Fix case clause error in replicator _scheduler/docs response

When a job is completing, there is a period of time when the document isn't
updated yet with the state, and it's also not present in the scheduler ets
table. In that case we return `nil`, but we don't account for that case in the
_scheduler/docs fabric calls.

To fix it, account for `nil` whenever we get the doc state.

src/couch_replicator/src/couch_replicator_fabric.erl

@@ -18,7 +18,6 @@
 
 -include_lib("fabric/include/fabric.hrl").
 -include_lib("mem3/include/mem3.hrl").
--include_lib("couch/include/couch_db.hrl").
 -include_lib("couch_mrview/include/couch_mrview.hrl").
 
 docs(DbName, Options, QueryArgs, Callback, Acc) ->
@@ -167,6 +166,9 @@ maybe_fetch_and_filter_doc(Id, undecided, State) ->
  {ok, {Props} = DocInfo} ->
  DocState = couch_util:get_value(state, Props),
  couch_replicator_utils:filter_state(DocState, FilterStates, DocInfo);
+ {ok, nil} ->
+ % could have just completed
+ skip;
  {error, not_found} ->
  % could have been deleted
  skip

src/couch_replicator/src/couch_replicator_fabric_rpc.erl

@@ -17,7 +17,6 @@
 ]).
 
 -include_lib("fabric/include/fabric.hrl").
--include_lib("couch/include/couch_db.hrl").
 -include_lib("couch_mrview/include/couch_mrview.hrl").
 
 docs(DbName, Options, Args0) ->
@@ -80,6 +79,10 @@ rep_doc_state(Shard, Id, {[_ | _]} = Doc, States, HealthThreshold) ->
  HealthThreshold
  )
  of
+ {ok, nil} ->
+ % Could have been just completed. Let the coordinator
+ % try to refetch it.
+ undecided;
  {ok, EtsInfo} ->
  State = get_doc_state(EtsInfo),
  couch_replicator_utils:filter_state(State, States, EtsInfo);

src/couch_replicator/test/eunit/couch_replicator_scheduler_docs_tests.erl

@@ -133,10 +133,7 @@ t_scheduler_docs_total_rows({_Ctx, {RepDb, Source, Target}}) ->
  case req(get, SchedulerDocsUrl) of
  {200, #{<<"docs">> := [_ | _]} = Decoded} ->
  Decoded;
- {_, #{<<"error">> := Error, <<"reason">> := Reason}} ->
- ?debugVal(Error, 100),
- ?debugVal(binary_to_list(Reason), 100);
- {_, #{}} ->
+ {200, #{<<"docs">> := []}} ->
  wait
  end
  end,