From 859d4db87e376d71bec97cbda145c446c858d83a Mon Sep 17 00:00:00 2001
From: "mergify[bot]" <37929162+mergify[bot]@users.noreply.github.com>
Date: Fri, 15 May 2020 14:36:54 -0700
Subject: [PATCH] validator: Forge a confirmed root before halting for RPC
 inspection (bp #10061) (#10066)

* Forge a confirmed root before halting for RPC inspection (#10061)

(cherry picked from commit 1da16679203c55ba4b1d9eea0c566db69f948f1a)

# Conflicts:
#	core/src/commitment.rs

* Update commitment.rs

Co-authored-by: Michael Vines <mvines@gmail.com>
---
 core/src/commitment.rs | 1 -
 core/src/validator.rs  | 7 +++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/core/src/commitment.rs b/core/src/commitment.rs
index ea1bdf463c..2f945d51c6 100644
--- a/core/src/commitment.rs
+++ b/core/src/commitment.rs
@@ -162,7 +162,6 @@ impl BlockCommitmentCache {
         }
     }
 
-    #[cfg(test)]
     pub(crate) fn set_get_largest_confirmed_root(&mut self, root: Slot) {
         self.largest_confirmed_root = root;
     }
diff --git a/core/src/validator.rs b/core/src/validator.rs
index f669f23aa4..9bb2177559 100644
--- a/core/src/validator.rs
+++ b/core/src/validator.rs
@@ -314,6 +314,13 @@ 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();