wallet: fast rescan: show log message for every non-skipped block

For that purpose, a new logging category BCLog::SCAN is introduced.

src/logging.cpp

@@ -181,6 +181,7 @@ const CLogCategoryDesc LogCategories[] =
     {BCLog::UTIL, "util"},
     {BCLog::BLOCKSTORE, "blockstorage"},
     {BCLog::TXRECONCILIATION, "txreconciliation"},
+    {BCLog::SCAN, "scan"},
     {BCLog::ALL, "1"},
     {BCLog::ALL, "all"},
 };
@@ -283,6 +284,8 @@ std::string LogCategoryToStr(BCLog::LogFlags category)
         return "blockstorage";
     case BCLog::LogFlags::TXRECONCILIATION:
         return "txreconciliation";
+    case BCLog::LogFlags::SCAN:
+        return "scan";
     case BCLog::LogFlags::ALL:
         return "all";
     }

src/logging.h

@@ -67,6 +67,7 @@ namespace BCLog {
         UTIL        = (1 << 25),
         BLOCKSTORE  = (1 << 26),
         TXRECONCILIATION = (1 << 27),
+        SCAN        = (1 << 28),
         ALL         = ~(uint32_t)0,
     };
     enum class Level {

src/wallet/wallet.cpp

@@ -1849,10 +1849,16 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
         if (fast_rescan_filter) {
             fast_rescan_filter->UpdateIfNeeded();
             auto matches_block{fast_rescan_filter->MatchesBlock(block_hash)};
-            if (matches_block.has_value() && !*matches_block) {
+            if (matches_block.has_value()) {
-                result.last_scanned_block = block_hash;
+                if (*matches_block) {
-                result.last_scanned_height = block_height;
+                    LogPrint(BCLog::SCAN, "Fast rescan: inspect block %d [%s] (filter matched)\n", block_height, block_hash.ToString());
-                fetch_block = false;
+                } else {
+                    result.last_scanned_block = block_hash;
+                    result.last_scanned_height = block_height;
+                    fetch_block = false;
+                }
+            } else {
+                LogPrint(BCLog::SCAN, "Fast rescan: inspect block %d [%s] (WARNING: block filter not found!)\n", block_height, block_hash.ToString());
             }
         }