[Flutter/dart] 'isDocument()': is not true.

Phenomenon

I get the following error when trying to save data to firestore.

Unhandled Exception: 'package:cloud_firestore_platform_interface/src/internal/pointer.dart': Failed assertion: line 53 pos 12: 'isDocument()': is not true.

Cause and Solution

There was a "/" in the id of the firestore document.

I wanted the id of the document to be a date, so I set an id like "2021/01/02".

However, firestore remembers the path with the delimiter of document and collection as /, and determines whether the path specified as the data save destination is document or collection only by the even number or odd number from the beginning with / as the delimiter.

Therefore, if the id contains /, the path was not set correctly.

The only solution is to avoid using / for id.

In my case, I solved it by changing the id to "2021-01-02".