fix(rust/cardano-chain-follower): Check condition for Block Roll Forward (#56)

* fix(rust/cardano-chain-follower): fix follow chain example argument name

* fix(rust/cardano-chain-follower): explicit condition for block roll forward

Author: saibatizoku

rust/cardano-chain-follower/examples/follow_chains.rs

@@ -111,7 +111,7 @@ async fn start_sync_for(network: &Network, matches: ArgMatches) -> Result<(), Bo
         mithril_dl_connect_timeout = format!("{}", humantime::format_duration(connect_timeout));
     }
 
-    if let Some(data_timeout) = matches.get_one::<u64>("mithril-sync-data-timeout") {
+    if let Some(data_timeout) = matches.get_one::<u64>("mithril-sync-data-read-timeout") {
         dl_config = dl_config.with_connection_timeout(Duration::from_secs(*data_timeout));
     }
     if let Some(data_timeout) = dl_config.data_read_timeout {

rust/cardano-chain-follower/src/follow.rs

@@ -109,9 +109,13 @@ impl ChainFollower {
             }
         }
 
-        if (self.mithril_tip.is_none() || current_mithril_tip > self.mithril_tip)
-            && self.current < self.mithril_tip
-        {
+        let roll_forward_condition = if let Some(mithril_tip) = &self.mithril_tip {
+            current_mithril_tip > *mithril_tip && *mithril_tip > self.current
+        } else {
+            true
+        };
+
+        if roll_forward_condition {
             let snapshot = MithrilSnapshot::new(self.chain);
             if let Some(block) = snapshot.read_block_at(&current_mithril_tip).await {
                 // The Mithril Tip has moved forwards.