fix: make getters convert uuid to string when calling toObject() and toJSON()

lib/schema/uuid.js

@@ -26,19 +26,6 @@ function hex2buffer(hex) {
   return buff;
 }
 
-/**
- * Helper function to convert the buffer input to a string
- * @param {Buffer} buf The buffer to convert to a hex-string
- * @returns {String} The buffer as a hex-string
- * @api private
- */
-
-function binary2hex(buf) {
-  // use buffer built-in function to convert from buffer to hex-string
-  const hex = buf != null && buf.toString('hex');
-  return hex;
-}
-
 /**
  * Convert a String to Binary
  * @param {String} uuidStr The value to process
@@ -67,7 +54,7 @@ function binaryToString(uuidBin) {
   // i(hasezoey) dont quite know why, but "uuidBin" may sometimes also be the already processed string
   let hex;
   if (typeof uuidBin !== 'string' && uuidBin != null) {
-    hex = binary2hex(uuidBin);
+    hex = uuidBin.toString('hex');
     const uuidStr = hex.substring(0, 8) + '-' + hex.substring(8, 8 + 4) + '-' + hex.substring(12, 12 + 4) + '-' + hex.substring(16, 16 + 4) + '-' + hex.substring(20, 20 + 12);
     return uuidStr;
   }
@@ -90,7 +77,15 @@ function SchemaUUID(key, options) {
     if (value != null && value.$__ != null) {
       return value;
     }
-    return binaryToString(value);
+    if (Buffer.isBuffer(value)) {
+      return binaryToString(value);
+    } else if (value instanceof Binary) {
+      return binaryToString(value.buffer);
+    } else if (utils.isPOJO(value) && value.type === 'Buffer' && Array.isArray(value.data)) {
+      // Cloned buffers look like `{ type: 'Buffer', data: [5, 224, ...] }`
+      return binaryToString(Buffer.from(value.data));
+    }
+    return value;
   });
 }
 

test/model.populate.test.js

@@ -11131,4 +11131,41 @@ describe('model: populate:', function() {
     }
     assert.equal(posts.length, 2);
   });
+
+  it('handles converting uuid documents to strings when calling toObject() (gh-14869)', async function() {
+    const nodeSchema = new Schema({ _id: { type: 'UUID' }, name: 'String' });
+    const rootSchema = new Schema({
+      _id: { type: 'UUID' },
+      status: 'String',
+      node: [{ type: 'UUID', ref: 'Child' }]
+    });
+
+    const Node = db.model('Child', nodeSchema);
+    const Root = db.model('Parent', rootSchema);
+
+    const node = new Node({
+      _id: '65c7953e-c6e9-4c2f-8328-fe2de7df560d',
+      name: 'test'
+    });
+    await node.save();
+
+    const root = new Root({
+      _id: '05c7953e-c6e9-4c2f-8328-fe2de7df560d',
+      status: 'ok',
+      node: [node._id]
+    });
+    await root.save();
+
+    const foundRoot = await Root.findById(root._id).populate('node');
+
+    let doc = foundRoot.toJSON({ getters: true });
+    assert.strictEqual(doc._id, '05c7953e-c6e9-4c2f-8328-fe2de7df560d');
+    assert.strictEqual(doc.node.length, 1);
+    assert.strictEqual(doc.node[0]._id, '65c7953e-c6e9-4c2f-8328-fe2de7df560d');
+
+    doc = foundRoot.toObject({ getters: true });
+    assert.strictEqual(doc._id, '05c7953e-c6e9-4c2f-8328-fe2de7df560d');
+    assert.strictEqual(doc.node.length, 1);
+    assert.strictEqual(doc.node[0]._id, '65c7953e-c6e9-4c2f-8328-fe2de7df560d');
+  });
 });