create undefined singleton

truenas_api_client/__init__.py

@@ -58,7 +58,7 @@
     CollectionUpdateParams, ErrorExtra, ErrorObj, JobFields, JSONRPCError, JSONRPCMessage, TruenasError,
     TruenasTraceback
 )
-from .utils import MIDDLEWARE_RUN_DIR, ProgressBar, undefined
+from .utils import MIDDLEWARE_RUN_DIR, ProgressBar, undefined, UndefinedType
 try:
     from libzfs import Error as ZFSError
 except ImportError:
@@ -458,7 +458,7 @@ class Client:
 
     """
     def __init__(self, uri: str | None=None, reserved_ports=False, py_exceptions=False, log_py_exceptions=False,
-                 call_timeout: float=undefined, verify_ssl=True):
+                 call_timeout: float | UndefinedType=undefined, verify_ssl=True):
         """Initialize a `Client`.
 
         Args:
@@ -726,7 +726,7 @@ def _jobs_subscribe(self):
 
     def call(self, method: str, *params, background=False, callback: _JobCallback | None=None,
              job: Literal['RETURN'] | bool=False, register_call: bool | None=None,
-             timeout: float=undefined) -> Any:
+             timeout: float | UndefinedType=undefined) -> Any:
         """The primary way to send call requests to the API.
 
         Send a JSON-RPC v2.0 Request to the server.
@@ -781,7 +781,7 @@ def call(self, method: str, *params, background=False, callback: _JobCallback |
                 self._unregister_call(c)
 
     def wait(self, c: Call, *, callback: _JobCallback | None=None, job: Literal['RETURN'] | bool=False,
-             timeout: float=undefined) -> Any:
+             timeout: float | UndefinedType=undefined) -> Any:
         """Wait for an API call to return and return its result.
 
         Args:
@@ -804,7 +804,7 @@ def wait(self, c: Call, *, callback: _JobCallback | None=None, job: Literal['RET
             timeout = self._call_timeout
 
         try:
-            if not c.returned.wait(timeout):
+            if not c.returned.wait(timeout):  # type: ignore
                 raise CallTimeout()
 
             if c.error:

truenas_api_client/utils.py

@@ -10,12 +10,18 @@
 """
 import sys
 
-from typing import Any, TextIO, Mapping
+from typing import Any, final, TextIO, Mapping
 
 
 MIDDLEWARE_RUN_DIR = '/var/run/middleware'
-undefined = -1
 
+@final
+class UndefinedType:
+    def __new__(cls):
+        if not hasattr(cls, '_instance'):
+            cls._instance = super().__new__(cls)
+        return cls._instance
+undefined = UndefinedType()
 
 class Struct:
     """Simpler wrapper to access using object attributes instead of keys.