[PATCH 2/5] txn: run on_rollback triggers on txn_abort

[Vladimir Davydov]

When a memtx transaction is aborted on yield, it isn't enough to
rollback individual statements - we must also run on_rollback triggers,
otherwise changes done to the schema by an aborted DDL transaction will
be visible to other fibers until an attempt to commit it is made.
---
 src/box/txn.c                 |  7 ++++++-
 test/box/transaction.result   | 24 ++++++++++++++++++++++++
 test/box/transaction.test.lua | 10 ++++++++++
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/box/txn.c b/src/box/txn.c
index 818f405b..5d80833a 100644
--- a/src/box/txn.c
+++ b/src/box/txn.c
@@ -346,6 +346,7 @@ txn_run_triggers(struct txn *txn, struct rlist *trigger)
 	 * Some triggers require for in_txn variable to be set so
 	 * restore it for the time triggers are in progress.
 	 */
+	struct txn *old_txn = in_txn();
 	fiber_set_txn(fiber(), txn);
 	/* Rollback triggers must not throw. */
 	if (trigger_run(trigger, txn) != 0) {
@@ -357,7 +358,7 @@ txn_run_triggers(struct txn *txn, struct rlist *trigger)
 		unreachable();
 		panic("commit/rollback trigger failed");
 	}
-	fiber_set_txn(fiber(), NULL);
+	fiber_set_txn(fiber(), old_txn);
 }
 
 /**
@@ -556,6 +557,10 @@ void
 txn_abort(struct txn *txn)
 {
 	txn_rollback_to_svp(txn, NULL);
+	if (txn->has_triggers) {
+		txn_run_triggers(txn, &txn->on_rollback);
+		txn->has_triggers = false;
+	}
 	txn->is_aborted = true;
 }
 
diff --git a/test/box/transaction.result b/test/box/transaction.result
index 9da53e5b..857314b7 100644
--- a/test/box/transaction.result
+++ b/test/box/transaction.result
@@ -698,3 +698,27 @@ box.space.memtx:drop()
 box.space.vinyl:drop()
 ---
 ...
+--
+-- Check that changes done to the schema by a DDL statement are
+-- rolled back when the transaction is aborted on fiber yield.
+--
+s = box.schema.space.create('test')
+---
+...
+box.begin() s:create_index('pk') s:insert{1}
+---
+...
+fiber.sleep(0)
+---
+...
+s.index.pk == nil
+---
+- true
+...
+box.commit() -- error
+---
+- error: Transaction has been aborted by a fiber yield
+...
+s:drop()
+---
+...
diff --git a/test/box/transaction.test.lua b/test/box/transaction.test.lua
index a6789316..8ffae2fe 100644
--- a/test/box/transaction.test.lua
+++ b/test/box/transaction.test.lua
@@ -363,3 +363,13 @@ if box.space.test then box.space.test:drop() end
 box.space.memtx:drop()
 box.space.vinyl:drop()
 
+--
+-- Check that changes done to the schema by a DDL statement are
+-- rolled back when the transaction is aborted on fiber yield.
+--
+s = box.schema.space.create('test')
+box.begin() s:create_index('pk') s:insert{1}
+fiber.sleep(0)
+s.index.pk == nil
+box.commit() -- error
+s:drop()
-- 
2.11.0