Don't remind to sync if the lock is claimed (#833)

If the sync lock is claimed in Team Create, the user cannot sync.
Therefore, a sync reminder notification is unhelpful as it is calling to
an invalid action.

plugin/src/App/init.lua

@@ -136,6 +136,7 @@ function App:init()
 		and self.serveSession == nil
 		and Settings:get("syncReminder")
 		and self:getLastSyncTimestamp()
+		and (self:isSyncLockAvailable())
 	then
 		self:addNotification("You've previously synced this place. Would you like to reconnect?", 300, {
 			Connect = {
@@ -283,12 +284,39 @@ function App:getHostAndPort()
 	return host, port
 end
 
+function App:isSyncLockAvailable()
+	if #Players:GetPlayers() == 0 then
+		-- Team Create is not active, so no one can be holding the lock
+		return true
+	end
+
+	local lock = ServerStorage:FindFirstChild("__Rojo_SessionLock")
+	if not lock then
+		-- No lock is made yet, so it is available
+		return true
+	end
+
+	if lock.Value and lock.Value ~= Players.LocalPlayer and lock.Value.Parent then
+		-- Someone else is holding the lock
+		return false, lock.Value
+	end
+
+	-- The lock exists, but is not claimed
+	return true
+end
+
 function App:claimSyncLock()
 	if #Players:GetPlayers() == 0 then
 		Log.trace("Skipping sync lock because this isn't in Team Create")
 		return true
 	end
 
+	local isAvailable, priorOwner = self:isSyncLockAvailable()
+	if not isAvailable then
+		Log.trace("Skipping sync lock because it is already claimed")
+		return false, priorOwner
+	end
+
 	local lock = ServerStorage:FindFirstChild("__Rojo_SessionLock")
 	if not lock then
 		lock = Instance.new("ObjectValue")
@@ -300,11 +328,6 @@ function App:claimSyncLock()
 		return true
 	end
 
-	if lock.Value and lock.Value ~= Players.LocalPlayer and lock.Value.Parent then
-		Log.trace("Found existing sync lock owned by {}", lock.Value)
-		return false, lock.Value
-	end
-
 	lock.Value = Players.LocalPlayer
 	Log.trace("Claimed existing sync lock")
 	return true