CODEWITHSUNDEEP
androidfirebasekotlingoogle-cloud-platformgoogle-cloud-firestore
kaushalyap
kaushalyap

Reputation: 13607

Non of the Firestore task handlers are being called if there is no matching document for query

I'm following a simple code that checks if a document exists containing a specified email address. But if the email does not exist and no matching documents neither addOnCompleteListener or addOnSuccessListner or addOnFailureListener are not getting called.

val db = Firebase.firestore

db.collection("Users").whereEqualTo("email", "[email protected]").get()
        .addOnSuccessListener {  QuerySnapshot ->
            Log.d(TAG, "${QuerySnapshot.documents.size}")
        }
        .addOnCanceledListener {
            Log.d(TAG, "Request was canceled!")
        }
        .addOnFailureListener { exception ->
            Log.d(TAG, "$exception")
        }
        .addOnCompleteListener { task ->
            if (task.isSuccessful) {
                for (document in task.result) {
                    Log.d(TAG, "${document.id}")
                }
            } else {
                Log.d(TAG, "Error getting documents: ", task.exception)
            }
        }

As I understand this is not the expected behavior. Am I missing something here?

I am using the following as dependencies:

implementation platform('com.google.firebase:firebase-bom:29.0.0')
implementation 'com.google.firebase:firebase-firestore-ktx'

Update:

I tried bom:29.1.0 still the same behavior, I do have internet, mutations like add() works fine

Upvotes: 1

Views: 109

Answers (1)

Alex Mamo
Alex Mamo

Reputation: 138824

When your query yields no results, addOnFailureListener won't be triggered, since the absence of some documents won't be considered an Exception. However, if your query will be rejected due to improper security rules, then an Exception will be thrown for sure.

You say that addOnCompleteListener is also not triggered when your query doesn't return any documents. But I doubt it since you say that add() works fine, meaning that you have an internet connection on the user device. Most likely it's triggered but you don't know it. Why? Because you aren't handling that case.

If you get no results, addOnCompleteListener indeed fires, meaning that task.isSuccessful returns true. This also means that the else part won't be evaluated. Since there are no documents, the for-each loop won't print anything. The best option that you have is to check the documents for existence:

.addOnCompleteListener { task ->
    if (task.isSuccessful) {
        for (document in task.result) {
            if(document.exists()) {
                Log.d(TAG, "${document.id}")
            } else {
                Log.d(TAG, "Document doesn't exist.")
            }
        }
    } else {
        Log.d(TAG, "Error getting documents: ", task.exception)
    }
}

Upvotes: 3

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