[Tarantool-patches] [PATCH v2 4/8] box: make promote always bump the term

[Serge Petrenko]

When called without elections, promote and resulted in multiple
PROMOTE entries for the same term. This is not right, because all
the promotions for the same term except the first one would be ignored
as already seen.

Part-of #6034
---
 src/box/box.cc                                | 10 +++--
 .../gh-4114-local-space-replication.result    |  7 ++--
 .../gh-4114-local-space-replication.test.lua  |  4 +-
 .../gh-6034-promote-bump-term.result          | 37 +++++++++++++++++++
 .../gh-6034-promote-bump-term.test.lua        | 16 ++++++++
 test/replication/suite.cfg                    |  1 +
 6 files changed, 65 insertions(+), 10 deletions(-)
 create mode 100644 test/replication/gh-6034-promote-bump-term.result
 create mode 100644 test/replication/gh-6034-promote-bump-term.test.lua

diff --git a/src/box/box.cc b/src/box/box.cc
index 6a0950f44..53a8f80e5 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -1687,16 +1687,18 @@ box_promote(void)
 			rc = -1;
 		} else {
 promote:
-			/* We cannot possibly get here in a volatile state. */
-			assert(box_raft()->volatile_term == box_raft()->term);
+			if (try_wait)
+				raft_new_term(box_raft());
+
+			uint64_t term = box_raft()->volatile_term;
 			txn_limbo_write_promote(&txn_limbo, wait_lsn,
-						box_raft()->term);
+						term);
 			struct synchro_request req = {
 				.type = IPROTO_PROMOTE,
 				.replica_id = former_leader_id,
 				.origin_id = instance_id,
 				.lsn = wait_lsn,
-				.term = box_raft()->term,
+				.term = term,
 			};
 			txn_limbo_process(&txn_limbo, &req);
 			assert(txn_limbo_is_empty(&txn_limbo));
diff --git a/test/replication/gh-4114-local-space-replication.result b/test/replication/gh-4114-local-space-replication.result
index 9b63a4b99..676400cef 100644
--- a/test/replication/gh-4114-local-space-replication.result
+++ b/test/replication/gh-4114-local-space-replication.result
@@ -45,9 +45,8 @@ test_run:cmd('switch replica')
  | ---
  | - true
  | ...
-box.info.vclock[0]
+a = box.info.vclock[0] or 0
  | ---
- | - null
  | ...
 box.cfg{checkpoint_count=1}
  | ---
@@ -77,9 +76,9 @@ box.space.test:insert{3}
  | - [3]
  | ...
 
-box.info.vclock[0]
+box.info.vclock[0] == a + 3 or box.info.vclock[0] - a
  | ---
- | - 3
+ | - true
  | ...
 
 test_run:cmd('switch default')
diff --git a/test/replication/gh-4114-local-space-replication.test.lua b/test/replication/gh-4114-local-space-replication.test.lua
index c18fb3b10..8f787db84 100644
--- a/test/replication/gh-4114-local-space-replication.test.lua
+++ b/test/replication/gh-4114-local-space-replication.test.lua
@@ -18,7 +18,7 @@ for i = 1,10 do box.space.test:insert{i} end
 box.info.vclock[0] == a + 10 or box.info.vclock[0] - a
 
 test_run:cmd('switch replica')
-box.info.vclock[0]
+a = box.info.vclock[0] or 0
 box.cfg{checkpoint_count=1}
 box.space.test:select{}
 box.space.test:insert{1}
@@ -27,7 +27,7 @@ box.space.test:insert{2}
 box.snapshot()
 box.space.test:insert{3}
 
-box.info.vclock[0]
+box.info.vclock[0] == a + 3 or box.info.vclock[0] - a
 
 test_run:cmd('switch default')
 
diff --git a/test/replication/gh-6034-promote-bump-term.result b/test/replication/gh-6034-promote-bump-term.result
new file mode 100644
index 000000000..20e352922
--- /dev/null
+++ b/test/replication/gh-6034-promote-bump-term.result
@@ -0,0 +1,37 @@
+-- test-run result file version 2
+test_run = require('test_run').new()
+ | ---
+ | ...
+
+-- gh-6034: test that every box.ctl.promote() bumps
+-- the instance's term. Even when elections are disabled. Even for consequent
+-- promotes on the same instance.
+election_mode = box.cfg.election_mode
+ | ---
+ | ...
+box.cfg{election_mode='off'}
+ | ---
+ | ...
+
+term = box.info.election.term
+ | ---
+ | ...
+box.ctl.promote()
+ | ---
+ | ...
+assert(box.info.election.term == term + 1)
+ | ---
+ | - true
+ | ...
+box.ctl.promote()
+ | ---
+ | ...
+assert(box.info.election.term == term + 2)
+ | ---
+ | - true
+ | ...
+
+-- Cleanup.
+box.cfg{election_mode=election_mode}
+ | ---
+ | ...
diff --git a/test/replication/gh-6034-promote-bump-term.test.lua b/test/replication/gh-6034-promote-bump-term.test.lua
new file mode 100644
index 000000000..5847dbb8f
--- /dev/null
+++ b/test/replication/gh-6034-promote-bump-term.test.lua
@@ -0,0 +1,16 @@
+test_run = require('test_run').new()
+
+-- gh-6034: test that every box.ctl.promote() bumps
+-- the instance's term. Even when elections are disabled. Even for consequent
+-- promotes on the same instance.
+election_mode = box.cfg.election_mode
+box.cfg{election_mode='off'}
+
+term = box.info.election.term
+box.ctl.promote()
+assert(box.info.election.term == term + 1)
+box.ctl.promote()
+assert(box.info.election.term == term + 2)
+
+-- Cleanup.
+box.cfg{election_mode=election_mode}
diff --git a/test/replication/suite.cfg b/test/replication/suite.cfg
index b0f275526..4fc6643e4 100644
--- a/test/replication/suite.cfg
+++ b/test/replication/suite.cfg
@@ -48,6 +48,7 @@
     "gh-5613-bootstrap-prefer-booted.test.lua": {},
     "gh-6027-applier-error-show.test.lua": {},
     "gh-6032-promote-wal-write.test.lua": {},
+    "gh-6034-promote-bump-term.test.lua": {},
     "gh-6057-qsync-confirm-async-no-wal.test.lua": {},
     "gh-6094-rs-uuid-mismatch.test.lua": {},
     "gh-6127-election-join-new.test.lua": {},
-- 
2.30.1 (Apple Git-130)