bugfix: break ActivateBestChain() differently on shutdown

Moves the break in ActivateBestChain() when a node is being shut
down from the beginning of the loop block to the end, allowing
pindexNewTip to be populated with chainActive.Tip() rather than
its initial NULL value. Solves issues when shutting down nodes
while inside the ActivateBestChain loop.

1 files changed, 9 insertions, 3 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index 46e586415..35778a2e7 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2504,9 +2504,6 @@ bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams,
     CBlockIndex *pindexMostWork = NULL;
     CBlockIndex *pindexNewTip = NULL;
     do {
-        boost::this_thread::interruption_point();
-        if (ShutdownRequested())
-            break;
 
         const CBlockIndex *pindexFork;
         ConnectTrace connectTrace;
@@ -2566,6 +2563,15 @@ bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams,
         if (pindexFork != pindexNewTip) {
             uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
         }
+
+        // Perform the shutdown detection to the end of the loop to prevent
+        // pindexNewTip being nil
+        boost::this_thread::interruption_point();
+        if (ShutdownRequested()) {
+            LogPrintf("ActivateBestChain: shutdown requested, breaking loop\n");
+            break;
+        }
+
     } while (pindexNewTip != pindexMostWork);
     CheckBlockIndex(chainparams.GetConsensus(pindexNewTip->nHeight));