fix: fix nested transaction entering in pipeline mode

If the connection is idle, it might be that we are missing results.
Receive them to align the connection state to what the transaction
object expects, otherwise the assert in _push_savepoint() will fail.

diff --git a/psycopg/psycopg/transaction.py b/psycopg/psycopg/transaction.py
index 35ef973d861093cdd540e0e1a90de2fe8924f1db..3477f8cfeb251667f9dfdaaf90f60a26cf564623 100644 (file)
--- a/psycopg/psycopg/transaction.py
+++ b/psycopg/psycopg/transaction.py
@@ -90,6 +90,16 @@ class BaseTransaction(Generic[ConnectionType]):
             raise TypeError("transaction blocks can be used only once")
         self._entered = True
 
+        # If we are in pipeline mode and connection idle, we might be in a
+        # nested statement but we haven't received yet the result to go
+        # INTRANS. This would make _push_savepoint() fail. If so, synchronize
+        # with the server.
+        if (
+            self._conn._pipeline
+            and self.pgconn.transaction_status == TransactionStatus.IDLE
+        ):
+            yield from self._conn._pipeline._sync_gen()
+
         self._push_savepoint()
         for command in self._get_enter_commands():
             yield from self._conn._exec_command(command)

diff --git a/tests/test_pipeline.py b/tests/test_pipeline.py
index ba3d3d6ef202b8b269dbc9d837401462dc9c213f..b20359f8c5c6dc385721f073a7d57d76417eb68d 100644 (file)
--- a/tests/test_pipeline.py
+++ b/tests/test_pipeline.py
@@ -398,6 +398,16 @@ def test_transaction_nested(conn):
         assert r == "inner"
 
 
+def test_transaction_nested_no_statement(conn):
+    with conn.pipeline():
+        with conn.transaction():
+            with conn.transaction():
+                cur = conn.execute("select 1")
+
+        (r,) = cur.fetchone()
+        assert r == 1
+
+
 def test_outer_transaction(conn):
     with conn.transaction():
         with conn.pipeline():

diff --git a/tests/test_pipeline_async.py b/tests/test_pipeline_async.py
index 6f774a5bdbf82e4c768dcac8d83a3a9bfe81883e..5d7e669dd3a3e11ba45173ba825d5f1a97fc2bbc 100644 (file)
--- a/tests/test_pipeline_async.py
+++ b/tests/test_pipeline_async.py
@@ -400,6 +400,16 @@ async def test_transaction_nested(aconn):
         assert r == "inner"
 
 
+async def test_transaction_nested_no_statement(aconn):
+    async with aconn.pipeline():
+        async with aconn.transaction():
+            async with aconn.transaction():
+                cur = await aconn.execute("select 1")
+
+        (r,) = await cur.fetchone()
+        assert r == 1
+
+
 async def test_outer_transaction(aconn):
     async with aconn.transaction():
         async with aconn.pipeline():