Fix a bug in Dets concerning repair of almost full tables

A Dets table with sufficiently large buckets could not always be repaired.
(Reported by Gordon Guthrie.)

The format of Dets files has been modified. When downgrading tables
created with the new system will be repaired. Otherwise the
modification should not be noticeable.

1 files changed, 90 insertions, 3 deletions

diff --git a/lib/stdlib/test/dets_SUITE.erl b/lib/stdlib/test/dets_SUITE.erl
index b68d83b12d..63767aeda6 100644
--- a/lib/stdlib/test/dets_SUITE.erl
+++ b/lib/stdlib/test/dets_SUITE.erl
@@ -34,6 +34,8 @@
 -define(datadir(Conf), ?config(data_dir, Conf)).
 -endif.
 
+-compile(r13). % OTP-9607
+
 -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1, 
 	 init_per_group/2,end_per_group/2, 
 	 not_run/1, newly_started/1, basic_v8/1, basic_v9/1,
@@ -53,7 +55,7 @@
          simultaneous_open/1, insert_new/1, repair_continuation/1,
          otp_5487/1, otp_6206/1, otp_6359/1, otp_4738/1, otp_7146/1,
          otp_8070/1, otp_8856/1, otp_8898/1, otp_8899/1, otp_8903/1,
-         otp_8923/1, otp_9282/1]).
+         otp_8923/1, otp_9282/1, otp_9607/1]).
 
 -export([dets_dirty_loop/0]).
 
@@ -112,7 +114,7 @@ all() ->
 	     many_clients, otp_4906, otp_5402, simultaneous_open,
 	     insert_new, repair_continuation, otp_5487, otp_6206,
 	     otp_6359, otp_4738, otp_7146, otp_8070, otp_8856, otp_8898,
-	     otp_8899, otp_8903, otp_8923, otp_9282]
+	     otp_8899, otp_8903, otp_8923, otp_9282, otp_9607]
     end.
 
 groups() -> 
@@ -554,7 +556,11 @@ dets_dirty_loop() ->
 	{From, [write, Name, Value]} ->
 	    Ret = dets:insert(Name, Value),
 	    From ! {self(), Ret},
-	    dets_dirty_loop()
+	    dets_dirty_loop();
+        {From, [close, Name]} ->
+            Ret = dets:close(Name),
+            From ! {self(), Ret},
+            dets_dirty_loop()
     end.
 
 
@@ -3882,10 +3888,91 @@ some_calls(Tab, Config) ->
     ?line ok = dets:close(T),
     file:delete(File).
 
+otp_9607(doc) ->
+    ["OTP-9607. Test downgrading the slightly changed format."];
+otp_9607(suite) ->
+    [];
+otp_9607(Config) when is_list(Config) ->
+    %% Note: the bug is about almost full tables. The fix of that
+    %% problem is *not* tested here.
+    Version = r13b,
+    case ?t:is_release_available(atom_to_list(Version)) of
+        true ->
+            T = otp_9607,
+            File = filename(T, Config),
+            Key = a,
+            Value = 1,
+            Args = [{file,File}],
+            ?line {ok, T} = dets:open_file(T, Args),
+            ?line ok = dets:insert(T, {Key, Value}),
+            ?line ok = dets:close(T),
+
+            ?line Call = fun(P, A) ->
+                                 P ! {self(), A},
+                                 receive
+                                     {P, Ans} ->
+                                         Ans
+                                 after 5000 ->
+                                         exit(other_process_dead)
+                                 end
+                         end,
+            %% Create a file on the modified format, read the file
+            %% with an emulator that doesn't know about the modified
+            %% format.
+            ?line {ok, Node} = start_node_rel(Version, Version, slave),
+            ?line Pid = rpc:call(Node, erlang, spawn,
+                                 [?MODULE, dets_dirty_loop, []]),
+            ?line {error,{needs_repair, File}} =
+                Call(Pid, [open, T, Args++[{repair,false}]]),
+            io:format("Expect repair:~n"),
+            ?line {ok, T} = Call(Pid, [open, T, Args]),
+            ?line [{Key,Value}] = Call(Pid, [read, T, Key]),
+            ?line ok = Call(Pid, [close, T]),
+            file:delete(File),
+
+            %% Create a file on the unmodified format. Modify the file
+            %% using an emulator that must not turn the file into the
+            %% modified format. Read the file and make sure it is not
+            %% repaired.
+            ?line {ok, T} = Call(Pid, [open, T, Args]),
+            ?line ok = Call(Pid, [write, T, {Key,Value}]),
+            ?line [{Key,Value}] = Call(Pid, [read, T, Key]),
+            ?line ok = Call(Pid, [close, T]),
+
+            Key2 = b,
+            Value2 = 2,
+
+            ?line {ok, T} = dets:open_file(T, Args),
+            ?line [{Key,Value}] = dets:lookup(T, Key),
+            ?line ok = dets:insert(T, {Key2,Value2}),
+            ?line ok = dets:close(T),
+
+            ?line {ok, T} = Call(Pid, [open, T, Args++[{repair,false}]]),
+            ?line [{Key2,Value2}] = Call(Pid, [read, T, Key2]),
+            ?line ok = Call(Pid, [close, T]),
+
+            ?t:stop_node(Node),
+            file:delete(File),
+            ok;
+        false ->
+	    {skipped, "No support for old node"}
+    end.
+
+
+
 %%
 %% Parts common to several test cases
 %% 
 
+start_node_rel(Name, Rel, How) ->
+    Release = [{release, atom_to_list(Rel)}],
+    ?line Pa = filename:dirname(code:which(?MODULE)),
+    ?line test_server:start_node(Name, How,
+                                 [{args,
+                                   " -kernel net_setuptime 100 "
+                                   " -pa " ++ Pa},
+                                  {erl, Release}]).
+
 crash(File, Where) ->
     crash(File, Where, 10).