Firestore set with merge true, will remove empty inner objects

[mohshraim]

[REQUIRED] Describe your environment

• Operating System version: macOS Hight Sierra
• Browser version: chrome Version 67.0.3396.99
• Firebase SDK version: 5.4.1
• Firebase Product: firestore

[REQUIRED] Describe the problem

Steps to reproduce:

when update document with set function and merge option true, i will lose the inner empty objects.

Relevant Code:

var doc = { obj1: { key1: true } , obj2: {} };

firestore.collection('item').doc('item-1').set(doc);
//without merge option
// the stored doc on firestore server will be  { obj1: { key1: true } , obj2: {}  }   => this correct
//******************************
firestore.collection('item').doc('item-1').set(doc, { merge: true });
//with merge option
// the stored doc on firestore server will be  { obj1: { key1: true }  }   => this missing the obj2

Is this normal behavior?
Thanks

[schmidt-sebastian]

@mohshraim Thanks for flagging this. We should definitely not drop the empty object. We will get back to you when we have a fix.

[mohshraim]

Thanks for confirmation.