scp doesn't check the exit code of the remote command (needed for Windows)

[madscientist]

scp doesn't check the exit code of the remote scp operation.

Unfortunately the scp command that comes with Windows 10 apparently doesn't provide any error messages at all on failure: if the scp fails the ONLY way to know is to see that the remote exited with a non-zero code. Unfortunately with no messages there's no way to know why it failed, but that's a problem in the Windows10 scp program that we can't do anything about. However, we can report the exit code.

FYI, here's the interesting output of running a local scp -v -v from my GNU/Linux system to a remote Windows10 system, copying a file down from the Windows system to my local system.

First here's a successful copy for an existing file:

debug1: Sending command: scp -v -f foobar
 ...
debug2: channel_input_status_confirm: type 99 id 1
debug2: exec request accepted on channel 1
Sink: C0666 5 foobar
debug2: channel 1: rcvd ext data 36
Sending file modes: C0666 5 foobar
debug2: channel 1: written 36 to efd 7
debug2: channel 1: rcvd eof
 ...
debug1: Exit status 0

Now here's a request for a non-existent file:

debug1: Sending command: scp -v -f foobar.xx
  ...
debug2: channel_input_status_confirm: type 99 id 1
debug2: exec request accepted on channel 1
debug2: channel 1: rcvd eof
  ...
debug1: Exit status 1

[MrMino]

FTR this is also an issue with servers that don't support SCP (i.e. where the command is missing). There, the EC is 127.