Avoid useless transaction

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/store/db/CryptoStoreAggregator.kt

@@ -19,4 +19,9 @@ package org.matrix.android.sdk.internal.crypto.store.db
 data class CryptoStoreAggregator(
         val setShouldShareHistoryData: MutableMap<String, Boolean> = mutableMapOf(),
         val setShouldEncryptForInvitedMembersData: MutableMap<String, Boolean> = mutableMapOf(),
-)
+) {
+    fun isEmpty(): Boolean {
+        return setShouldShareHistoryData.isEmpty() &&
+                setShouldEncryptForInvitedMembersData.isEmpty()
+    }
+}

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/store/db/RealmCryptoStore.kt

@@ -1824,7 +1824,11 @@ internal class RealmCryptoStore @Inject constructor(
         val aggregator = cryptoStoreAggregator ?: return Unit.also {
             Timber.e("cryptoStoreAggregator is null...")
         }
+        cryptoStoreAggregator = null
 
+        if (aggregator.isEmpty()) {
+            return
+        }
         doRealmTransaction("onSyncCompleted", realmConfiguration) { realm ->
             // setShouldShareHistory
             aggregator.setShouldShareHistoryData.map {
@@ -1835,6 +1839,5 @@ internal class RealmCryptoStore @Inject constructor(
                 CryptoRoomEntity.getOrCreate(realm, it.key).shouldEncryptForInvitedMembers = it.value
             }
         }
-        cryptoStoreAggregator = null
     }
 }