From bcccab1669876abce2560457602321775e6903e1 Mon Sep 17 00:00:00 2001
From: Baraka Andrew <wizzleandre@gmail.com>
Date: Fri, 17 Dec 2021 14:46:06 +0900
Subject: [PATCH] panic when accessing map elements before initializing

---
 concurrent_map.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/concurrent_map.go b/concurrent_map.go
index 60386a2..7e7f1e4 100644
--- a/concurrent_map.go
+++ b/concurrent_map.go
@@ -198,6 +198,10 @@ func (m ConcurrentMap) Clear() {
 // It returns once the size of each buffered channel is determined,
 // before all the channels are populated using goroutines.
 func snapshot(m ConcurrentMap) (chans []chan Tuple) {
+	//When you access map items before initializing.
+	if len(m) == 0{
+		panic(`cmap.ConcurrentMap is not initialized. Should run New() before usage.`)
+	}
 	chans = make([]chan Tuple, SHARD_COUNT)
 	wg := sync.WaitGroup{}
 	wg.Add(SHARD_COUNT)