client: Change the initial sync to contain full state.

Fetching the full state with the initial sync is important because we
don't store any room state locally.

Since we don't store any sync token we are getting the full state
anyways. But once we do this change will be crucial for encryption to
work correctly.

pantalaimon/client.py

@@ -372,6 +372,15 @@ class PanClient(AsyncClient):
         logger.info(f"Starting sync loop for {self.user_id}")
 
         loop = asyncio.get_event_loop()
+
+        self.history_fetcher_task = loop.create_task(self.fetcher_loop())
+
+        task = loop.create_task(self.sync_loop())
+        self.task = task
+
+        return task
+
+    async def sync_loop(self):
         timeout = 30000
 
         sync_filter = {
@@ -380,11 +389,32 @@ class PanClient(AsyncClient):
             }
         }
 
-        task = loop.create_task(self.sync_forever(timeout, sync_filter))
-        self.task = task
-        self.history_fetcher_task = loop.create_task(self.fetcher_loop())
+        # We don't store any room state so initial sync needs to be with the
+        # full_state parameter. Subsequent ones are normal.
+        while True:
+            try:
+                response = await self.sync(
+                    sync_filter=sync_filter,
+                    full_state=True
+                )
+
+                if isinstance(response, SyncResponse):
+                    await self.sync_tasks(response)
+                    break
+                else:
+                    await asyncio.sleep(3)
+
+            except asyncio.CancelledError:
+                return
+
+            except ClientConnectionError:
+                try:
+                    await asyncio.sleep(3)
+                except asyncio.CancelledError:
+                    return
+
+        await self.sync_forever(timeout, sync_filter)
 
-        return task
 
     async def start_sas(self, message, device):
         try: