Github user iilyak commented on a diff in the pull request:
https://github.com/apache/couchdb-couch/pull/229#discussion_r103788697
--- Diff: src/couch_query_servers.erl ---
@@ -142,25 +142,34 @@ os_rereduce(Lang, OsRedSrcs, KVs) ->
builtin_reduce(_Re, [], _KVs, Acc) ->
{ok, lists:reverse(Acc)};
builtin_reduce(Re, [<<"_sum",_/binary>>|BuiltinReds], KVs, Acc) ->
- Sum = builtin_sum_rows(KVs),
+ Sum = builtin_sum_rows(KVs, []),
builtin_reduce(Re, BuiltinReds, KVs, [Sum|Acc]);
builtin_reduce(reduce, [<<"_count",_/binary>>|BuiltinReds], KVs, Acc) ->
Count = length(KVs),
builtin_reduce(reduce, BuiltinReds, KVs, [Count|Acc]);
builtin_reduce(rereduce, [<<"_count",_/binary>>|BuiltinReds], KVs, Acc) ->
- Count = builtin_sum_rows(KVs),
+ Count = builtin_sum_rows(KVs, []),
builtin_reduce(rereduce, BuiltinReds, KVs, [Count|Acc]);
builtin_reduce(Re, [<<"_stats",_/binary>>|BuiltinReds], KVs, Acc) ->
Stats = builtin_stats(Re, KVs),
builtin_reduce(Re, BuiltinReds, KVs, [Stats|Acc]).
-builtin_sum_rows(KVs) ->
- lists:foldl(fun([_Key, Value], Acc) -> sum_values(Value, Acc) end, 0,
KVs).
-sum_values({Props}, 0) ->
- {Props};
-sum_values({Props}, {AccProps}) ->
- {sum_objects(lists:sort(Props), lists:sort(AccProps))};
+builtin_sum_rows([], Acc) ->
+ Acc;
+builtin_sum_rows([[Key, Value] | RestKVs], Acc) ->
+ try sum_values(Value, Acc) of
+ NewAcc ->
+ builtin_sum_rows(RestKVs, NewAcc)
+ catch
+ throw:{builtin_reduce_error, Obj} ->
+ Obj;
+ throw:{invalid_value, Reason, Cause} ->
+ {[{<<"error">>, <<"builtin_reduce_error">>},
--- End diff --
Why we have to handle the same error twice. Am I understanding it
correctly?
1. we catch invalid_value
2. we return `{[{<<"error">>, ...}]}`
3. on the outer recursion call we go into sum_values
4. sum_values detects the `{[{<<"error">>, ...}]}` and throws
`{builtin_reduce_error,...`
5. we catch `{builtin_reduce_error,...` and return Obj which is our
`{[{<<"error">>, ...}]}`
Sounds complicated.
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