consensus: from v12, enforce >= 2 outputs

src/rpc/core_rpc_server.cpp

@@ -875,6 +875,8 @@ namespace cryptonote
         add_reason(reason, "fee too low");
       if ((res.not_rct = tvc.m_not_rct))
         add_reason(reason, "tx is not ringct");
+      if ((res.too_few_outputs = tvc.m_too_few_outputs))
+        add_reason(reason, "too few outputs");
       const std::string punctuation = reason.empty() ? "" : ": ";
       if (tvc.m_verifivation_failed)
       {

src/rpc/core_rpc_server_commands_defs.h

@@ -609,6 +609,7 @@ namespace cryptonote
       bool overspend;
       bool fee_too_low;
       bool not_rct;
+      bool too_few_outputs;
       bool sanity_check_failed;
       bool untrusted;
 
@@ -624,6 +625,7 @@ namespace cryptonote
         KV_SERIALIZE(overspend)
         KV_SERIALIZE(fee_too_low)
         KV_SERIALIZE(not_rct)
+        KV_SERIALIZE(too_few_outputs)
         KV_SERIALIZE(sanity_check_failed)
         KV_SERIALIZE(untrusted)
       END_KV_SERIALIZE_MAP()

src/rpc/daemon_handler.cpp

@@ -343,6 +343,11 @@ namespace rpc
         if (!res.error_details.empty()) res.error_details += " and ";
         res.error_details = "tx is not ringct";
       }
+      if (tvc.m_too_few_outputs)
+      {
+        if (!res.error_details.empty()) res.error_details += " and ";
+        res.error_details = "too few outputs";
+      }
       if (res.error_details.empty())
       {
         res.error_details = "an unknown issue was found with the transaction";