handle false-positive txid index hit

src/tracker.rs

@@ -105,7 +105,7 @@ impl Tracker {
     ) -> Result<Option<(BlockHash, Transaction)>> {
         // Note: there are two blocks with coinbase transactions having same txid (see BIP-30)
         let blockhashes = self.index.filter_by_txid(txid);
-        let result = daemon
+        Ok(daemon
             .for_blocks(blockhashes, |blockhash, block| {
                 let mut visitor = FindTransaction::new(txid);
                 match bsl::Block::visit(&block, &mut visitor) {
@@ -114,9 +114,8 @@ impl Tracker {
                 }
                 visitor.tx_found().map(|tx| (blockhash, tx))
             })?
-            .first()
-            .cloned()
-            .flatten();
-        Ok(result)
+            .into_iter()
+            .filter_map(|e| e) // skip non-matching blocks, in case of a false-positive index hit
+            .next()) // return first match
     }
 }