,16 @@ func (swaggerLoader *SwaggerLoader) resolveSchemaRef(swagger *Swagger, component
 }
 
 func (swaggerLoader *SwaggerLoader) resolveSecuritySchemeRef(swagger *Swagger, component *SecuritySchemeRef, path *url.URL) error {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visited
 	if _, isVisited := visited[component]; isVisited {
 		return nil
 	}
 	visited[component] = struct{}{}
 
-	// Resolve ref
 	const prefix = "#/components/securitySchemes/"
+	if component == nil {
+		return errors.New("invalid securityScheme: value MUST be a JSON object")
+	}
 	if ref := component.Ref; len(ref) > 0 {
 		if isSingleRefElement(ref) {
 			var scheme SecurityScheme
@@ -709,14 +715,16 @@ func (swaggerLoader *SwaggerLoader) resolveSecuritySchemeRef(swagger *Swagger, c
 }
 
 func (swaggerLoader *SwaggerLoader) resolveExampleRef(swagger *Swagger, component *ExampleRef, path *url.URL) error {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visited
 	if _, isVisited := visited[component]; isVisited {
 		return nil
 	}
 	visited[component] = struct{}{}
 
 	const prefix = "#/components/examples/"
+	if component == nil {
+		return errors.New("invalid example: value MUST be a JSON object")
+	}
 	if ref := component.Ref; len(ref) > 0 {
 		if isSingleRefElement(ref) {
 			var example Example
@@ -744,14 +752,16 @@ func (swaggerLoader *SwaggerLoader) resolveExampleRef(swagger *Swagger, componen
 }
 
 func (swaggerLoader *SwaggerLoader) resolveLinkRef(swagger *Swagger, component *LinkRef, path *url.URL) error {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visited
 	if _, isVisited := visited[component]; isVisited {
 		return nil
 	}
 	visited[component] = struct{}{}
 
 	const prefix = "#/components/links/"
+	if component == nil {
+		return errors.New("invalid link: value MUST be a JSON object")
+	}
 	if ref := component.Ref; len(ref) > 0 {
 		if isSingleRefElement(ref) {
 			var link Link
@@ -779,7 +789,6 @@ func (swaggerLoader *SwaggerLoader) resolveLinkRef(swagger *Swagger, component *
 }
 
 func (swaggerLoader *SwaggerLoader) resolvePathItemRef(swagger *Swagger, entrypoint string, pathItem *PathItem, documentPath *url.URL) (err error) {
-	// Prevent infinite recursion
 	visited := swaggerLoader.visitedFiles
 	key := "_"
 	if documentPath != nil {
@@ -791,6 +800,10 @@ func (swaggerLoader *SwaggerLoader) resolvePathItemRef(swagger *Swagger, entrypo
 	}
 	visited[key] = struct{}{}
 
+	const prefix = "#/paths/"
+	if pathItem == nil {
+		return errors.New("invalid path item: value MUST be a JSON object")
+	}
 	ref := pathItem.Ref
 	if ref != "" {
 		if isSingleRefElement(ref) {
@@ -804,7 +817,6 @@ func (swaggerLoader *SwaggerLoader) resolvePathItemRef(swagger *Swagger, entrypo
 				return
 			}
 
-			prefix := "#/paths/"
 			if !strings.HasPrefix(ref, prefix) {
 				err = fmt.Errorf("expected prefix '%s' in URI '%s'", prefix, ref)
 				return