[lldb] Add type hints to gdbclientutils.py and fix issues

Everything in this should be python 3.9. The docs say the minimum is 3.8
but there's existing code in this suite that needs 3.9 so I think 3.9 is
ok.

Issues:
qEcho() is passed an argument by the callers that the function didn't have
Several functions in the base class would silently do nothing if not
overriden. These now use @AbstractMethod to require overrides
sendall() had inconsistent return types between overrides

Author: dsandersllvm

lldb/packages/Python/lldbsuite/test/gdbclientutils.py

@@ -1,10 +1,12 @@
+from abc import ABC, abstractmethod
 import ctypes
 import errno
 import io
 import threading
 import socket
 import traceback
 from lldbsuite.support import seven
+from typing import Optional
 
 
 def checksum(message):
@@ -86,8 +88,8 @@ class MockGDBServerResponder:
     handles any packet not recognized in the common packet handling code.
     """
 
-    registerCount = 40
-    packetLog = None
+    registerCount: int = 40
+    packetLog: Optional[list[str]] = None
 
     class RESPONSE_DISCONNECT:
         pass
@@ -103,6 +105,7 @@ def respond(self, packet):
         Return the unframed packet data that the server should issue in response
         to the given packet received from the client.
         """
+        assert self.packetLog is not None
         self.packetLog.append(packet)
         if packet is MockGDBServer.PACKET_INTERRUPT:
             return self.interrupt()
@@ -242,7 +245,7 @@ def qProcessInfo(self):
     def qHostInfo(self):
         return "ptrsize:8;endian:little;"
 
-    def qEcho(self):
+    def qEcho(self, _: int):
         return "E04"
 
     def qQueryGDBServer(self):
@@ -263,10 +266,10 @@ def A(self, packet):
     def D(self, packet):
         return "OK"
 
-    def readRegisters(self):
+    def readRegisters(self) -> str:
         return "00000000" * self.registerCount
 
-    def readRegister(self, register):
+    def readRegister(self, register: int) -> str:
         return "00000000"
 
     def writeRegisters(self, registers_hex):
@@ -306,7 +309,8 @@ def haltReason(self):
         # SIGINT is 2, return type is 2 digit hex string
         return "S02"
 
-    def qXferRead(self, obj, annex, offset, length):
+    def qXferRead(self, obj: str, annex: str, offset: int,
+                  length: int) -> tuple[str | None, bool]:
         return None, False
 
     def _qXferResponse(self, data, has_more):
@@ -374,15 +378,17 @@ class UnexpectedPacketException(Exception):
         pass
 
 
-class ServerChannel:
+class ServerChannel(ABC):
     """
     A wrapper class for TCP or pty-based server.
     """
 
-    def get_connect_address(self):
+    @abstractmethod
+    def get_connect_address(self) -> str:
         """Get address for the client to connect to."""
 
-    def get_connect_url(self):
+    @abstractmethod
+    def get_connect_url(self) -> str:
         """Get URL suitable for process connect command."""
 
     def close_server(self):
@@ -394,10 +400,12 @@ def accept(self):
     def close_connection(self):
         """Close all resources used by the accepted connection."""
 
-    def recv(self):
+    @abstractmethod
+    def recv(self) -> bytes:
         """Receive a data packet from the connected client."""
 
-    def sendall(self, data):
+    @abstractmethod
+    def sendall(self, data: bytes) -> None:
         """Send the data to the connected client."""
 
 
@@ -428,11 +436,11 @@ def close_connection(self):
         self._connection.close()
         self._connection = None
 
-    def recv(self):
+    def recv(self) -> bytes:
         assert self._connection is not None
         return self._connection.recv(4096)
 
-    def sendall(self, data):
+    def sendall(self, data: bytes) -> None:
         assert self._connection is not None
         return self._connection.sendall(data)
 
@@ -444,21 +452,21 @@ def __init__(self):
         )[0]
         super().__init__(family, type, proto, addr)
 
-    def get_connect_address(self):
+    def get_connect_address(self) -> str:
         return "[{}]:{}".format(*self._server_socket.getsockname())
 
-    def get_connect_url(self):
+    def get_connect_url(self) -> str:
         return "connect://" + self.get_connect_address()
 
 
 class UnixServerSocket(ServerSocket):
     def __init__(self, addr):
         super().__init__(socket.AF_UNIX, socket.SOCK_STREAM, 0, addr)
 
-    def get_connect_address(self):
+    def get_connect_address(self) -> str:
         return self._server_socket.getsockname()
 
-    def get_connect_url(self):
+    def get_connect_url(self) -> str:
         return "unix-connect://" + self.get_connect_address()
 
 
@@ -472,7 +480,7 @@ def __init__(self):
         self._primary = io.FileIO(primary, "r+b")
         self._secondary = io.FileIO(secondary, "r+b")
 
-    def get_connect_address(self):
+    def get_connect_address(self) -> str:
         libc = ctypes.CDLL(None)
         libc.ptsname.argtypes = (ctypes.c_int,)
         libc.ptsname.restype = ctypes.c_char_p
@@ -485,7 +493,7 @@ def close_server(self):
         self._secondary.close()
         self._primary.close()
 
-    def recv(self):
+    def recv(self) -> bytes:
         try:
             return self._primary.read(4096)
         except OSError as e:
@@ -494,8 +502,8 @@ def recv(self):
                 return b""
             raise
 
-    def sendall(self, data):
-        return self._primary.write(data)
+    def sendall(self, data: bytes) -> None:
+        self._primary.write(data)
 
 
 class MockGDBServer:
@@ -528,18 +536,21 @@ def stop(self):
             self._thread.join()
             self._thread = None
 
-    def get_connect_address(self):
+    def get_connect_address(self) -> str:
+        assert self._socket is not None
         return self._socket.get_connect_address()
 
-    def get_connect_url(self):
+    def get_connect_url(self) -> str:
+        assert self._socket is not None
         return self._socket.get_connect_url()
 
     def run(self):
+        assert self._socket is not None
         # For testing purposes, we only need to worry about one client
         # connecting just one time.
         try:
             self._socket.accept()
-        except:
+        except Exception:
             traceback.print_exc()
             return
         self._shouldSendAck = True
@@ -554,7 +565,7 @@ def run(self):
                 self._receive(data)
         except self.TerminateConnectionException:
             pass
-        except Exception as e:
+        except Exception:
             print(
                 "An exception happened when receiving the response from the gdb server. Closing the client..."
             )
@@ -587,7 +598,9 @@ def _parsePacket(self):
         Once a complete packet is found at the front of self._receivedData,
         its data is removed form self._receivedData.
         """
+        assert self._receivedData is not None
         data = self._receivedData
+        assert self._receivedDataOffset is not None
         i = self._receivedDataOffset
         data_len = len(data)
         if data_len == 0:
@@ -640,10 +653,13 @@ def _parsePacket(self):
         self._receivedDataOffset = 0
         return packet
 
-    def _sendPacket(self, packet):
-        self._socket.sendall(seven.bitcast_to_bytes(frame_packet(packet)))
+    def _sendPacket(self, packet: str):
+        assert self._socket is not None
+        framed_packet = seven.bitcast_to_bytes(frame_packet(packet))
+        self._socket.sendall(framed_packet)
 
     def _handlePacket(self, packet):
+        assert self._socket is not None
         if packet is self.PACKET_ACK:
             # Ignore ACKs from the client. For the future, we can consider
             # adding validation code to make sure the client only sends ACKs