From 63004c185c5fb37b14e630a9d8e6fa241e172567 Mon Sep 17 00:00:00 2001
From: Jesse Whitehouse <jesse@whitehouse.dev>
Date: Mon, 28 Oct 2024 19:03:33 -0500
Subject: [PATCH 1/2] Implement a DefaultNone so that a log message can be
 emitted if the user passes an access_token which evaluates to None

---
 src/databricks/sql/__init__.py | 19 +++++++++++++++++--
 src/databricks/sql/client.py   | 12 +++++++++---
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/src/databricks/sql/__init__.py b/src/databricks/sql/__init__.py
index 42167b00..3913f490 100644
--- a/src/databricks/sql/__init__.py
+++ b/src/databricks/sql/__init__.py
@@ -10,7 +10,7 @@
 
 import re
 
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional, Union
 
 if TYPE_CHECKING:
     # Use this import purely for type annotations, a la https://mypy.readthedocs.io/en/latest/runtime_troubles.html#import-cycles
@@ -83,8 +83,23 @@ def DateFromTicks(ticks):
 def TimestampFromTicks(ticks):
     return Timestamp(*time.localtime(ticks)[:6])
 
+def singleton(class_):
+    instances = {}
+    def getinstance(*args, **kwargs):
+        if class_ not in instances:
+            instances[class_] = class_(*args, **kwargs)
+        return instances[class_]
+    return getinstance
 
-def connect(server_hostname, http_path, access_token=None, **kwargs) -> "Connection":
+@singleton
+class DefaultNone(object):
+    """Used to represent a default value of None so that this code can distinguish between
+    the user passing None versus a default value of None being used.
+    """
+    pass
+
+
+def connect(server_hostname, http_path, access_token: Optional[Union[str, DefaultNone]]=DefaultNone, **kwargs) -> "Connection":
     from .client import Connection
 
     return Connection(server_hostname, http_path, access_token, **kwargs)
diff --git a/src/databricks/sql/client.py b/src/databricks/sql/client.py
index 4e0ab941..c89058fd 100755
--- a/src/databricks/sql/client.py
+++ b/src/databricks/sql/client.py
@@ -12,7 +12,7 @@
 import decimal
 from uuid import UUID
 
-from databricks.sql import __version__
+from databricks.sql import __version__, DefaultNone
 from databricks.sql import *
 from databricks.sql.exc import (
     OperationalError,
@@ -63,7 +63,7 @@ def __init__(
         self,
         server_hostname: str,
         http_path: str,
-        access_token: Optional[str] = None,
+        access_token: Optional[Union[str, DefaultNone]] = None,
         http_headers: Optional[List[Tuple[str, str]]] = None,
         session_configuration: Optional[Dict[str, Any]] = None,
         catalog: Optional[str] = None,
@@ -204,7 +204,13 @@ def read(self) -> Optional[OAuthToken]:
         # use_cloud_fetch
         # Enable use of cloud fetch to extract large query results in parallel via cloud storage
 
-        if access_token:
+        if access_token is DefaultNone:
+            access_token = None
+        elif access_token is None:
+            logger.info(
+                "Connection access_token was passed a None value. U2M OAuth will be attempted"
+                )
+        else:
             access_token_kv = {"access_token": access_token}
             kwargs = {**kwargs, **access_token_kv}
 

From d10270af96c25c7825e5b5e15431e87b26c424b6 Mon Sep 17 00:00:00 2001
From: Jesse Whitehouse <jesse@whitehouse.dev>
Date: Mon, 28 Oct 2024 19:16:43 -0500
Subject: [PATCH 2/2] Black the files

---
 src/databricks/sql/__init__.py | 12 +++++++++++-
 src/databricks/sql/client.py   |  2 +-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/databricks/sql/__init__.py b/src/databricks/sql/__init__.py
index 3913f490..6387fff8 100644
--- a/src/databricks/sql/__init__.py
+++ b/src/databricks/sql/__init__.py
@@ -83,23 +83,33 @@ def DateFromTicks(ticks):
 def TimestampFromTicks(ticks):
     return Timestamp(*time.localtime(ticks)[:6])
 
+
 def singleton(class_):
     instances = {}
+
     def getinstance(*args, **kwargs):
         if class_ not in instances:
             instances[class_] = class_(*args, **kwargs)
         return instances[class_]
+
     return getinstance
 
+
 @singleton
 class DefaultNone(object):
     """Used to represent a default value of None so that this code can distinguish between
     the user passing None versus a default value of None being used.
     """
+
     pass
 
 
-def connect(server_hostname, http_path, access_token: Optional[Union[str, DefaultNone]]=DefaultNone, **kwargs) -> "Connection":
+def connect(
+    server_hostname,
+    http_path,
+    access_token: Optional[Union[str, DefaultNone]] = DefaultNone,
+    **kwargs
+) -> "Connection":
     from .client import Connection
 
     return Connection(server_hostname, http_path, access_token, **kwargs)
diff --git a/src/databricks/sql/client.py b/src/databricks/sql/client.py
index c89058fd..2b83465f 100755
--- a/src/databricks/sql/client.py
+++ b/src/databricks/sql/client.py
@@ -209,7 +209,7 @@ def read(self) -> Optional[OAuthToken]:
         elif access_token is None:
             logger.info(
                 "Connection access_token was passed a None value. U2M OAuth will be attempted"
-                )
+            )
         else:
             access_token_kv = {"access_token": access_token}
             kwargs = {**kwargs, **access_token_kv}