Forge a confirmed root before halting for RPC inspection

core/src/commitment.rs

@@ -180,7 +180,6 @@ impl BlockCommitmentCache {
  }
  }
 
- #[cfg(test)]
  pub(crate) fn set_get_largest_confirmed_root(&mut self, root: Slot) {
  self.largest_confirmed_root = root;
  }

core/src/validator.rs

@@ -304,6 +304,13 @@ impl Validator {
  );
 
  if config.dev_halt_at_slot.is_some() {
+ // Simulate a confirmed root to avoid RPC errors with CommitmentmentConfig::max() and
+ // to ensure RPC endpoints like getConfirmedBlock, which require a confirmed root, work
+ block_commitment_cache
+ .write()
+ .unwrap()
+ .set_get_largest_confirmed_root(bank_forks.read().unwrap().root());
+
  // Park with the RPC service running, ready for inspection!
  warn!("Validator halted");
  std::thread::park();