corrections to handle the use of network or not and degenrate case

src/opm/output/eclipse/AggregateNetworkData.cpp

@@ -517,10 +517,10 @@ Opm::RestartIO::Helpers::WindowedArray<int>
 allocate(const std::vector<int>& inteHead)
 {
     using WV = Opm::RestartIO::Helpers::WindowedArray<int>;
-
+    int nitPrWin = std::max(static_cast<int>(entriesPerInobr(inteHead)), 1);
     return WV {
         WV::NumWindows{ 1 },
-        WV::WindowSize{ entriesPerInobr(inteHead) }
+        WV::WindowSize{ static_cast<std::size_t>(nitPrWin)  }
     };
 }
 

src/opm/output/eclipse/RestartIO.cpp

@@ -438,8 +438,10 @@ namespace {
     {
         writeGroup(sim_step, units, schedule, sumState, inteHD, rstFile);
 
-        //write network data
-        writeNetwork(es, sim_step, units, schedule, sumState, inteHD, rstFile);
+        //write network data if the network option is used
+        if (es.runspec().networkDimensions().maxNONodes() >= 1) {
+            writeNetwork(es, sim_step, units, schedule, sumState, inteHD, rstFile);
+        }
 
         // Write well and MSW data only when applicable (i.e., when present)
         const auto& wells = schedule.wellNames(sim_step);