Fix resolveSchemaRef() to load correctly an other spec. file refere…

…nced by `$ref` (#583)

openapi3/load_cicular_ref_with_external_file_test.go

@@ -0,0 +1,82 @@
+//go:build go1.16
+// +build go1.16
+
+package openapi3_test
+
+import (
+	"embed"
+	"net/url"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/getkin/kin-openapi/openapi3"
+)
+
+//go:embed testdata/circularRef/*
+var circularResSpecs embed.FS
+
+func TestLoadCircularRefFromFile(t *testing.T) {
+	loader := openapi3.NewLoader()
+	loader.IsExternalRefsAllowed = true
+	loader.ReadFromURIFunc = func(loader *openapi3.Loader, uri *url.URL) ([]byte, error) {
+		return circularResSpecs.ReadFile(uri.Path)
+	}
+
+	got, err := loader.LoadFromFile("testdata/circularRef/base.yml")
+	if err != nil {
+		t.Error(err)
+	}
+
+	foo := &openapi3.SchemaRef{
+		Ref: "",
+		Value: &openapi3.Schema{
+			ExtensionProps: openapi3.ExtensionProps{Extensions: map[string]interface{}{}},
+			Properties: map[string]*openapi3.SchemaRef{
+				"foo2": { // reference to an external file
+					Ref: "other.yml#/components/schemas/Foo2",
+					Value: &openapi3.Schema{
+						ExtensionProps: openapi3.ExtensionProps{Extensions: map[string]interface{}{}},
+						Properties: map[string]*openapi3.SchemaRef{
+							"id": {
+								Value: &openapi3.Schema{
+									Type:           "string",
+									ExtensionProps: openapi3.ExtensionProps{Extensions: map[string]interface{}{}},
+								}},
+						},
+					},
+				},
+			},
+		},
+	}
+	bar := &openapi3.SchemaRef{
+		Ref: "",
+		Value: &openapi3.Schema{
+			ExtensionProps: openapi3.ExtensionProps{Extensions: map[string]interface{}{}},
+			Properties:     map[string]*openapi3.SchemaRef{},
+		},
+	}
+	// circular reference
+	bar.Value.Properties["foo"] = &openapi3.SchemaRef{Ref: "#/components/schemas/Foo", Value: foo.Value}
+	foo.Value.Properties["bar"] = &openapi3.SchemaRef{Ref: "#/components/schemas/Bar", Value: bar.Value}
+
+	want := &openapi3.T{
+		OpenAPI: "3.0.3",
+		Info: &openapi3.Info{
+			Title:   "Recursive cyclic refs example",
+			Version: "1.0",
+
+			ExtensionProps: openapi3.ExtensionProps{Extensions: map[string]interface{}{}},
+		},
+		Components: openapi3.Components{
+			ExtensionProps: openapi3.ExtensionProps{Extensions: map[string]interface{}{}},
+			Schemas: map[string]*openapi3.SchemaRef{
+				"Foo": foo,
+				"Bar": bar,
+			},
+		},
+		ExtensionProps: openapi3.ExtensionProps{Extensions: map[string]interface{}{}},
+	}
+
+	require.Equal(t, want, got)
+}

openapi3/loader.go

@@ -699,7 +699,8 @@ func (loader *Loader) resolveSchemaRef(doc *T, component *SchemaRef, documentPat
 				return err
 			}
 			component.Value = resolved.Value
-			documentPath = loader.documentPathForRecursiveRef(documentPath, resolved.Ref)
+			foundPath := loader.getResolvedRefPath(ref, &resolved, documentPath, componentPath)
+			documentPath = loader.documentPathForRecursiveRef(documentPath, foundPath)
 		}
 	}
 	value := component.Value
@@ -746,6 +747,22 @@ func (loader *Loader) resolveSchemaRef(doc *T, component *SchemaRef, documentPat
 	return nil
 }
 
+func (loader *Loader) getResolvedRefPath(ref string, resolved *SchemaRef, cur, found *url.URL) string {
+	referencedFilename := strings.Split(ref, "#")[0]
+	if referencedFilename == "" {
+		if cur != nil {
+			return path.Base(cur.Path)
+		}
+		return ""
+	}
+	// ref. to external file
+	if resolved.Ref != "" {
+		return resolved.Ref
+	}
+	// found dest spec. file
+	return path.Dir(found.Path)[len(loader.rootDir):]
+}
+
 func (loader *Loader) resolveSecuritySchemeRef(doc *T, component *SecuritySchemeRef, documentPath *url.URL) (err error) {
 	if component != nil && component.Value != nil {
 		if loader.visitedSecurityScheme == nil {

openapi3/testdata/circularRef/base.yml

@@ -0,0 +1,16 @@
+openapi: "3.0.3"
+info:
+  title: Recursive cyclic refs example
+  version: "1.0"
+components:
+  schemas:
+    Foo:
+      properties:
+        foo2:
+          $ref: "other.yml#/components/schemas/Foo2"
+        bar:
+          $ref: "#/components/schemas/Bar"
+    Bar:
+      properties:
+        foo:
+          $ref: "#/components/schemas/Foo"

openapi3/testdata/circularRef/other.yml

@@ -0,0 +1,10 @@
+openapi: "3.0.3"
+info:
+  title: Recursive cyclic refs example
+  version: "1.0"
+components:
+  schemas:
+    Foo2:
+      properties:
+        id:
+          type: string