From 0cf8666ec6a8040e3eb2b9650e945cb234b31b1e Mon Sep 17 00:00:00 2001
From: Ziya Suzen <ziya@synadia.com>
Date: Fri, 22 Dec 2023 09:47:34 +0000
Subject: [PATCH] KV get keys should not hang with deleted keys (#293)

---
 src/NATS.Client.KeyValueStore/NatsKVStore.cs  |  5 +-
 .../GetKeysTest.cs                            | 48 +++++++++++++++++++
 2 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 tests/NATS.Client.KeyValueStore.Tests/GetKeysTest.cs

diff --git a/src/NATS.Client.KeyValueStore/NatsKVStore.cs b/src/NATS.Client.KeyValueStore/NatsKVStore.cs
index 45636b58a..0809ce258 100644
--- a/src/NATS.Client.KeyValueStore/NatsKVStore.cs
+++ b/src/NATS.Client.KeyValueStore/NatsKVStore.cs
@@ -415,7 +415,7 @@ public async IAsyncEnumerable<string> GetKeysAsync(NatsKVWatchOpts? opts = defau
 
         opts = opts with
         {
-            IgnoreDeletes = true,
+            IgnoreDeletes = false,
             MetaOnly = true,
             UpdatesOnly = false,
         };
@@ -427,7 +427,8 @@ public async IAsyncEnumerable<string> GetKeysAsync(NatsKVWatchOpts? opts = defau
         {
             while (watcher.Entries.TryRead(out var entry))
             {
-                yield return entry.Key;
+                if (entry.Operation is NatsKVOperation.Put)
+                    yield return entry.Key;
                 if (entry.Delta == 0)
                     yield break;
             }
diff --git a/tests/NATS.Client.KeyValueStore.Tests/GetKeysTest.cs b/tests/NATS.Client.KeyValueStore.Tests/GetKeysTest.cs
new file mode 100644
index 000000000..db4874f4e
--- /dev/null
+++ b/tests/NATS.Client.KeyValueStore.Tests/GetKeysTest.cs
@@ -0,0 +1,48 @@
+using NATS.Client.Core.Tests;
+
+namespace NATS.Client.KeyValueStore.Tests;
+
+public class GetKeysTest
+{
+    [Fact]
+    public async Task Get_keys_should_not_hang_when_there_are_deleted_keys()
+    {
+        const string bucket = "b1";
+        var config = new NatsKVConfig(bucket) { History = 10 };
+
+        var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+        var cancellationToken = cts.Token;
+
+        await using var server = NatsServer.StartJS();
+        await using var nats1 = server.CreateClientConnection();
+        var js1 = new NatsJSContext(nats1);
+        var kv1 = new NatsKVContext(js1);
+        var store1 = await kv1.CreateStoreAsync(config, cancellationToken: cancellationToken);
+
+        await store1.PutAsync("k1", 1, cancellationToken: cancellationToken);
+        await store1.PutAsync("k2", 2, cancellationToken: cancellationToken);
+        await store1.PutAsync("k3", 3, cancellationToken: cancellationToken);
+
+        var ks1 = new List<string>();
+        await foreach (var k in store1.GetKeysAsync(cancellationToken: cancellationToken))
+        {
+            ks1.Add(k);
+        }
+
+        ks1.Sort();
+
+        Assert.Equal(new List<string> { "k1", "k2", "k3" }, ks1);
+
+        await store1.DeleteAsync("k2", cancellationToken: cancellationToken);
+
+        var ks2 = new List<string>();
+        await foreach (var k in store1.GetKeysAsync(cancellationToken: cancellationToken))
+        {
+            ks2.Add(k);
+        }
+
+        ks2.Sort();
+
+        Assert.Equal(new List<string> { "k1", "k3" }, ks2);
+    }
+}