1 files changed, 23 insertions, 0 deletions

diff --git a/src/rpc.cpp b/src/rpc.cpp
index a4b53ca..cc3fffa 100644
--- a/src/rpc.cpp
+++ b/src/rpc.cpp
@@ -223,6 +223,29 @@ static bool RebuildJob()
         // From the pool, so the template's payout key is in wallet.dat before
         // any miner is handed work against it.
         vector<unsigned char> vchPubKey = GetKeyFromPool();
+        if (vchPubKey.empty()) {
+            // Empty means the wallet could not produce a key: encrypted and
+            // locked, or key generation itself failed. Serialised, an empty
+            // vector is a zero-length push, so the coinbase would become
+            // `<empty> OP_CHECKSIG` -- a script nobody can satisfy. Every
+            // block mined against such a job burns its whole subsidy, while
+            // QueuePayouts still records the full obligation and the miners
+            // are then paid out of coin that block never contributed.
+            // BitcoinMiner refuses to mine in this state; refuse to hand the
+            // pool's miners work in it too. printf and not LogPrint for the
+            // reason given above the deaf-node refusal, and throttled the
+            // same way -- the no-job watchdog retries every few seconds for
+            // as long as the condition lasts.
+            static int64 nLastSaidNoKey = 0;
+            if (GetTime() - nLastSaidNoKey > 60) {
+                nLastSaidNoKey = GetTime();
+                printf("RebuildJob: no wallet key available for the coinbase "
+                       "(wallet locked, or key generation failed -- the "
+                       "GetKeyFromPool line above says which) -- not issuing "
+                       "jobs\n");
+            }
+            return false;
+        }
         static std::atomic<uint32_t> sExtra{0};
         uint32_t extraNonce = ++sExtra;