Firebase deleted data still there - firebase

Question

i have a behavior that I can't understand.
I delete a node on firebase database and I still receive the data during observing .value. But in firebase database the node is deleted.
I have a node called users_shoppinglists. Here are all id's of the users nodes to observe stored. Then I iterate all the id's to observe and call a function that observes each ID.
When I need to delete a list I update a node called status on the shoppinglists node and delete all to this list related data via cloud functions.
But the data is still received during observe. It seems I receive the data again before it is completely deleted.
Iterate all id's:
func ObserveAllList() -> Void{
if currentUser == nil { return }
self.ShowActivityIndicator()
ref.child("users_shoppinglists").child(currentUser!.id!).observe(.value, with: { (usersListsSnap) in
if usersListsSnap.value is NSNull { self.HideActivityIndicator(); return }
for listSnap in usersListsSnap.children {
let list = listSnap as! DataSnapshot
self.ObserveSingleList(listID: list.key)
}
}) { (error) in
NSLog(error.localizedDescription)
let title = String.OnlineFetchRequestError
let message = error.localizedDescription
self.ShowAlertMessage(title: title, message: message)
return
}
}
Call function to observe each ID:
func ObserveSingleList(listID:String) -> Void {
self.ShowActivityIndicator()
ref.child("shoppinglists").child(listID).observeSingleEvent(of: .value, with: { (snapshot) in
if snapshot.value is NSNull { self.HideActivityIndicator(); return }
//Read listData
var newList = ShoppingList()
newList.id = snapshot.key
newList.name = snapshot.childSnapshot(forPath: "listName").value as? String
newList.owneruid = snapshot.childSnapshot(forPath: "owneruid").value as? String
newList.relatedStore = snapshot.childSnapshot(forPath: "relatedStore").value as? String
//Read List items
self.ref.child("listItems").child(listID).observe(.value, with: { (itemSnap) in
var newItems = [ShoppingListItem]()
for items in itemSnap.children {
let item = items as! DataSnapshot
var newItem = ShoppingListItem()
newItem.id = item.key
newItem.listID = listID
newItem.isSelected = item.childSnapshot(forPath: "isSelected").value as? Bool
newItem.itemName = item.childSnapshot(forPath: "itemName").value as? String
newItem.sortNumber = item.childSnapshot(forPath: "sortNumber").value as? Int
newItems.append(newItem)
}
newList.items = newItems
//Read List members
self.ref.child("shoppinglist_member").child(listID).observe(.value, with: { (memberSnap) in
var newMembers = [ShoppingListMember]()
for members in memberSnap.children {
let member = members as! DataSnapshot
var m = ShoppingListMember()
m.memberID = member.key
m.status = member.value as? String
newMembers.append(m)
}
newList.members = newMembers
DispatchQueue.main.async {
if let index = allShoppingLists.index(where: { $0.id == listID }){
allShoppingLists[index] = newList
} else {
allShoppingLists.append(newList)
}
self.HideActivityIndicator()
NotificationCenter.default.post(name: Notification.Name.ShoppingBuddyListDataReceived, object: nil, userInfo: nil)
}
}, withCancel: { (error) in
self.HideActivityIndicator()
NSLog(error.localizedDescription)
let title = String.OnlineFetchRequestError
let message = error.localizedDescription
self.ShowAlertMessage(title: title, message: message)
return
})
}, withCancel: { (error) in
self.HideActivityIndicator()
NSLog(error.localizedDescription)
let title = String.OnlineFetchRequestError
let message = error.localizedDescription
self.ShowAlertMessage(title: title, message: message)
return
})
}) { (error) in
self.HideActivityIndicator()
NSLog(error.localizedDescription)
let title = String.OnlineFetchRequestError
let message = error.localizedDescription
self.ShowAlertMessage(title: title, message: message)
return
}
}
Cloud function:
//****************************************************************************************************************/
// Handles an action when status value changed in users_shoppinglists node
//****************************************************************************************************************/
exports.handle_ListStatusUpdate = functions.database.ref('/shoppinglists/{listID}').onUpdate(event => {
var listData = event.data.val()
console.log('Status', listData.status)
//handle deleted by owner
if (String(listData.status) == 'deleted by owner') {
//Get all members to delete the list on their users_shoppinglists node
return admin.database().ref('shoppinglist_member').child(event.params.listID).once('value').then(listMember => {
var promises = []
listMember.forEach(function (member) {
promises.push(admin.database().ref('users_shoppinglists').child(member.key).child(event.params.listID).set(null).then(() => {
return admin.database().ref('shoppinglist_member').child(event.params.listID).set(null).then(() => {
// delete the original shopping list
return admin.database().ref('shoppinglists').child(event.params.listID).set(null).then(() => {
return admin.database().ref('listItems').child(event.params.listID).set(null).then(() => {
})
})
})
}))
})
})
}
});/*********************************************************************************************************** */

Answer 1

Had this issue on Simulator. It was not only .value but .childRemoved and .childChanged were not triggered at all (only .childAdded was working).
Tried on iPhone and it worked. Then I made "Erase All Content And Settings..." to Simulator and it started to work again on Simulator too.
My bet is that firebase cache gets dirty during development, while you add or remove observers in code and probably change structure in database and at some point it just stops reacting appropriately.