[couchdb] 01/01: TODO - write this commit message

[da...@apache.org]

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davisp pushed a commit to branch fix-open-doc-revs-read-repair
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit fcdd7e8c5d7761bf6690e14173601a80c2fb57f2
Author: Paul J. Davis <pa...@gmail.com>
AuthorDate: Mon Jan 14 18:32:34 2019 -0600

    TODO - write this commit message
---
 src/fabric/src/fabric_doc_open_revs.erl | 57 ++++++++++++++++++++++-----------
 1 file changed, 39 insertions(+), 18 deletions(-)

diff --git a/src/fabric/src/fabric_doc_open_revs.erl b/src/fabric/src/fabric_doc_open_revs.erl
index 15b8eac..91426cf 100644
--- a/src/fabric/src/fabric_doc_open_revs.erl
+++ b/src/fabric/src/fabric_doc_open_revs.erl
@@ -243,8 +243,7 @@ format_reply(true, Replies, _) ->
     tree_format_replies(Replies);
 
 format_reply(false, Replies, _) ->
-    Filtered = filter_reply(Replies),
-    dict_format_replies(Filtered).
+    dict_format_replies(Replies).
 
 
 tree_format_replies(RevTree) ->
@@ -260,22 +259,44 @@ tree_format_replies(RevTree) ->
 
 
 dict_format_replies(Dict) ->
-    lists:sort([Reply || {_, {Reply, _}} <- Dict]).
-
-filter_reply(Replies) ->
-    AllFoundRevs = lists:foldl(fun
-        ({{{not_found, missing}, _}, _}, Acc) ->
-            Acc;
-        ({{_, {Pos, [Rev | _]}}, _}, Acc) ->
-            [{Pos, Rev} | Acc]
-    end, [], Replies),
-    %% keep not_found replies only for the revs that don't also have doc reply
-    lists:filter(fun
-        ({{{not_found, missing}, Rev}, _}) ->
-            not lists:member(Rev, AllFoundRevs);
-        (_) ->
-            true
-    end, Replies).
+    Replies0 = [Reply || {_, {Reply, _}} <- Dict],
+
+    AllFoundRevs = lists:foldl(fun(Reply, Acc) ->
+        case Reply of
+            {ok, #doc{revs = {Pos, [RevId | _]}}} ->
+                [{Pos, RevId} | Acc];
+            _ ->
+                Acc
+        end
+    end, [], Replies0),
+
+    %% Drop any not_found replies for which we
+    %% found the revision on a different node.
+    Replies1 = lists:filter(fun(Reply) ->
+        case Reply of
+            {{not_found, missing}, Rev} ->
+                not lists:member(Rev, AllFoundRevs);
+            _ ->
+                true
+        end
+    end,
+
+    Replies2 = lists:sort(Replies1),
+    collapse_duplicate_revs(Replies2).
+
+
+collapse_duplicate_revs([{ok, Doc1}, {ok, Doc2} | Rest]) ->
+    {D1, R1} = Doc1#doc.revs,
+    {D2, R2} = Doc2#doc.revs,
+    Head = case D1 == D2 and lists:prefix(R1, R2) of
+        true -> [];
+        false -> [{ok, Doc1}]
+    end,
+    Head ++ collapse_duplicate_revs([{ok, Doc2} | Rest]),
+
+collapse_duplicate_revs([Reply | Rest]) ->
+    [Reply | collapse_duplicate_revs(Rest)].
+
 
 -ifdef(TEST).
 -include_lib("eunit/include/eunit.hrl").