From ee2a7c4ef3af6a56da5da302a39657d1fb58dc1a Mon Sep 17 00:00:00 2001
From: Julien Maffre <42961061+jumaffre@users.noreply.github.com>
Date: Wed, 26 Aug 2020 10:58:16 +0100
Subject: [PATCH] Fix Raft term history on backup (#1531)

---
 src/consensus/raft/raft.h | 15 ++++++++++++++-
 tests/e2e_logging.py      | 14 ++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/consensus/raft/raft.h b/src/consensus/raft/raft.h
index 10c98e342b..45eaeb1107 100644
--- a/src/consensus/raft/raft.h
+++ b/src/consensus/raft/raft.h
@@ -546,6 +546,7 @@ namespace raft
         LOG_FAIL_FMT(err.what());
         return;
       }
+
       LOG_DEBUG_FMT(
         "Received pt: {} pi: {} t: {} i: {}",
         r.prev_term,
@@ -618,7 +619,7 @@ namespace raft
       if (r.prev_idx < commit_idx)
       {
         LOG_DEBUG_FMT(
-          "Recv append entries to {} from {} but prev_idex ({}) < commit_idx "
+          "Recv append entries to {} from {} but prev_idx ({}) < commit_idx "
           "({})",
           local_id,
           r.from_node,
@@ -684,22 +685,34 @@ namespace raft
         switch (deserialise_success)
         {
           case kv::DeserialiseSuccess::FAILED:
+          {
             throw std::logic_error(
               "Follower failed to apply log entry " + std::to_string(i));
             break;
+          }
 
           case kv::DeserialiseSuccess::PASS_SIGNATURE:
+          {
             LOG_DEBUG_FMT("Deserialising signature at {}", i);
             committable_indices.push_back(i);
+
             if (sig_term)
+            {
               term_history.update(commit_idx + 1, sig_term);
+              commit_if_possible(r.leader_commit_idx);
+            }
             break;
+          }
 
           case kv::DeserialiseSuccess::PASS:
+          {
             break;
+          }
 
           default:
+          {
             throw std::logic_error("Unknown DeserialiseSuccess value");
+          }
         }
       }
 
diff --git a/tests/e2e_logging.py b/tests/e2e_logging.py
index 45c9fbdcdb..f7fb8f9daa 100644
--- a/tests/e2e_logging.py
+++ b/tests/e2e_logging.py
@@ -445,6 +445,8 @@ def test_view_history(network, args):
 
     check = infra.checker.Checker()
 
+    previous_node = None
+    previous_tx_ids = ""
     for node in network.get_joined_nodes():
         with node.client("user0") as c:
             r = c.get("/node/commit")
@@ -491,6 +493,18 @@ def test_view_history(network, args):
                     f"Node {node.node_id}: Incomplete or inconsistent view history"
                 )
 
+            # Compare view history between nodes
+            if previous_tx_ids:
+                # Some nodes may have a slightly longer view history so only compare the common prefix
+                min_tx_ids_len = min(len(previous_tx_ids), len(tx_ids_condensed))
+                assert (
+                    tx_ids_condensed[:min_tx_ids_len]
+                    == previous_tx_ids[:min_tx_ids_len]
+                ), f"Tx IDs don't match between node {node.node_id} and node {previous_node.node_id}: {tx_ids_condensed[:min_tx_ids_len]} and {previous_tx_ids[:min_tx_ids_len]}"
+
+            previous_tx_ids = tx_ids_condensed
+            previous_node = node
+
     return network