From b4f4e936b25f04cc0d71e997fac8ce7b78dffd5f Mon Sep 17 00:00:00 2001
From: Karl Nilsson <kjnilsson@gmail.com>
Date: Thu, 11 Jul 2024 11:12:37 +0100
Subject: [PATCH] Ensure cluster_index_term is updated after snapshot
 installation.

If the snapshot contained a member change it may not update
the leaderboard correctly.
---
 src/ra_server.erl         | 3 +++
 src/ra_server_sup_sup.erl | 1 +
 test/ra_2_SUITE.erl       | 4 ++++
 test/ra_server_SUITE.erl  | 1 +
 4 files changed, 9 insertions(+)

diff --git a/src/ra_server.erl b/src/ra_server.erl
index be4d0893..b301d1da 100644
--- a/src/ra_server.erl
+++ b/src/ra_server.erl
@@ -1384,6 +1384,9 @@ handle_receive_snapshot(#install_snapshot_rpc{term = Term,
                                         log => Log,
                                         commit_index => SnapIndex,
                                         last_applied => SnapIndex,
+                                        %% this may not be the actual cluster index
+                                        cluster_index_term => {SnapIndex,
+                                                               SnapTerm},
                                         cluster => make_cluster(Id, ClusterIds),
                                         membership => get_membership(ClusterIds, State0),
                                         machine_state => MacState}),
diff --git a/src/ra_server_sup_sup.erl b/src/ra_server_sup_sup.erl
index c96f152e..855af650 100644
--- a/src/ra_server_sup_sup.erl
+++ b/src/ra_server_sup_sup.erl
@@ -166,6 +166,7 @@ delete_server_rpc(System, RaName) ->
             catch ets:delete(ra_state, RaName),
             catch ets:delete(ra_open_file_metrics, Pid),
             catch ra_counters:delete({RaName, node()}),
+            catch ra_leaderboard:clear(RaName),
             ok
     end.
 
diff --git a/test/ra_2_SUITE.erl b/test/ra_2_SUITE.erl
index 8468ca41..8dc869e0 100644
--- a/test/ra_2_SUITE.erl
+++ b/test/ra_2_SUITE.erl
@@ -157,9 +157,13 @@ server_is_force_deleted(Config) ->
     % force roll over
     ok = force_roll_over(),
     Pid = ra_directory:where_is(?SYS, UId),
+    {Name, _} = ServerId,
+    ?assertEqual(ServerId, ra_leaderboard:lookup_leader(Name)),
     ok = ra:force_delete_server(?SYS, ServerId),
 
     validate_ets_table_deletes([UId], [Pid], [ServerId]),
+    ?assertEqual(undefined, ra_leaderboard:lookup_leader(Name)),
+    ct:pal("ra_leaderboard overview ~p", [ra_leaderboard:overview()]),
     % start a node with the same nodeid but different uid
     % simulating the case where a queue got deleted then re-declared shortly
     % afterwards
diff --git a/test/ra_server_SUITE.erl b/test/ra_server_SUITE.erl
index 89113683..321e45ce 100644
--- a/test/ra_server_SUITE.erl
+++ b/test/ra_server_SUITE.erl
@@ -1489,6 +1489,7 @@ follower_install_snapshot_machine_version(_Config) ->
                              effective_machine_module = MacMod1,
                              effective_machine_version = 1},
                  last_applied := 4,
+                 cluster_index_term := {4, 5},
                  machine_state := SnapData, %% old machine state
                  commit_index := 4},
      _} = ra_server:handle_receive_snapshot(ISR, State0),