client: if an output file is missing or bad length, mark WU as error

Failure to do so apparently leaves WU in limbo

client/app.cpp

@@ -273,6 +273,9 @@ void ACTIVE_TASK::cleanup_task() {
     kill_subsidiary_processes();
 
     if (cc_config.exit_after_finish) {
+        msg_printf(wup->project, MSG_INFO,
+            "exit_after_finish: job %s, slot %d", wup->name, slot
+        );
         gstate.write_state_file();
         exit(0);
     }

client/client_types.cpp

@@ -1133,11 +1133,13 @@ int WORKUNIT::parse(XML_PARSER& xp) {
         if (xp.parse_double("rsc_disk_bound", rsc_disk_bound)) continue;
         if (xp.match_tag("file_ref")) {
             retval = file_ref.parse(xp);
-            if (retval) msg_printf(0, MSG_INFO,
-                "can't parse file_ref in workunit: %s",
-                boincerror(retval)
-            );
-            return retval;
+            if (retval) {
+                msg_printf(0, MSG_INFO,
+                    "can't parse file_ref in workunit: %s",
+                    boincerror(retval)
+                );
+                return retval;
+            }
 #ifndef SIM
             input_files.push_back(file_ref);
 #endif

client/cs_files.cpp

@@ -506,6 +506,15 @@ void CLIENT_STATE::check_file_existence() {
                     path, fip->nbytes, size
                 );
             }
+
+            // If an output file disappears before it's uploaded,
+            // flag the job as an error.
+            //
+            if (fip->result && fip->status == FILE_NOT_PRESENT && !fip->uploaded) {
+                gstate.report_result_error(
+                    *fip->result, "output file missing or invalid"
+                );
+            }
         }
     }
 }