1 files changed, 32 insertions, 0 deletions

diff --git a/src/rpc.cpp b/src/rpc.cpp
index 8a0d112..da22b1d 100644
--- a/src/rpc.cpp
+++ b/src/rpc.cpp
@@ -180,6 +180,38 @@ static bool RebuildJob()
             return false;
         }
 
+        // The comparison above is blind in the one case that matters most.
+        //
+        // When the node goes deaf -- peers still in vNodes, nothing arriving --
+        // no peer announces anything, GetPeerMedianHeight() returns -1, and the
+        // fallback ("nobody has told us anything, so mine our best chain") let
+        // the pool build a private fork for as long as the deafness lasted.
+        // That fallback is right for a node that has simply not been told yet
+        // and wrong for a node that has stopped being able to hear, and a
+        // height nobody sent cannot tell those apart. Time can.
+        //
+        // Deliberately not behind a debug category, and deliberately not a
+        // silent refusal: an operator whose pool has stopped issuing jobs needs
+        // the reason in the log. /poolmineblind is the escape hatch for a node
+        // that really is alone -- without one, a genuinely isolated pool that is
+        // the majority of the hashrate could never restart its own chain, which
+        // is the deadlock the tip-age check used to cause.
+        if (nPeerHeight < 0 && !fPoolMineBlind) {
+            int64 nAge = GetPeerHeightAgeSecs();
+            if (nAge >= BTF_NO_PEER_HEIGHT_MAX_SECS) {
+                static int64 nLastSaid = 0;
+                if (GetTime() - nLastSaid > 60) {
+                    nLastSaid = GetTime();
+                    printf("RebuildJob: no peer has reported a height for %d minutes "
+                           "-- not issuing jobs (our height %d, %d peers connected). "
+                           "This node is deaf; mining now would fork it. "
+                           "Pass /poolmineblind to override.\n",
+                           (int)(nAge / 60), nBestHeight, (int)vNodes.size());
+                }
+                return false;
+            }
+        }
+
         CBlockIndex* pindexPrev = pindexBest;
         unsigned int nBits = GetNextWorkRequired(pindexPrev);