Correctly resolve path of yaml resource if double referenced.

Where previously following path was resolved `testdata/components/models/error.yaml`, missing `recursiveRef` folder.

 Author:    davor.sauer <davor.sauer@gmail.com>

openapi3/loader.go

@@ -249,7 +249,14 @@ func join(basePath *url.URL, relativePath *url.URL) (*url.URL, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot copy path: %q", basePath.String())
 	}
-	newPath.Path = path.Join(path.Dir(newPath.Path), relativePath.Path)
+
+	// check if basePath is reference to the file
+	if strings.LastIndex(basePath.Path, ".") > strings.LastIndex(basePath.Path, "/") {
+		newPath.Path = path.Join(path.Dir(newPath.Path), relativePath.Path)
+	} else {
+		newPath.Path = path.Join(newPath.Path, relativePath.Path)
+	}
+
 	return newPath, nil
 }
 
@@ -421,10 +428,6 @@ func (loader *Loader) documentPathForRecursiveRef(current *url.URL, resolvedRef
 		return current
 	}
 
-	if resolvedRef == "" {
-		return current
-	}
-
 	return &url.URL{Path: path.Join(loader.rootDir, resolvedRef)}
 }
 

openapi3/loader_recursive_ref_test.go

@@ -1,11 +1,28 @@
 package openapi3
 
 import (
+	"net/url"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
+func TestResolvePath(t *testing.T) {
+	var b = &url.URL{Path: "testdata/recursiveRef"}
+	var c = &url.URL{Path: "./components/models/error.yaml"}
+	u, err := resolvePath(b, c)
+
+	require.NoError(t, err)
+	require.Equal(t, &url.URL{Path: "testdata/recursiveRef/components/models/error.yaml"}, u)
+
+	b = &url.URL{Path: "testdata/recursiveRef/openapi.yaml"}
+	c = &url.URL{Path: "./components/models/error.yaml"}
+	u, err = resolvePath(b, c)
+
+	require.NoError(t, err)
+	require.Equal(t, &url.URL{Path: "testdata/recursiveRef/components/models/error.yaml"}, u)
+}
+
 func TestLoaderSupportsRecursiveReference(t *testing.T) {
 	loader := NewLoader()
 	loader.IsExternalRefsAllowed = true

openapi3/testdata/recursiveRef/openapi.yml

@@ -30,4 +30,4 @@ components:
       content:
         application/json:
           schema:
-            $ref: "#/components/schemas/Error"
+            $ref: "#/components/schemas/Error"