java.lang.AssertionError: hardAssert failed: listen() called twice for same QuerySpec.

[Kevinnad]

java.lang.AssertionError: hardAssert failed: listen() called twice for same QuerySpec.

[google-oss-bot]

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[lehcar09]

Hi @Kevinnad, thank you for reaching out. I tried reproducing the issue using our quickstart, however, I wasn't able to encounter the exception.

Here's how I implement it:

        databaseRef = Firebase.database
        val myRef = databaseRef.getReference("Devices")
        val isDeviceConnectedRef = myRef.child("myDevice").child("id")
        isDeviceConnectedRef.addValueEventListener(object : ValueEventListener {
            override fun onDataChange(dataSnapshot: DataSnapshot) {
                val newValue = dataSnapshot.getValue(String::class.java) ?: ""
                Log.d(TAG, "Value is: $newValue")
            }
            override fun onCancelled(error: DatabaseError) {
                // Failed to read value
                Log.w(TAG, "Failed to read value.", error.toException())
            }
        })

Did I misunderstood anything?

Can you share an MCVE or code snippet to help us investigate the issue? If you're unable to provide one, can you try our quickstart app and see if you can reproduce the issue?

Aside from that, are you constantly experiencing this error? or does the issue occur on certain devices and/or android versions?

[google-oss-bot]

Hey @Kevinnad. We need more information to resolve this issue but there hasn't been an update in 5 weekdays. I'm marking the issue as stale and if there are no new updates in the next 5 days I will close it automatically.

If you have more information that will help us get to the bottom of this, just add a comment!

[Kevinnad]

Hi @lehcar09 thanks for taking this issue

You first need to try with get, then same query with ValueEventListener, also try for multiple parallel request like the below snippet.

 val itemList = ArrayList<Object>()
        GlobalScope.launch {
            snapshots.map { snapshot ->
                return@map async(Dispatchers.Main) {
                        val dataSnapshot = databaseReferenceA().child(snapshot.key).get().await()
                        val result = dataSnapshot.getValue(Object::class.java)
                        return@async
                    } else {
                        return@async
                    }
                }
            }.awaitAll()

After the above code executed, call the below one of same DB reference

snapshots.map { snapshot ->
                        databaseReferenceA().child(snapshot.key).addValueEventListener(object : ValueEventListener {
            override fun onDataChange(dataSnapshot: DataSnapshot) {
                val newValue = dataSnapshot.getValue(String::class.java) ?: ""
                Log.d(TAG, "Value is: $newValue")
            }
            override fun onCancelled(error: DatabaseError) {
                // Failed to read value
                Log.w(TAG, "Failed to read value.", error.toException())
            }
        })
    }

[lehcar09]

I tried the code snippet you shared, however, I still wasn’t able to experience the issue. So far, it looks to me that there’s no issue on the SDK side.

I’m thinking if it’s possible that there are overlapping parallel calls happening at the same time that might be causing unwanted race conditions. Could you share an MCVE to further investigate the issue?

[google-oss-bot]

Hey @Kevinnad. We need more information to resolve this issue but there hasn't been an update in 5 weekdays. I'm marking the issue as stale and if there are no new updates in the next 5 days I will close it automatically.

If you have more information that will help us get to the bottom of this, just add a comment!