derivepassphrase.git

@@ -146,7 +146,28 @@ class SSHAgentClient:

         from derivepassphrase.ssh_agent import socketprovider  # noqa: PLC0415

-        if isinstance(socket, _socket.socket):

+        # On POSIX, the predominant type of communication channel is the

+        # UNIX domain socket, which in Python is represented as

+        # a `socket.socket` object.  This is (as of January 2026)

+        # unsupported on The Annoying OS: Only in Windows 10 (on some

+        # later builds at least) did Microsoft ship a partial

+        # implementation of named UNIX domain sockets in stream mode,

+        # but because of the limited scope Python does not provide

+        # bindings to this functionality.  (The Annoying OS has other

+        # predominant communication channels, but these are not

+        # represented as `socket.socket` objects.)

+        #

+        # Thus, for practical purposes, using a `socket.socket` object

+        # to interface a running SSH agent is not a valid code path on

+        # The Annoying OS.  The code path should therefore be marked as

+        # such.

+        #

+        # https://devblogs.microsoft.com/commandline/af_unix-comes-to-windows/

+        # https://github.com/microsoft/WSL/issues/4240

+        # https://github.com/python/cpython/issues/77589

+        if isinstance(

+            socket, _socket.socket

+        ):  # pragma: unless posix no cover [external]

             self._connection = socket

             # Test whether the socket is connected.

             self._connection.getpeername()

@@ -512,7 +512,9 @@ class WindowsNamedPipeHandle:

                 ctypes.cast(ctypes.byref(write_count), LPDWORD),

                 ctypes.cast(ctypes.byref(overlapped_struct), LPOVERLAPPED),

             )

-            if not success and GetLastError() == ERROR_IO_PENDING:

+            if (

+                not success and GetLastError() == ERROR_IO_PENDING

+            ):  # pragma: no cover [external]

                 success = GetOverlappedResult(

                     self.handle,

                     ctypes.cast(ctypes.byref(overlapped_struct), LPOVERLAPPED),

@@ -460,8 +460,13 @@ for key, handler in spawn_handlers.items():

 Popen = TypeVar("Popen", bound=subprocess.Popen)

+# As of v0.6, all SSH agents we interact with on The Annoying OS are

+# interfaced, not spawned.  Therefore, this context manager is unused on

+# The Annoying OS.

 @contextlib.contextmanager

-def terminate_on_exit(proc: Popen) -> Iterator[Popen]:

+def terminate_on_exit(

+    proc: Popen,

+) -> Iterator[Popen]:  # pragma: unless posix no cover [unused]

     """Terminate and wait for the subprocess upon exiting the context.

     Args: