Introduce package-wide CircularReferenceCounter to work around #615 (#628)

Co-authored-by: sorintm <[email protected]>

Author: fenollp

.github/workflows/go.yml

@@ -62,10 +62,10 @@ jobs:
     - run: git --no-pager diff --exit-code
 
     - if: runner.os == 'Linux'
-      run: go test ./...
+      run: go test -count=10 ./...
       env:
         GOARCH: '386'
-    - run: go test ./...
+    - run: go test -count=10 ./...
     - run: go test -count=2 -covermode=atomic ./...
     - run: go test -v -run TestRaceyPatternSchema -race ./...
       env:

openapi3/issue615_test.go

@@ -0,0 +1,33 @@
+package openapi3_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/getkin/kin-openapi/openapi3"
+)
+
+func TestIssue615(t *testing.T) {
+	for {
+		loader := openapi3.NewLoader()
+		loader.IsExternalRefsAllowed = true
+		_, err := loader.LoadFromFile("testdata/recursiveRef/issue615.yml")
+		if err == nil {
+			continue
+		}
+		// Test currently reproduces the issue 615: failure to load a valid spec
+		// Upon issue resolution, this check should be changed to require.NoError
+		require.Error(t, err, openapi3.CircularReferenceError)
+		break
+	}
+
+	var old int
+	old, openapi3.CircularReferenceCounter = openapi3.CircularReferenceCounter, 4
+	defer func() { openapi3.CircularReferenceCounter = old }()
+
+	loader := openapi3.NewLoader()
+	loader.IsExternalRefsAllowed = true
+	_, err := loader.LoadFromFile("testdata/recursiveRef/issue615.yml")
+	require.NoError(t, err)
+}

openapi3/loader.go

@@ -17,6 +17,7 @@ import (
 )
 
 var CircularReferenceError = "kin-openapi bug found: circular schema reference not handled"
+var CircularReferenceCounter = 3
 
 func foundUnresolvedRef(ref string) error {
 	return fmt.Errorf("found unresolved ref: %q", ref)
@@ -724,7 +725,7 @@ func (loader *Loader) resolveSchemaRef(doc *T, component *SchemaRef, documentPat
 			}
 			component.Value = &schema
 		} else {
-			if visitedLimit(visited, ref, 3) {
+			if visitedLimit(visited, ref) {
 				visited = append(visited, ref)
 				return fmt.Errorf("%s - %s", CircularReferenceError, strings.Join(visited, " -> "))
 			}
@@ -1088,12 +1089,12 @@ func unescapeRefString(ref string) string {
 	return strings.Replace(strings.Replace(ref, "~1", "/", -1), "~0", "~", -1)
 }
 
-func visitedLimit(visited []string, ref string, limit int) bool {
+func visitedLimit(visited []string, ref string) bool {
 	visitedCount := 0
 	for _, v := range visited {
 		if v == ref {
 			visitedCount++
-			if visitedCount >= limit {
+			if visitedCount >= CircularReferenceCounter {
 				return true
 			}
 		}

openapi3/testdata/recursiveRef/issue615.yml

@@ -0,0 +1,60 @@
+openapi: "3.0.3"
+info:
+  title: Deep recursive cyclic refs example
+  version: "1.0"
+paths:
+  /foo:
+    $ref: ./paths/foo.yml
+components:
+  schemas:
+    FilterColumnIncludes:
+      type: object
+      properties:
+        $includes:
+          $ref: '#/components/schemas/FilterPredicate'
+      additionalProperties: false
+      maxProperties: 1
+      minProperties: 1
+    FilterPredicate:
+      oneOf:
+        - $ref: '#/components/schemas/FilterValue'
+        - type: array
+          items:
+            $ref: '#/components/schemas/FilterPredicate'
+          minLength: 1
+        - $ref: '#/components/schemas/FilterPredicateOp'
+        - $ref: '#/components/schemas/FilterPredicateRangeOp'
+    FilterPredicateOp:
+      type: object
+      properties:
+        $any:
+          oneOf:
+            - type: array
+              items:
+                $ref: '#/components/schemas/FilterPredicate'
+        $none:
+          oneOf:
+            - $ref: '#/components/schemas/FilterPredicate'
+            - type: array
+              items:
+                $ref: '#/components/schemas/FilterPredicate'
+      additionalProperties: false
+      maxProperties: 1
+      minProperties: 1
+    FilterPredicateRangeOp:
+      type: object
+      properties:
+        $lt:
+          $ref: '#/components/schemas/FilterRangeValue'
+      additionalProperties: false
+      maxProperties: 2
+      minProperties: 2
+    FilterRangeValue:
+      oneOf:
+        - type: number
+        - type: string
+    FilterValue:
+      oneOf:
+        - type: number
+        - type: string
+        - type: boolean