Merge branch 'dotsimon/ref_ordering_bug/OTP-15225' into maint-21

* dotsimon/ref_ordering_bug/OTP-15225:
  Fixed #Ref ordering bug
  Test #Ref ordering in lists and ets

1 files changed, 27 insertions, 1 deletions

diff --git a/erts/emulator/test/ref_SUITE.erl b/erts/emulator/test/ref_SUITE.erl
index 5f519d522e..74df857c65 100644
--- a/erts/emulator/test/ref_SUITE.erl
+++ b/erts/emulator/test/ref_SUITE.erl
@@ -22,6 +22,7 @@
 
 -export([all/0, suite/0]).
 -export([wrap_1/1]).
+-export([compare_list/1, compare_ets/1]).
 
 -export([loop_ref/1]).
 
@@ -32,7 +33,7 @@ suite() ->
      {timetrap, {minutes, 2}}].
 
 all() -> 
-    [wrap_1].
+    [wrap_1, compare_list, compare_ets].
 
 %% Check that refs don't wrap around easily.
 wrap_1(Config) when is_list(Config) ->
@@ -53,3 +54,28 @@ loop_ref(Parent) ->
 loop_ref(R, R, _) -> ok;
 loop_ref(R0, _, N) ->
     loop_ref(R0, make_ref(), N+1).
+
+%% Check that ref ordering works
+compare_list(Config) when is_list(Config) ->
+    %% Although this test uses external refs, it would apply the same to plain refs
+    ExtRef1 = <<131,114,0,3,100,0,3,110,64,98,3, 0,0,173,156, 0,216,0,4, 0,0,0,0>>,
+    ExtRef2 = <<131,114,0,3,100,0,3,110,64,98,3, 0,1,31,27,   129,4,0,1, 0,0,0,0>>,
+
+    Ref1 = binary_to_term(ExtRef1), %% #Ref<[email protected]>
+    Ref2 = binary_to_term(ExtRef2), %% #Ref<[email protected]>
+    OrderedList = [Ref1, Ref2],
+    OrderedList = lists:sort(OrderedList),
+    ok.
+
+%% This is the scarier case since it makes terms "invisible" in ets or Mnesia
+%% (the underlying fault cause is the same as compare_list/1)
+compare_ets(Config) when is_list(Config) ->
+    W2s = [610350147,899574699,2994196869,686384822,2397690439, 923302211],
+    ExtRefBase = <<131,114,0,3,100,0,3,110,64,98,3>>,
+    ExtRefs = [<<ExtRefBase/binary, 1:32, W2:32, 0:32>> || W2 <- W2s],
+    Refs = [binary_to_term(Bin) || Bin <- ExtRefs],
+
+    Ets = ets:new(refbug, [ordered_set]),
+    ets:insert(Ets, [{Ref,Ref} || Ref <- Refs]),
+    0 = length([R || R <- ets:tab2list(Ets), ets:lookup(Ets, element(1,R)) == []]),
+    ok.