fix for resolving looping relative references

In vacuum, a usecase was reported where an infinite loop occurred due to re-parsing the same reference over and over in a loop. It was re-creatable and it was because the loop happened before the index was ready.

This should be resolved now, at least for this use case. To be sure, I have included the specs as a new test.

https://github.com/daveshanley/vacuum/issues/268
Signed-off-by: Dave Shanley <dave@quobix.com>

index/find_component_test.go

@@ -6,6 +6,7 @@ package index
 import (
 	"github.com/stretchr/testify/assert"
 	"gopkg.in/yaml.v3"
+	"os"
 	"testing"
 )
 
@@ -26,6 +27,22 @@ func TestSpecIndex_performExternalLookup(t *testing.T) {
 	assert.Len(t, index.GetPathsNode().Content, 1)
 }
 
+func TestSpecIndex_CheckCircularIndex(t *testing.T) {
+	yml, _ := os.ReadFile("../test_specs/first.yaml")
+	var rootNode yaml.Node
+	_ = yaml.Unmarshal([]byte(yml), &rootNode)
+
+	c := CreateOpenAPIIndexConfig()
+	c.BasePath = "../test_specs"
+	index := NewSpecIndexWithConfig(&rootNode, c)
+	assert.Nil(t, index.uri)
+	assert.NotNil(t, index.children[0].uri)
+	assert.NotNil(t, index.children[0].children[0].uri)
+	assert.NotNil(t, index.SearchIndexForReference("second.yaml#/properties/property2"))
+	assert.NotNil(t, index.SearchIndexForReference("second.yaml"))
+	assert.Nil(t, index.SearchIndexForReference("fourth.yaml"))
+}
+
 func TestSpecIndex_performExternalLookup_invalidURL(t *testing.T) {
 	yml := `openapi: 3.1.0
 components: