Catch broadcast receiver unregistration exception on Android

Reproducing the issue reliably has proven to be near impossible,
but the stack trace can be seen every now and then, and it does
not seem to cause any functional harm.

The strong suspicion on what happens is that in some places of the
code we create a temporary QBluetoothLocalDevice object to check
for example address(). This happens for example when creating a
QLowEnergyController object, which is one of the scenarios I recall
seeing the unhandled exception.

The localdevice creation triggers broadcast receiver registration,
and the ~immediate destruction triggers unregistration. Reading the
address() works as it does not rely on any broadcast events.

It seems plausible that in some cases the registration is not yet
fully complete on Android side when the unregistration is ~immediately
called.

Fixes: QTBUG-106938
Change-Id: Iac734f17fb9d2a1879fca39d9b2839cb530e5df5
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
(cherry picked from commit 29e73453ed653782fd885e79974de76bd60fc734)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/android/bluetooth/src/org/qtproject/qt/android/bluetooth/QtBluetoothBroadcastReceiver.java b/src/android/bluetooth/src/org/qtproject/qt/android/bluetooth/QtBluetoothBroadcastReceiver.java
index 7b163efb..6c74c3e3 100644
--- a/src/android/bluetooth/src/org/qtproject/qt/android/bluetooth/QtBluetoothBroadcastReceiver.java
+++ b/src/android/bluetooth/src/org/qtproject/qt/android/bluetooth/QtBluetoothBroadcastReceiver.java
@@ -51,7 +51,11 @@ public class QtBluetoothBroadcastReceiver extends BroadcastReceiver
     {
         synchronized (qtContext) {
             qtObject = 0;
-            qtContext.unregisterReceiver(this);
+            try {
+                qtContext.unregisterReceiver(this);
+            } catch (Exception ex) {
+                Log.d(TAG, "Trying to unregister a BroadcastReceiver which is not yet registered");
+            }
         }
     }