From 0b1e5c5457e6f0ea1fd60c11b7a669d494646eed Mon Sep 17 00:00:00 2001
From: ODD2 <vhanxtreme@gmail.com>
Date: Sun, 15 Jan 2023 12:59:07 +0000
Subject: [PATCH 1/2] modified error handling for 'Lost connection to MySQL
 server during query' exception occuredwhile starting a transaciton in nested
 transactions.

---
 databases/core.py | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/databases/core.py b/databases/core.py
index 8394ab5c..39dffa65 100644
--- a/databases/core.py
+++ b/databases/core.py
@@ -13,6 +13,8 @@
 from databases.importer import import_from_string
 from databases.interfaces import DatabaseBackend, Record
 
+from pymysql.err import OperationalError
+
 try:  # pragma: no cover
     import click
 
@@ -362,7 +364,11 @@ async def __aexit__(
         Called when exiting `async with database.transaction()`
         """
         if exc_type is not None or self._force_rollback:
-            await self.rollback()
+            if exc_type == OperationalError and exc_value.args[0] == 2013:
+                await self.rollback(skip=True)
+                raise exc_value
+            else:
+                await self.rollback()
         else:
             await self.commit()
 
@@ -391,10 +397,15 @@ async def start(self) -> "Transaction":
         async with self._connection._transaction_lock:
             is_root = not self._connection._transaction_stack
             await self._connection.__aenter__()
-            await self._transaction.start(
-                is_root=is_root, extra_options=self._extra_options
-            )
-            self._connection._transaction_stack.append(self)
+            try:
+                await self._transaction.start(
+                    is_root=is_root, extra_options=self._extra_options
+                )
+            except OperationalError as e:
+                await self._connection.__aexit__()
+                raise e
+            else:
+                self._connection._transaction_stack.append(self)
         return self
 
     async def commit(self) -> None:
@@ -404,11 +415,12 @@ async def commit(self) -> None:
             await self._transaction.commit()
             await self._connection.__aexit__()
 
-    async def rollback(self) -> None:
+    async def rollback(self,skip=False) -> None:
         async with self._connection._transaction_lock:
             assert self._connection._transaction_stack[-1] is self
             self._connection._transaction_stack.pop()
-            await self._transaction.rollback()
+            if(not skip):
+                await self._transaction.rollback()
             await self._connection.__aexit__()
 
 

From 3292c2f7923b1e526bfdf5c570328929fba344f2 Mon Sep 17 00:00:00 2001
From: OD <vhanxtreme@gmail.com>
Date: Mon, 17 Apr 2023 12:41:39 +0800
Subject: [PATCH 2/2] make the code concise

---
 databases/core.py | 31 ++++++++++++++++---------------
 requirements.txt  |  2 ++
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/databases/core.py b/databases/core.py
index 39dffa65..981e3c47 100644
--- a/databases/core.py
+++ b/databases/core.py
@@ -7,14 +7,13 @@
 from types import TracebackType
 from urllib.parse import SplitResult, parse_qsl, unquote, urlsplit
 
+from pymysql.err import OperationalError
 from sqlalchemy import text
 from sqlalchemy.sql import ClauseElement
 
 from databases.importer import import_from_string
 from databases.interfaces import DatabaseBackend, Record
 
-from pymysql.err import OperationalError
-
 try:  # pragma: no cover
     import click
 
@@ -364,11 +363,7 @@ async def __aexit__(
         Called when exiting `async with database.transaction()`
         """
         if exc_type is not None or self._force_rollback:
-            if exc_type == OperationalError and exc_value.args[0] == 2013:
-                await self.rollback(skip=True)
-                raise exc_value
-            else:
-                await self.rollback()
+            await self.rollback()
         else:
             await self.commit()
 
@@ -401,27 +396,33 @@ async def start(self) -> "Transaction":
                 await self._transaction.start(
                     is_root=is_root, extra_options=self._extra_options
                 )
-            except OperationalError as e:
+                self._connection._transaction_stack.append(self)
+            except Exception as e:
                 await self._connection.__aexit__()
                 raise e
-            else:
-                self._connection._transaction_stack.append(self)
         return self
 
     async def commit(self) -> None:
         async with self._connection._transaction_lock:
             assert self._connection._transaction_stack[-1] is self
             self._connection._transaction_stack.pop()
-            await self._transaction.commit()
-            await self._connection.__aexit__()
+            try:
+                await self._transaction.commit()
+            except Exception as e:
+                raise e
+            finally:
+                await self._connection.__aexit__()
 
-    async def rollback(self,skip=False) -> None:
+    async def rollback(self) -> None:
         async with self._connection._transaction_lock:
             assert self._connection._transaction_stack[-1] is self
             self._connection._transaction_stack.pop()
-            if(not skip):
+            try:
                 await self._transaction.rollback()
-            await self._connection.__aexit__()
+            except Exception as e:
+                raise e
+            finally:
+                await self._connection.__aexit__()
 
 
 class _EmptyNetloc(str):
diff --git a/requirements.txt b/requirements.txt
index 0699d3cc..1394fcc8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -20,6 +20,7 @@ pytest==7.1.2
 pytest-cov==3.0.0
 starlette==0.20.4
 requests==2.28.1
+types-PyMySQL==1.0.19.1
 
 # Documentation
 mkdocs==1.3.1
@@ -29,3 +30,4 @@ mkautodoc==0.1.0
 # Packaging
 twine==4.0.1
 wheel==0.38.1
+