Partial fix for bug in last commit, but not good enough

prototype/corfurl/src/corfurl_client.erl

@@ -18,11 +18,6 @@
 %%
 %% -------------------------------------------------------------------
 
-%% TODO: fix this failure case with append_page(Bin) -> {ok, 2},
-%%       but read_page(LPN=1) can read Bin, and model believes that
-%%       LPN=1 was never written
-%% Ca = [{2,2,1},{{[{set,{var,1},{call,corfurl_pulse,setup,[2,2,1,standard]}}],[[{set,{var,3},{call,corfurl_pulse,append,[{var,1},<<0>>]}}],[{set,{var,2},{call,corfurl_pulse,stop_sequencer,[{var,1},kill]}},{set,{var,4},{call,corfurl_pulse,trim,[{var,1},386862782]}},{set,{var,5},{call,corfurl_pulse,scan_forward,[{var,1},5412106233,1]}}]]},{24672,25300,90107}},[{events,[[{no_bad_reads,[]}]]}]].
-
 -module(corfurl_client).
 
 -export([append_page/2, read_page/2, fill_page/2, trim_page/2, scan_forward/3]).
@@ -40,22 +35,8 @@ append_page(Proj, _Page, 0) ->
     {{error_failed, ?MODULE, ?LINE}, Proj};
 append_page(#proj{seq={Sequencer,_,_}} = Proj, Page, Retries) ->
     try
-        case corfurl_sequencer:get(Sequencer, 1) of
+        {ok, LPN} = corfurl_sequencer:get(Sequencer, 1),
-            {ok, LPN} ->
+        append_page1(Proj, LPN, Page, 5)
-                case append_page2(Proj, LPN, Page) of
-                    lost_race ->
-                        append_page(Proj, Page, Retries - 1);
-                    error_badepoch ->
-                        case poll_for_new_epoch_projection(Proj) of
-                            {ok, NewProj} ->
-                                append_page(NewProj, Page, Retries - 1);
-                            Else ->
-                                {Else, Proj}
-                        end;
-                    Else ->
-                        {Else, Proj}
-                end
-        end
     catch
         exit:{Reason,{_gen_server_or_pulse_gen_server,call,[Sequencer|_]}}
           when Reason == noproc; Reason == normal ->
@@ -64,6 +45,23 @@ append_page(#proj{seq={Sequencer,_,_}} = Proj, Page, Retries) ->
             {{error_failed, ?MODULE, ?LINE}, incomplete_code, Exit}
     end.
 
+append_page1(Proj, _LPN, _Page, 0) ->
+    {{error_failed, ?MODULE, ?LINE}, Proj};
+append_page1(Proj, LPN, Page, Retries) ->
+    case append_page2(Proj, LPN, Page) of
+        lost_race ->
+            append_page(Proj, Page, Retries - 1);
+        error_badepoch ->
+            case poll_for_new_epoch_projection(Proj) of
+                {ok, NewProj} ->
+                    append_page1(NewProj, LPN, Page, Retries - 1);
+                Else ->
+                    {Else, Proj}
+            end;
+        Else ->
+            {Else, Proj}
+    end.
+
 append_page2(Proj, LPN, Page) ->
     case corfurl:write_page(Proj, LPN, Page) of
         ok ->