Fix linux failures

Author: rchiodo

src/debugpy/adapter/clients.py

@@ -6,15 +6,17 @@
 
 import atexit
 import os
-import socket
 import sys
-from typing import Any, Literal, Union, cast
+from typing import TYPE_CHECKING, Any, Literal, Union, cast
 
 import debugpy
 from debugpy import adapter, common, launcher
 from debugpy.common import json, log, messaging, sockets
 from debugpy.adapter import clients, components, launchers, servers, sessions
 
+if TYPE_CHECKING:
+    # socket can't be imported at runtime on linux, causes runtime issues.
+    import socket
 
 class Client(components.Component):
     """Handles the client side of a debug session."""
@@ -43,7 +45,7 @@ class Expectations(components.Capabilities):
             "pathFormat": json.enum("path", optional=True),  # we don't support "uri"
         }
 
-    def __init__(self, sock: Union[Literal["stdio"], socket.socket]):
+    def __init__(self, sock: "Union[Literal[\"stdio\"], socket.socket]"):
         if sock == "stdio":
             log.info("Connecting to client over stdio...", self)
             self.using_stdio = True