From c95bbbf355abbc6d5854ab1d30b6e07ceda5ed97 Mon Sep 17 00:00:00 2001
From: Jude Nelson <judecn@gmail.com>
Date: Mon, 28 Jun 2021 14:36:24 -0400
Subject: [PATCH] fix: address #2713 by starting processing from the first
 burnchain block of the reward cycle in which the canonical Stacks chain state
 starts

---
 testnet/stacks-node/src/run_loop/neon.rs | 29 +++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/testnet/stacks-node/src/run_loop/neon.rs b/testnet/stacks-node/src/run_loop/neon.rs
index 613b4552b..dbecf22ba 100644
--- a/testnet/stacks-node/src/run_loop/neon.rs
+++ b/testnet/stacks-node/src/run_loop/neon.rs
@@ -314,7 +314,27 @@ impl RunLoop {
         };
 
         // TODO (hack) instantiate the sortdb in the burnchain
-        let _ = burnchain.sortdb_mut();
+        let sortdb = burnchain.sortdb_mut();
+        let mut block_height = {
+            let (stacks_ch, _) = SortitionDB::get_canonical_stacks_chain_tip_hash(sortdb.conn())
+                .expect("BUG: failed to load canonical stacks chain tip hash");
+
+            match SortitionDB::get_block_snapshot_consensus(sortdb.conn(), &stacks_ch)
+                .expect("BUG: failed to query sortition DB")
+            {
+                Some(sn) => burnchain_config.reward_cycle_to_block_height(
+                    burnchain_config
+                        .block_height_to_reward_cycle(sn.block_height)
+                        .expect("BUG: snapshot preceeds first reward cycle"),
+                ),
+                None => {
+                    let sn = SortitionDB::get_first_block_snapshot(&sortdb.conn())
+                        .expect("BUG: failed to get first-ever block snapshot");
+
+                    sn.block_height
+                }
+            }
+        };
 
         // Start the runloop
         trace!("Begin run loop");
@@ -330,8 +350,6 @@ impl RunLoop {
                 .unwrap();
         }
 
-        let mut block_height = 1.max(burnchain_config.first_block_height);
-
         let mut burnchain_height = block_height;
         let mut num_sortitions_in_last_cycle = 1;
         let mut learned_burnchain_height = false;
@@ -339,6 +357,11 @@ impl RunLoop {
         // prepare to fetch the first reward cycle!
         target_burnchain_block_height = burnchain_height + pox_constants.reward_cycle_length as u64;
 
+        debug!(
+            "Begin main runloop starting a burnchain block {}",
+            block_height
+        );
+
         loop {
             // Orchestrating graceful termination
             if !should_keep_running.load(Ordering::SeqCst) {