Firestore document update is failing - firebase

Question

i have documents in firestore which i am trying to update. These updates are successful for old users but failing for new users. I have listview where user can see all the added documents. They click on Edit and then they are navigated to a detailed document view where they can make changes and save.
Error which i am receiving
[VERBOSE-2:ui_dart_state.cc(209)] Unhandled Exception:
[cloud_firestore/not-found] Some requested document was not found.
I am passing document id with following from list view to single document edit view;
data: docId
In the edit page, i am loading the user id and doc id which is coming from previous page.
class Edit extends StatefulWidget {
final DataModel data;
Edit({required this.data});
String ui = FirebaseAuth.instance.currentUser!.uid;
#override
_EditState createState() => _EditState();
}
On save button i am updating firestore with following;
ElevatedButton.styleFrom(primary: Colors.redAccent),
onPressed: () async {
DocumentReference edit = FirebaseFirestore
.instance
.collection('edit')
.doc(ui)
.collection('edit')
.doc(widget.data.documentId);
edit.update({
});

Answer 1

The cloud_firestore/not-found error means the document was not found under the specified id. Please make sure the id really exists in your database.
If you are using the local emulator, make sure you are accessing the correct database.
If you are using persistent storage (offline firestore data) it might be that it still has old data or your device didn't connect to the internet and thus doesn't have the current data.

Answer 2

The error message is telling you that the document you build a reference to was not found for update.
There are a few ways to update data to Cloud Firestore:
update - change fields on a document that already exists.
Fails if the document does not exist.
set - overwrite the data in a document, creating the
document if it does not already exist. If you want to only partially
update a document, use SetOptions.merge(). If you want to be able to
create a document if it doesn't exist, or update it if it does
already exist, you should pass SetOptions.merge as the second
parameter, as explained by the API documentation.
So you just need to use the correct operation for your use case.
If you want to update a document without knowing if it exists or not,
you want to use a set() with the merge() option like this (this
example is for Java):
// Update one field, creating the document if it does not already exist.
Map<String, Object> data = new HashMap<>();
data.put("capital", true);
db.collection("cities").document("BJ") .set(data, SetOptions.merge());
Also one classical problem when using auth.currentUser is that it is
possible that the Auth object is not fully initialized and that
auth.currentUser.uid is therefore null. As explained in the doc you
should either use the onAuthStateChanged() observer or check that
auth.currentUser is not null.
Try :
ElevatedButton.styleFrom(primary: Colors.redAccent),
onPressed: ()
async {
DocumentReference edit = FirebaseFirestore .instance .collection('edit') .doc(FirebaseAuth.instance.currentUser.uid) .collection('edit') .doc(widget.data.documentId);
edit.update({ });