Remove BCC from x-death routing-keys

This commit is a follow up of #11174
which broke the following Java client test:
```
./mvnw verify -P '!setup-test-cluster' -Drabbitmqctl.bin=DOCKER:rabbitmq -Dit.test=DeadLetterExchange#deadLetterNewRK
```

The desired documented behaviour is the following:
> routing-keys: the routing keys (including CC keys but excluding BCC ones) the message was published with

This behaviour should be respected also for messages dead lettered into a
stream. Therefore, instead of first including the BCC keys in the `#death.routing_keys` field
and removing it again in mc_amqpl before sending the routing-keys to the
client as done in v3.13.2 in
https://github.com/rabbitmq/rabbitmq-server/blob/dc25ef53292eb0b34588ab8eaae61082b966b784/deps/rabbit/src/mc_amqpl.erl#L527
we instead omit directly the BCC keys from `#death.routing_keys` when
recording a death event.

This commit records the BCC keys in their own mc `bcc` annotation in `mc_amqpl:init/1`.

deps/rabbit/src/mc.erl

@@ -365,14 +365,22 @@ record_death(Reason, SourceQueue,
        is_binary(SourceQueue) ->
     Key = {SourceQueue, Reason},
     #{?ANN_EXCHANGE := Exchange,
-      ?ANN_ROUTING_KEYS := RoutingKeys} = Anns0,
+      ?ANN_ROUTING_KEYS := RKeys0} = Anns0,
+    %% The routing keys that we record in the death history and will
+    %% report to the client should include CC, but exclude BCC.
+    RKeys = case Anns0 of
+                #{bcc := BccKeys} ->
+                    RKeys0 -- BccKeys;
+                _ ->
+                    RKeys0
+            end,
     Timestamp = os:system_time(millisecond),
     Ttl = maps:get(ttl, Anns0, undefined),
     DeathAnns = rabbit_misc:maps_put_truthy(
                   ttl, Ttl, #{first_time => Timestamp,
                               last_time => Timestamp}),
     NewDeath = #death{exchange = Exchange,
-                      routing_keys = RoutingKeys,
+                      routing_keys = RKeys,
                       count = 1,
                       anns = DeathAnns},
     Anns = case Anns0 of

deps/rabbit/src/mc_amqpl.erl

@@ -51,10 +51,11 @@
 
 %% mc implementation
 init(#content{} = Content0) ->
-    Content = rabbit_binary_parser:ensure_content_decoded(Content0),
+    Content1 = rabbit_binary_parser:ensure_content_decoded(Content0),
     %% project essential properties into annotations
-    Anns = essential_properties(Content),
-    {strip_header(Content, ?DELETED_HEADER), Anns}.
+    Anns = essential_properties(Content1),
+    Content = strip_header(Content1, ?DELETED_HEADER),
+    {Content, Anns}.
 
 convert_from(mc_amqp, Sections, Env) ->
     {H, MAnn, Prop, AProp, BodyRev, Footer} =
@@ -554,7 +555,7 @@ message(#resource{name = ExchangeNameBin},
             Error;
         HeaderRoutes ->
             {ok, mc:init(?MODULE,
-                         rabbit_basic:strip_bcc_header(Content),
+                         Content,
                          Anns#{?ANN_ROUTING_KEYS => [RoutingKey | HeaderRoutes],
                                ?ANN_EXCHANGE => ExchangeNameBin})}
     end.
@@ -795,7 +796,8 @@ message_id(undefined, _HKey, H) ->
 essential_properties(#content{} = C) ->
     #'P_basic'{delivery_mode = Mode,
                priority = Priority,
-               timestamp = TimestampRaw} = Props = C#content.properties,
+               timestamp = TimestampRaw,
+               headers = Headers} = Props = C#content.properties,
     {ok, MsgTTL} = rabbit_basic:parse_expiration(Props),
     Timestamp = case TimestampRaw of
                     undefined ->
@@ -805,6 +807,12 @@ essential_properties(#content{} = C) ->
                         TimestampRaw * 1000
                 end,
     Durable = Mode == 2,
+    BccKeys = case rabbit_basic:header(<<"BCC">>, Headers) of
+                  {<<"BCC">>, array, Routes} ->
+                      [Route || {longstr, Route} <- Routes];
+                  _ ->
+                      undefined
+              end,
     maps_put_truthy(
       ?ANN_PRIORITY, Priority,
       maps_put_truthy(
@@ -813,7 +821,9 @@ essential_properties(#content{} = C) ->
           ?ANN_TIMESTAMP, Timestamp,
           maps_put_falsy(
             ?ANN_DURABLE, Durable,
-            #{})))).
+            maps_put_truthy(
+              bcc, BccKeys,
+              #{}))))).
 
 %% headers that are added as annotations during conversions
 is_internal_header(<<"x-basic-", _/binary>>) ->

deps/rabbit/test/dead_lettering_SUITE.erl

@@ -1379,17 +1379,18 @@ dead_letter_headers_BCC(Config) ->
                                                              routing_key = DLXQName}),
 
     P1 = <<"msg1">>,
-    BCCHeader = {<<"BCC">>, array, [{longstr, DLXQName}]},
-    publish(Ch, QName, [P1], [BCCHeader]),
+    CCHeader = {<<"CC">>, array, [{longstr, <<"cc 1">>}, {longstr, <<"cc 2">>}]},
+    BCCHeader = {<<"BCC">>, array, [{longstr, DLXQName}, {longstr, <<"bcc 2">>}]},
+    publish(Ch, QName, [P1], [CCHeader, BCCHeader]),
     %% Message is published to both queues because of BCC header and DLX queue bound to both
     %% exchanges
     wait_for_messages(Config, [[QName, <<"1">>, <<"1">>, <<"0">>]]),
     {#'basic.get_ok'{delivery_tag = DTag1}, #amqp_msg{payload = P1,
                                                       props = #'P_basic'{headers = Headers1}}} =
-        amqp_channel:call(Ch, #'basic.get'{queue = QName}),
+    amqp_channel:call(Ch, #'basic.get'{queue = QName}),
     {#'basic.get_ok'{}, #amqp_msg{payload = P1,
                                   props = #'P_basic'{headers = Headers2}}} =
-        amqp_channel:call(Ch, #'basic.get'{queue = DLXQName}),
+    amqp_channel:call(Ch, #'basic.get'{queue = DLXQName}),
     %% We check the headers to ensure no dead lettering has happened
     ?assertEqual(undefined, header_lookup(Headers1, <<"x-death">>)),
     ?assertEqual(undefined, header_lookup(Headers2, <<"x-death">>)),
@@ -1401,10 +1402,15 @@ dead_letter_headers_BCC(Config) ->
     wait_for_messages(Config, [[DLXQName, <<"2">>, <<"1">>, <<"1">>]]),
     {#'basic.get_ok'{}, #amqp_msg{payload = P1,
                                   props = #'P_basic'{headers = Headers3}}} =
-        amqp_channel:call(Ch, #'basic.get'{queue = DLXQName}),
+    amqp_channel:call(Ch, #'basic.get'{queue = DLXQName}),
     consume_empty(Ch, QName),
     ?assertEqual(undefined, rabbit_misc:table_lookup(Headers3, <<"BCC">>)),
-    ?assertMatch({array, _}, rabbit_misc:table_lookup(Headers3, <<"x-death">>)).
+    {array, [{table, Death}]} = rabbit_misc:table_lookup(Headers3, <<"x-death">>),
+    {array, RKeys0} = rabbit_misc:table_lookup(Death, <<"routing-keys">>),
+    RKeys = [RKey || {longstr, RKey} <- RKeys0],
+    %% routing-keys in the death history should include CC but exclude BCC keys
+    ?assertEqual(lists:sort([QName, <<"cc 1">>, <<"cc 2">>]),
+                 lists:sort(RKeys)).
 
 %% Three top-level headers are added for the very first dead-lettering event.
 %% They are
@@ -1669,7 +1675,11 @@ stream(Config) ->
       #'basic.publish'{routing_key = Q1},
       #amqp_msg{payload = Payload,
                 props = #'P_basic'{expiration = <<"0">>,
-                                   headers = [{<<"CC">>, array, [{longstr, <<"other key">>}]}]}
+                                   headers = [{<<"CC">>, array, [{longstr, <<"cc 1">>},
+                                                                 {longstr, <<"cc 2">>}]},
+                                              {<<"BCC">>, array, [{longstr, <<"bcc 1">>},
+                                                                  {longstr, <<"bcc 2">>}]}
+                                             ]}
                }),
 
     #'basic.qos_ok'{} = amqp_channel:call(Ch1, #'basic.qos'{prefetch_count = 1}),
@@ -1710,7 +1720,10 @@ stream(Config) ->
     ?assertEqual({longstr, Reason}, rabbit_misc:table_lookup(Death1, <<"reason">>)),
     ?assertEqual({longstr, <<>>}, rabbit_misc:table_lookup(Death1, <<"exchange">>)),
     ?assertEqual({long, 1}, rabbit_misc:table_lookup(Death1, <<"count">>)),
-    ?assertEqual({array, [{longstr, Q1}, {longstr, <<"other key">>}]},
+    %% routing-keys in the death history should include CC but exclude BCC keys
+    ?assertEqual({array, [{longstr, Q1},
+                          {longstr, <<"cc 1">>},
+                          {longstr, <<"cc 2">>}]},
                  rabbit_misc:table_lookup(Death1, <<"routing-keys">>)),
     ?assertEqual({longstr, <<"0">>}, rabbit_misc:table_lookup(Death1, <<"original-expiration">>)),
     {timestamp, T1} = rabbit_misc:table_lookup(Death1, <<"time">>),