fix: output for recursive refs

.changeset/allof-recursive-ref.md

@@ -0,0 +1,5 @@
+---
+"openapi-sampler": patch
+---
+
+Fixed a regression from 1.7.8 where a recursive `$ref` inside `allOf` was sampled as `null` instead of an empty object.

src/allOf.js

@@ -7,7 +7,7 @@ export function allOfSample(into, children, options, spec, context) {
   const subSamples = [];
 
   for (let subSchema of children) {
-    const childSchema = subSchema.$ref ? subSchema : { type: res.type, ...subSchema };
+    const childSchema = subSchema.$ref ? { ...subSchema } : { type: res.type, ...subSchema };
     const { type, readOnly, writeOnly, value } = traverse(childSchema, options, spec, {
       ...context,
       isAllOfChild: true,

test/integration.spec.js

@@ -608,7 +608,7 @@
         type: 'object',
         properties: { top: { type: 'number' } },
         if: { properties: { foo: { type: 'string', format: 'email' } } },
         then: { properties: { bar: { type: 'string' } } },
         else: { properties: { baz: { type: 'number' } } },
       };
 
@@ -745,7 +745,7 @@
           }
         ],
         if: { properties: { foo: { type: 'string', format: 'email' } } },
         then: { properties: { bar: { type: 'string' } } },
         else: { properties: { baz: { type: 'number' } } },
       };
 
@@ -960,6 +960,27 @@
         }
       });
 
+      it('should sample a recursive $ref inside allOf as an empty object', () => {
+        for (const version of [{ openapi: '3.0.0' }, { openapi: '3.1.0' }]) {
+          const spec = {
+            ...version,
+            components: {
+              schemas: {
+                Node: {
+                  type: 'object',
+                  properties: {
+                    name: { type: 'string' },
+                    child: { allOf: [{ $ref: '#/components/schemas/Node' }] },
+                  },
+                },
+              },
+            },
+          };
+          result = sample(spec.components.schemas.Node, {}, spec);
+          expect(result).toEqual({ name: 'string', child: { name: 'string', child: {} } });
+        }
+      });
+
       it('should keep readOnly and writeOnly of a $ref in oneOf and anyOf', () => {
         for (const version of [{ openapi: '3.1.0' }, {}]) {
           const spec = {