Fix importwallet edge case rescan bug

Start importwallet rescans at the first block with timestamp greater or equal
to the wallet birthday instead of the last block with timestamp less or equal.
This fixes an edge case bug where importwallet could fail to start the rescan
early enough if there are blocks with decreasing timestamps or multiple blocks
with the same timestamp.

1 files changed, 3 insertions, 6 deletions

diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
index 82708dab26..d46cf69efb 100644
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -536,14 +536,11 @@ UniValue importwallet(const JSONRPCRequest& request)
     }
     file.close();
     pwallet->ShowProgress("", 100); // hide progress dialog in GUI
-
-    CBlockIndex *pindex = chainActive.Tip();
-    while (pindex && pindex->pprev && pindex->GetBlockTime() > nTimeBegin - TIMESTAMP_WINDOW)
-        pindex = pindex->pprev;
-
     pwallet->UpdateTimeFirstKey(nTimeBegin);
 
-    LogPrintf("Rescanning last %i blocks\n", chainActive.Height() - pindex->nHeight + 1);
+    CBlockIndex *pindex = chainActive.FindEarliestAtLeast(nTimeBegin - TIMESTAMP_WINDOW);
+
+    LogPrintf("Rescanning last %i blocks\n", pindex ? chainActive.Height() - pindex->nHeight + 1 : 0);
     pwallet->ScanForWalletTransactions(pindex);
     pwallet->MarkDirty();