Test that tries to reproduce a race condition

tests/queries/0_stateless/02242_delete_user_race.sh

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+# Tags: race, no-fasttest, no-parallel
+
+# Test tries to reproduce a race between threads:
+# - deletes user
+# - creates user
+# - uses it as session user
+# - apply role to the user
+#
+# https://github.com/ClickHouse/ClickHouse/issues/35714
+
+set -e
+
+CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CURDIR"/../shell_config.sh
+# shellcheck source=./replication.lib
+. "$CURDIR"/replication.lib
+
+#export PS4='\nDEBUG level:$SHLVL subshell-level: $BASH_SUBSHELL \nsource-file:${BASH_SOURCE} line#:${LINENO} function:${FUNCNAME[0]:+${FUNCNAME[0]}(): }\nstatement: '
+
+
+$CLICKHOUSE_CLIENT -nm -q "
+    DROP ROLE IF EXISTS test_role_02242;
+    CREATE ROLE test_role_02242;
+"
+
+readonly REPEAT=1000
+
+function delete_user()
+{
+    local i
+    for (( i = 0; i < REPEAT; ++i ))
+    do
+        $CLICKHOUSE_CLIENT -q "DROP USER IF EXISTS test_user_02242" ||:
+    done
+}
+
+function create_and_login_user()
+{
+    local i
+    for (( i = 0; i < REPEAT; ++i ))
+    do
+        $CLICKHOUSE_CLIENT -q "CREATE USER IF NOT EXISTS test_user_02242" ||:
+        $CLICKHOUSE_CLIENT -u "test_user_02242" -q "SELECT version()" > /dev/null ||:
+    done
+}
+
+function set_role()
+{
+    local i
+    for (( i = 0; i < REPEAT; ++i ))
+    do
+        $CLICKHOUSE_CLIENT -q "SET ROLE test_role_02242 TO test_user_02242" ||:
+    done
+}
+
+export -f delete_user
+export -f create_and_login_user
+export -f set_role
+
+
+TIMEOUT=0.1
+
+for (( i = 0 ; i < 1000; ++i ))
+do
+    clickhouse_client_loop_timeout $TIMEOUT create_and_login_user 2> /dev/null &
+    clickhouse_client_loop_timeout $TIMEOUT delete_user 2> /dev/null &
+    clickhouse_client_loop_timeout $TIMEOUT login_user 2> /dev/null &
+    clickhouse_client_loop_timeout $TIMEOUT set_role 2> /dev/null &
+done
+
+wait
+
+# $CLICKHOUSE_CLIENT -q "DROP ROLE IF EXISTS test_role_02242"
+# $CLICKHOUSE_CLIENT -q "DROP USER IF EXISTS test_user_02242"
+
+# wait