Fix #1154

Immediately exit from allOf's children, but use separate refCounter to do not enter into same scheme recursively
Also add pseudo-recursive example

demo/pseudo-recursive.yaml

@@ -0,0 +1,58 @@
+openapi: 3.0.0
+info:
+  title: False positive recursion
+  version: '3.0'
+tags:
+  - name: a
+
+components:
+  schemas:
+    id:
+      tags:
+        - a
+      type: object
+      properties:
+        id:
+          type: number
+          description: id
+    pet:
+      tags:
+        - a
+      type: object
+      properties:
+        name:
+          type: string
+        friends:
+          type: array
+          items:
+            allOf:
+              - $ref: '#/components/schemas/pet'
+paths:
+  /documents:
+    get:
+      summary: Example
+      responses:
+        '200':
+          description: Pseudo-recursvie
+          content:
+            application/json:
+              schema:
+                allOf:
+                  - $ref: '#/components/schemas/id'
+                  - properties:
+                      second:
+                        allOf:
+                          - $ref: '#/components/schemas/id'
+                          - properties:
+                              third:
+                                allOf:
+                                  - $ref: '#/components/schemas/id'
+                                  - properties:
+                                      something:
+                                        type: string
+        '204':
+          description: Recursvie
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/pet'

src/services/OpenAPIParser.ts

@@ -18,7 +18,7 @@ export type MergedOpenAPISchema = OpenAPISchema & { parentRefs?: string[] };
  * Helper class to keep track of visited references to avoid
  * endless recursion because of circular refs
  */
-class RefCounter {
+export class RefCounter {
   _counter = {};
 
   reset(): void {
@@ -46,6 +46,8 @@ export class OpenAPIParser {
   spec: OpenAPISpec;
   mergeRefs: Set<string>;
 
+  schemaCounter: RefCounter = new RefCounter();
+
   private _refCounter: RefCounter = new RefCounter();
 
   constructor(
@@ -221,6 +223,7 @@ export class OpenAPIParser {
 
         const resolved = this.deref(subSchema, forceCircular);
         const subRef = subSchema.$ref || undefined;
+        this.exitRef(subSchema);
         const subMerged = this.mergeAllOf(resolved, subRef, forceCircular, used$Refs);
         receiver.parentRefs!.push(...(subMerged.parentRefs || []));
         return {
@@ -311,8 +314,8 @@ export class OpenAPIParser {
     return res;
   }
 
-  exitParents(shema: MergedOpenAPISchema) {
-    for (const parent$ref of shema.parentRefs || []) {
+  exitParents(schema: MergedOpenAPISchema) {
+    for (const parent$ref of schema.parentRefs || []) {
       this.exitRef({ $ref: parent$ref });
     }
   }

src/services/models/Schema.ts

@@ -2,7 +2,7 @@ import { action, observable } from 'mobx';
 
 import { OpenAPIExternalDocumentation, OpenAPISchema, Referenced } from '../../types';
 
-import { OpenAPIParser } from '../OpenAPIParser';
+import {OpenAPIParser, RefCounter} from '../OpenAPIParser';
 import { RedocNormalizedOptions } from '../RedocNormalizedOptions';
 import { FieldModel } from './Field';
 
@@ -21,6 +21,8 @@ import {
 
 import { l } from '../Labels';
 
+const schemaCounter = new RefCounter();
+
 // TODO: refactor this model, maybe use getters instead of copying all the values
 export class SchemaModel {
   pointer: string;
@@ -73,16 +75,26 @@ export class SchemaModel {
     isChild: boolean = false,
   ) {
     this.pointer = schemaOrRef.$ref || pointer || '';
-    this.rawSchema = parser.deref(schemaOrRef);
-    this.schema = parser.mergeAllOf(this.rawSchema, this.pointer, isChild);
+    let visited = false;
+    if (this.pointer) {
+      visited = schemaCounter.visited(this.pointer);
+      schemaCounter.visit(this.pointer);
+    }
+    if (!visited) {
+      this.rawSchema = parser.deref(schemaOrRef);
+      this.schema = parser.mergeAllOf(this.rawSchema, this.pointer, isChild);
 
-    this.init(parser, isChild);
+      this.init(parser, isChild);
 
-    parser.exitRef(schemaOrRef);
-    parser.exitParents(this.schema);
+      parser.exitRef(schemaOrRef);
+      parser.exitParents(this.schema);
 
-    if (options.showExtensions) {
-      this.extensions = extractExtensions(this.schema, options.showExtensions);
+      if (options.showExtensions) {
+        this.extensions = extractExtensions(this.schema, options.showExtensions);
+      }
+    }
+    if (this.pointer) {
+      schemaCounter.exit(this.pointer);
     }
   }