Fix stale consistent read result after server restart

src/ra_server.erl

@@ -1483,7 +1483,8 @@ machine_query(QueryFun, #{cfg := #cfg{effective_machine_module = MacMod},
 
 become(leader, #{cluster := Cluster, log := Log0} = State) ->
     Log = ra_log:release_resources(maps:size(Cluster) + 2, random, Log0),
-    State#{log => Log};
+    State#{log => Log,
+           cluster_change_permitted => false};
 become(follower, #{log := Log0} = State) ->
     %% followers should only ever need a single segment open at any one
     %% time

test/ra_SUITE.erl

@@ -45,6 +45,7 @@ all_tests() ->
      local_query_stale,
      members,
      consistent_query,
+     consistent_query_after_restart,
      consistent_query_minority,
      consistent_query_leader_change,
      consistent_query_stale,
@@ -544,6 +545,27 @@ consistent_query(Config) ->
     {ok, 14, Leader} = ra:consistent_query(A, fun(S) -> S end),
     terminate_cluster(Cluster).
 
+new_value(A, _) ->
+    A.
+
+consistent_query_after_restart(Config) ->
+    DataDir = filename:join([?config(priv_dir, Config), "data"]),
+    [A, B]  = Cluster = start_local_cluster(2, ?config(test_name, Config),
+                                            {simple, fun ?MODULE:new_value/2, 0}),
+    %% this test occasionally reproduces a stale read bug after a restart
+    %% NB: occasionally....
+    [begin
+         {ok, _, _} = ra:process_command(A, N, ?PROCESS_COMMAND_TIMEOUT),
+         application:stop(ra),
+         restart_ra(DataDir),
+         ok = ra:restart_server(A),
+         ok = ra:restart_server(B),
+         ?assertMatch({ok, N, _}, ra:consistent_query(A, fun(S) -> S end))
+     end || N <- lists:seq(1, 30)],
+
+    terminate_cluster(Cluster),
+    ok.
+
 consistent_query_minority(Config) ->
     [A, _, _]  = Cluster = start_local_cluster(3, ?config(test_name, Config),
                                                add_machine()),

test/ra_log_segment_writer_SUITE.erl

@@ -5,6 +5,7 @@
 %% Copyright (c) 2017-2022 VMware, Inc. or its affiliates.  All rights reserved.
 %%
 -module(ra_log_segment_writer_SUITE).
+-compile(nowarn_export_all).
 -compile(export_all).
 
 -include_lib("common_test/include/ct.hrl").