Ignore circular polymorphic ref.

motor/rule_applicator.go

@@ -67,7 +67,8 @@ type RuleSetExecution struct {
 	Timeout           time.Duration                 // The timeout for each rule to run, prevents run-away rules, default is five seconds.
 
 	// https://pb33f.io/libopenapi/circular-references/#circular-reference-results
-	IgnoreCircularArrayRef bool // Ignore array circular references
+	IgnoreCircularArrayRef       bool // Ignore array circular references
+	IgnoreCircularPolymorphicRef bool // Ignore polymorphic circular references
 }
 
 // RuleSetExecutionResult returns the results of running the ruleset against the supplied spec.
@@ -118,6 +119,10 @@ func ApplyRulesToRuleSet(execution *RuleSetExecution) *RuleSetExecutionResult {
 		docConfig.IgnoreArrayCircularReferences = true
 	}
 
+	if execution.IgnoreCircularPolymorphicRef {
+		docConfig.IgnorePolymorphicCircularReferences = true
+	}
+
 	// add new pretty logger.
 	if execution.Logger == nil {
 		var logger *slog.Logger

motor/rule_applicator_test.go

@@ -1930,6 +1930,57 @@ components:
 	assert.Len(t, results.Results, 0)
 }
 
+func TestRuleSet_InfiniteCircularLoop_AllowPolymorphicRecursion(t *testing.T) {
+	yml := `openapi: 3.1.0
+paths:
+  /one:
+    get:
+      responses:
+        '200':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/One'
+components:
+  schemas:
+    One:
+      properties:
+        thing:
+          oneOf:
+            - "$ref": "#/components/schemas/Two"
+            - "$ref": "#/components/schemas/Three"
+      required:
+        - thing
+    Two:
+      description: "test two"
+      properties:
+        testThing:
+          "$ref": "#/components/schemas/One"
+    Three:
+      description: "test three"
+      properties:
+        testThing:
+          "$ref": "#/components/schemas/One"`
+
+	rules := make(map[string]*model.Rule)
+	rules["openapi-tags-alphabetical"] = rulesets.GetOpenApiTagsAlphabeticalRule()
+
+	rs := &rulesets.RuleSet{
+		Rules: rules,
+	}
+
+	rse := &RuleSetExecution{
+		RuleSet:                      rs,
+		Spec:                         []byte(yml),
+		IgnoreCircularPolymorphicRef: true,
+	}
+	results := ApplyRulesToRuleSet(rse)
+	assert.Len(t, results.Errors, 0)
+
+	assert.NotNil(t, results)
+	assert.Len(t, results.Results, 0)
+}
+
 func TestApplyRules_TestRules_Custom_Document_Pattern(t *testing.T) {
 
 	yaml := `rules: