From b10f99ba3b9e5642cc4673cbaee834152bb6e883 Mon Sep 17 00:00:00 2001
From: Maurice van Veen <github@mauricevanveen.com>
Date: Sun, 9 Feb 2025 18:09:44 +0100
Subject: [PATCH] [FIXED] Preferred stream leader responds without initialized
 RAFT node

Signed-off-by: Maurice van Veen <github@mauricevanveen.com>
---
 server/jetstream_api.go            | 11 +++++-----
 server/jetstream_cluster_3_test.go | 34 ++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/server/jetstream_api.go b/server/jetstream_api.go
index 1b82aa4d60..4edc99bbd3 100644
--- a/server/jetstream_api.go
+++ b/server/jetstream_api.go
@@ -1873,13 +1873,14 @@ func (s *Server) jsStreamInfoRequest(sub *subscription, c *client, a *Account, s
 			if cc.meta != nil {
 				ourID = cc.meta.ID()
 			}
-			// We have seen cases where rg or rg.node is nil at this point,
-			// so check explicitly on those conditions and bail if that is
-			// the case.
-			bail := rg == nil || rg.node == nil || !rg.isMember(ourID)
+			// We have seen cases where rg is nil at this point,
+			// so check explicitly and bail if that is the case.
+			bail := rg == nil || !rg.isMember(ourID)
 			if !bail {
 				// We know we are a member here, if this group is new and we are preferred allow us to answer.
-				bail = rg.Preferred != ourID || time.Since(rg.node.Created()) > lostQuorumIntervalDefault
+				// Also, we have seen cases where rg.node is nil at this point,
+				// so check explicitly and bail if that is the case.
+				bail = rg.Preferred != ourID || (rg.node != nil && time.Since(rg.node.Created()) > lostQuorumIntervalDefault)
 			}
 			js.mu.RUnlock()
 			if bail {
diff --git a/server/jetstream_cluster_3_test.go b/server/jetstream_cluster_3_test.go
index d2aed87836..13ca180bb0 100644
--- a/server/jetstream_cluster_3_test.go
+++ b/server/jetstream_cluster_3_test.go
@@ -1319,6 +1319,40 @@ func TestJetStreamClusterNoPanicOnStreamInfoWhenNoLeaderYet(t *testing.T) {
 	wg.Wait()
 }
 
+func TestJetStreamClusterNoTimeoutOnStreamInfoOnPreferredLeader(t *testing.T) {
+	c := createJetStreamClusterExplicit(t, "R3S", 3)
+	defer c.shutdown()
+
+	nc, js := jsClientConnect(t, c.randomServer())
+	defer nc.Close()
+
+	_, err := js.AddStream(&nats.StreamConfig{
+		Name:     "TEST",
+		Subjects: []string{"foo"},
+		Replicas: 3,
+	})
+	require_NoError(t, err)
+
+	_, err = js.StreamInfo("TEST")
+	require_NoError(t, err)
+
+	// Simulate the preferred stream leader to not have initialized the raft node yet.
+	sl := c.streamLeader(globalAccountName, "TEST")
+	acc, err := sl.lookupAccount(globalAccountName)
+	require_NoError(t, err)
+	mset, err := acc.lookupStream("TEST")
+	require_NoError(t, err)
+	sjs := sl.getJetStream()
+	rg := mset.raftGroup()
+	sjs.mu.Lock()
+	rg.node = nil
+	sjs.mu.Unlock()
+
+	// Should not time out on the stream info during this condition.
+	_, err = js.StreamInfo("TEST")
+	require_NoError(t, err)
+}
+
 // Issue https://github.com/nats-io/nats-server/issues/3630
 func TestJetStreamClusterPullConsumerAcksExtendInactivityThreshold(t *testing.T) {
 	c := createJetStreamClusterExplicit(t, "R3S", 3)