Fix document deletion followed by creation

If the updater collects 2 updates for the same document
where the first deletes it and the second creates it, it
would send a conflict error to the client of the create
request. This wouldn't happen if the 2 requests were
collected in 2 different batches by the updater.

Closes COUCHDB-188

2 files changed, 72 insertions, 12 deletions

diff --git a/src/couchdb/couch_db_updater.erl b/src/couchdb/couch_db_updater.erl
index e57f05bcc..0b890fe2c 100644
--- a/src/couchdb/couch_db_updater.erl
+++ b/src/couchdb/couch_db_updater.erl
@@ -576,16 +576,16 @@ merge_rev_trees(_Limit, _Merge, [], [], AccNewInfos, AccRemoveSeqs, AccSeq) ->
     {ok, lists:reverse(AccNewInfos), AccRemoveSeqs, AccSeq};
 merge_rev_trees(Limit, MergeConflicts, [NewDocs|RestDocsList],
         [OldDocInfo|RestOldInfo], AccNewInfos, AccRemoveSeqs, AccSeq) ->
-    #full_doc_info{id=Id,rev_tree=OldTree,deleted=OldDeleted,update_seq=OldSeq}
+    #full_doc_info{id=Id,rev_tree=OldTree,deleted=OldDeleted0,update_seq=OldSeq}
             = OldDocInfo,
-    NewRevTree = lists:foldl(
-        fun({Client, {#doc{revs={Pos,[_Rev|PrevRevs]}}=NewDoc, Ref}}, AccTree) ->
+    {NewRevTree, _} = lists:foldl(
+        fun({Client, {#doc{revs={Pos,[_Rev|PrevRevs]}}=NewDoc, Ref}}, {AccTree, OldDeleted}) ->
             if not MergeConflicts ->
                 case couch_key_tree:merge(AccTree, couch_doc:to_path(NewDoc),
                     Limit) of
                 {_NewTree, conflicts} when (not OldDeleted) ->
                     send_result(Client, Ref, conflict),
-                    AccTree;
+                    {AccTree, OldDeleted};
                 {NewTree, conflicts} when PrevRevs /= [] ->
                     % Check to be sure if prev revision was specified, it's
                     % a leaf node in the tree
@@ -594,10 +594,10 @@ merge_rev_trees(Limit, MergeConflicts, [NewDocs|RestDocsList],
                             {LeafPos, LeafRevId} == {Pos-1, hd(PrevRevs)}
                         end, Leafs),
                     if IsPrevLeaf ->
-                        NewTree;
+                        {NewTree, OldDeleted};
                     true ->
                         send_result(Client, Ref, conflict),
-                        AccTree
+                        {NewTree, OldDeleted}
                     end;
                 {NewTree, no_conflicts} when  AccTree == NewTree ->
                     % the tree didn't change at all
@@ -616,21 +616,21 @@ merge_rev_trees(Limit, MergeConflicts, [NewDocs|RestDocsList],
                                 couch_doc:to_path(NewDoc2), Limit),
                         % we changed the rev id, this tells the caller we did
                         send_result(Client, Ref, {ok, {OldPos + 1, NewRevId}}),
-                        NewTree2;
+                        {NewTree2, OldDeleted};
                     true ->
                         send_result(Client, Ref, conflict),
-                        AccTree
+                        {NewTree, OldDeleted}
                     end;
                 {NewTree, _} ->
-                    NewTree
+                    {NewTree, NewDoc#doc.deleted}
                 end;
             true ->
                 {NewTree, _} = couch_key_tree:merge(AccTree,
                             couch_doc:to_path(NewDoc), Limit),
-                NewTree
+                {NewTree, OldDeleted}
             end
         end,
-        OldTree, NewDocs),
+        {OldTree, OldDeleted0}, NewDocs),
     if NewRevTree == OldTree ->
         % nothing changed
         merge_rev_trees(Limit, MergeConflicts, RestDocsList, RestOldInfo,
diff --git a/test/etap/074-doc-update-conflicts.t b/test/etap/074-doc-update-conflicts.t
index 7c2f80d82..09d063313 100755
--- a/test/etap/074-doc-update-conflicts.t
+++ b/test/etap/074-doc-update-conflicts.t
@@ -26,7 +26,7 @@ test_db_name() -> <<"couch_test_update_conflicts">>.
 main(_) ->
     test_util:init_code_path(),
 
-    etap:plan(25),
+    etap:plan(35),
     case (catch test()) of
         ok ->
             etap:end_tests();
@@ -45,6 +45,8 @@ test() ->
         fun(NumClients) -> test_concurrent_doc_update(NumClients) end,
         [100, 500, 1000, 2000, 5000]),
 
+    test_bulk_delete_create(),
+
     couch_server_sup:stop(),
     ok.
 
@@ -132,6 +134,64 @@ test_concurrent_doc_update(NumClients) ->
     delete_db(Db3).
 
 
+% COUCHDB-188
+test_bulk_delete_create() ->
+    {ok, Db} = create_db(test_db_name()),
+    Doc = couch_doc:from_json_obj({[
+        {<<"_id">>, <<"foobar">>},
+        {<<"value">>, 0}
+    ]}),
+    {ok, Rev} = couch_db:update_doc(Db, Doc, []),
+
+    DeletedDoc = couch_doc:from_json_obj({[
+        {<<"_id">>, <<"foobar">>},
+        {<<"_rev">>, couch_doc:rev_to_str(Rev)},
+        {<<"_deleted">>, true}
+    ]}),
+    NewDoc = couch_doc:from_json_obj({[
+        {<<"_id">>, <<"foobar">>},
+        {<<"value">>, 666}
+    ]}),
+
+    {ok, Results} = couch_db:update_docs(Db, [DeletedDoc, NewDoc], []),
+    ok = couch_db:close(Db),
+
+    etap:is(length([ok || {ok, _} <- Results]), 2,
+        "Deleted and non-deleted versions got an ok reply"),
+
+    [{ok, Rev1}, {ok, Rev2}] = Results,
+    {ok, Db2} = couch_db:open_int(test_db_name(), []),
+
+    {ok, [{ok, Doc1}]} = couch_db:open_doc_revs(
+        Db2, <<"foobar">>, [Rev1], [conflicts, deleted_conflicts]),
+    {ok, [{ok, Doc2}]} = couch_db:open_doc_revs(
+        Db2, <<"foobar">>, [Rev2], [conflicts, deleted_conflicts]),
+    ok = couch_db:close(Db2),
+
+    {Doc1Props} = couch_doc:to_json_obj(Doc1, []),
+    {Doc2Props} = couch_doc:to_json_obj(Doc2, []),
+
+    etap:is(couch_util:get_value(<<"_deleted">>, Doc1Props), true,
+        "Document was deleted"),
+    etap:is(couch_util:get_value(<<"_deleted">>, Doc2Props), undefined,
+        "New document not flagged as deleted"),
+    etap:is(couch_util:get_value(<<"value">>, Doc2Props), 666,
+        "New leaf revision has the right value"),
+    etap:is(couch_util:get_value(<<"_conflicts">>, Doc1Props), undefined,
+        "Deleted document has no conflicts"),
+    etap:is(couch_util:get_value(<<"_deleted_conflicts">>, Doc1Props), undefined,
+        "Deleted document has no deleted conflicts"),
+    etap:is(couch_util:get_value(<<"_conflicts">>, Doc2Props), undefined,
+        "New leaf revision doesn't have conflicts"),
+    etap:is(couch_util:get_value(<<"_deleted_conflicts">>, Doc2Props), undefined,
+        "New leaf revision doesn't have deleted conflicts"),
+
+    etap:is(element(1, Rev1), 2, "Deleted revision has position 2"),
+    etap:is(element(1, Rev2), 1, "New leaf revision has position 1"),
+
+    delete_db(Db2).
+
+
 spawn_client(Doc) ->
     spawn(fun() ->
         {ok, Db} = couch_db:open_int(test_db_name(), []),