No slot map updates during a cluster client disconnect

Signed-off-by: Björn Svensson <[email protected]>

src/valkeycluster.c

@@ -3175,6 +3175,10 @@ static int updateSlotMapAsync(valkeyClusterAsyncContext *acc,
         /* Don't allow concurrent slot map updates. */
         return VALKEY_ERR;
     }
+    if (acc->cc->flags & VALKEYCLUSTER_FLAG_DISCONNECTING) {
+        /* No slot map updates during a cluster client disconnect. */
+        return VALKEY_ERR;
+    }
 
     if (ac == NULL) {
         if (acc->cc->nodes == NULL) {

tests/CMakeLists.txt

@@ -268,4 +268,8 @@ if (LIBEVENT_LIBRARY)
            COMMAND "${CMAKE_SOURCE_DIR}/tests/scripts/client-disconnect-test.sh"
                    "$<TARGET_FILE:clusterclient_async>"
            WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/tests/scripts/")
+  add_test(NAME client-disconnect-without-slotmap-update-test-async
+           COMMAND "${CMAKE_SOURCE_DIR}/tests/scripts/client-disconnect-without-slotmap-update-test.sh"
+                   "$<TARGET_FILE:clusterclient_async>"
+           WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/tests/scripts/")
 endif()

tests/scripts/client-disconnect-without-slotmap-update-test.sh

@@ -0,0 +1,104 @@
+#!/bin/bash
+#
+# Verify that a client disconnects from known nodes without starting new
+# slot map updates. A client shouldn't reconnect or connect to new nodes
+# while shutting down.
+#
+# This testcase starts 2 cluster nodes and the client connects to both.
+# The client triggers a disconnect right after a command has been sent,
+# which will invoke its callback with a NULL reply. This NULL reply
+# should not trigger a slot map update.
+#
+# Usage: $0 /path/to/clusterclient-binary
+
+clientprog=${1:-./clusterclient_async}
+testname=client-disconnect-without-slotmap-update-test
+
+# Sync process just waiting for server to be ready to accept connection.
+perl -we 'use sigtrap "handler", sub{exit}, "CONT"; sleep 1; die "timeout"' &
+syncpid1=$!
+perl -we 'use sigtrap "handler", sub{exit}, "CONT"; sleep 1; die "timeout"' &
+syncpid2=$!
+
+# Start simulated valkey node #1
+timeout 5s ./simulated-valkey.pl -p 7401 -d --sigcont $syncpid1 <<'EOF' &
+EXPECT CONNECT
+EXPECT ["CLUSTER", "SLOTS"]
+SEND [[0, 6000, ["127.0.0.1", 7401, "nodeid1"]],[6001, 16383, ["127.0.0.1", 7402, "nodeid2"]]]
+EXPECT CLOSE
+
+EXPECT CONNECT
+EXPECT ["SET", "bar", "initial"]
+SEND +OK
+
+# Normally a slot map update is expected here, but not during disconnects.
+
+EXPECT CLOSE
+EOF
+server1=$!
+
+# Start simulated valkey node #2
+timeout 5s ./simulated-valkey.pl -p 7402 -d --sigcont $syncpid2 <<'EOF' &
+EXPECT CONNECT
+EXPECT ["SET", "foo", "initial"]
+SEND +OK
+
+EXPECT ["SET", "foo", "null-reply"]
+# The client will invoke callbacks for outstanding requests with a NULL reply.
+# Normally this would trigger a slot map update, but not during disconnects.
+
+EXPECT CLOSE
+EOF
+server2=$!
+
+# Wait until both nodes are ready to accept client connections
+wait $syncpid1 $syncpid2;
+
+# Run client
+timeout 4s "$clientprog" --connection-events 127.0.0.1:7401 > "$testname.out" <<'EOF'
+SET foo initial
+SET bar initial
+
+# Make sure a slot map update is not throttled.
+!sleep
+
+# Send a command just before requesting a client disconnect.
+# A NULL reply should not trigger a slot map update after a disconnect.
+!async
+SET foo null-reply
+!disconnect
+!sync
+
+EOF
+clientexit=$?
+
+# Wait for servers to exit
+wait $server1; server1exit=$?
+wait $server2; server2exit=$?
+
+# Check exit statuses
+if [ $server1exit -ne 0 ]; then
+    echo "Simulated server #1 exited with status $server1exit"
+    exit $server1exit
+fi
+if [ $server2exit -ne 0 ]; then
+    echo "Simulated server #2 exited with status $server2exit"
+    exit $server2exit
+fi
+if [ $clientexit -ne 0 ]; then
+    echo "$clientprog exited with status $clientexit"
+    exit $clientexit
+fi
+
+expected="Event: connect to 127.0.0.1:7402
+OK
+Event: connect to 127.0.0.1:7401
+OK
+Event: disconnect from 127.0.0.1:7401
+error: Timeout
+Event: failed to disconnect from 127.0.0.1:7402"
+
+echo "$expected" | diff -u - "$testname.out" || exit 99
+
+# Clean up
+rm "$testname.out"