From: Federico Caselli <cfederico87@gmail.com>
Date: Mon, 11 Apr 2022 21:19:16 +0000 (+0200)
Subject: Fix psycopg2 pre_ping with autocommit
X-Git-Tag: rel_2_0_0b1~352^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c154ed5e047113ce6763cc5a26741f6a5022eb1d;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

Fix psycopg2 pre_ping with autocommit

Fixed an issue what would cause autocommit mode to be reset
when using pre_ping in conjunction engine level autocommit
on the psycopg2 driver.

Fixes: #7930
Change-Id: I4cccaf1b7f8cbacd853689458080784114fcc390
---

diff --git a/doc/build/changelog/unreleased_14/7930.rst b/doc/build/changelog/unreleased_14/7930.rst
new file mode 100644
index 0000000000..bf4f9988ca
--- /dev/null
+++ b/doc/build/changelog/unreleased_14/7930.rst
@@ -0,0 +1,7 @@
+.. change::
+    :tags: bug, postgresql
+    :tickets: 7930
+
+    Fixed an issue what would cause autocommit mode to be reset
+    when using pre_ping in conjunction engine level autocommit
+    on the psycopg2 driver.
diff --git a/lib/sqlalchemy/dialects/postgresql/_psycopg_common.py b/lib/sqlalchemy/dialects/postgresql/_psycopg_common.py
index 7f936fefbf..e7d5e77c39 100644
--- a/lib/sqlalchemy/dialects/postgresql/_psycopg_common.py
+++ b/lib/sqlalchemy/dialects/postgresql/_psycopg_common.py
@@ -170,15 +170,17 @@ class _PGDialect_common_psycopg(PGDialect):
 
     def do_ping(self, dbapi_connection):
         cursor = None
+        before_autocommit = dbapi_connection.autocommit
         try:
-            self._do_autocommit(dbapi_connection, True)
+            if not before_autocommit:
+                self._do_autocommit(dbapi_connection, True)
             cursor = dbapi_connection.cursor()
             try:
                 cursor.execute(self._dialect_specific_select_one)
             finally:
                 cursor.close()
-                if not dbapi_connection.closed:
-                    self._do_autocommit(dbapi_connection, False)
+                if not before_autocommit and not dbapi_connection.closed:
+                    self._do_autocommit(dbapi_connection, before_autocommit)
         except self.dbapi.Error as err:
             if self.is_disconnect(err, dbapi_connection, cursor):
                 return False
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg.py b/lib/sqlalchemy/dialects/postgresql/psycopg.py
index 9207221df6..b811d1cabb 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg.py
@@ -385,12 +385,14 @@ class PGDialect_psycopg(_PGDialect_common_psycopg):
             != self._psycopg_TransactionStatus.IDLE
         ):
             dbapi_conn.rollback()
-        before = dbapi_conn.autocommit
+        before_autocommit = dbapi_conn.autocommit
         try:
-            self._do_autocommit(dbapi_conn, True)
+            if not before_autocommit:
+                self._do_autocommit(dbapi_conn, True)
             dbapi_conn.execute(command)
         finally:
-            self._do_autocommit(dbapi_conn, before)
+            if not before_autocommit:
+                self._do_autocommit(dbapi_conn, before_autocommit)
 
     def do_rollback_twophase(
         self, connection, xid, is_prepared=True, recover=False
diff --git a/test/dialect/postgresql/test_dialect.py b/test/dialect/postgresql/test_dialect.py
index fb3a522fc1..0093eb5ba7 100644
--- a/test/dialect/postgresql/test_dialect.py
+++ b/test/dialect/postgresql/test_dialect.py
@@ -1068,6 +1068,23 @@ class MiscBackendTest(
                 dbapi_conn.rollback()
             eq_(val, "off")
 
+    @testing.combinations((True,), (False,), argnames="autocommit")
+    def test_autocommit_pre_ping(self, testing_engine, autocommit):
+        engine = testing_engine(
+            options={
+                "isolation_level": "AUTOCOMMIT"
+                if autocommit
+                else "SERIALIZABLE",
+                "pool_pre_ping": True,
+            }
+        )
+        for i in range(4):
+            with engine.connect() as conn:
+                conn.execute(text("select 1")).scalar()
+
+                dbapi_conn = conn.connection.dbapi_connection
+                eq_(dbapi_conn.autocommit, autocommit)
+
     def test_deferrable_flag_engine(self):
         engine = engines.testing_engine(
             options={