[rfc] [patch] sftp unit tests without ssh

[John A Meinel]

Robey Pointer wrote:
> 
> On 25 Jan 2006, at 10:57, John A Meinel wrote:
> 
>> Robey Pointer wrote:
>>>
>>> On 24 Jan 2006, at 12:00, John Arbash Meinel wrote:
>>>
>>>> However, after merging you I get:
>>>> ~bzr: WARNING: Exception from within unit test server thread:
>>>> <socket.error instance at 0xb6b6894c>
>>>> ~bzr: WARNING: Exception from within unit test server thread:
>>>> <socket.error instance at 0xb6b68bac>
>>>> ~bzr: WARNING: Exception from within unit test server thread:
>>>> <socket.error instance at 0xb6b6582c>
>>>>
>>>> Probably we should also us 'log_exception_quietly()' which puts a
>>>> traceback into ~/.bzr.log, which would help debug this.
>>>
>>> I see these sometimes, though I can't reproduce them right now (probably
>>> laptop slowness).  log_exception_quietly() won't help much, because the
>>> logs are erased right after each test, so you'll never see the
>>> exception. :)
>>>
>>> I think the error is just a shutdown synchronization problem: one side
>>> closing before the other is finished.  Probably the unit test's
>>> destructors abruptly closing sockets that the server thinks are still in
>>> play -- which is why the don't cause the test to fail.  Maybe we should
>>> just catch and squelch socket.errors, but I wish I could catch one in
>>> the act just to make sure.
>>
>> You could always print the traceback to sys.stdout.
>> traceback.print_exc() works just fine. Only run_bzr is setup to redirect
>> sys.stdout.
> 
> Of course, I was able to reproduce this minutes after I sent the email.
> :)  Turns out that it's just a socket.error from a failed write after
> the socket is closed, so it's harmless.  I checked in the attached patch
> to my bzr.dev.sftp branch to squelch the warning.
> 
> robey
> 
> 

Is it a time when we are trying to write to a closed socket? Like on the
client side we got an exception an exited, rather than continuing?

I'm just worried that if we catch all socket exceptions and throw them
away, we might miss future bugs.

> 
> ------------------------------------------------------------------------
> 
> === modified file 'bzrlib/transport/sftp.py'
> --- bzrlib/transport/sftp.py
> +++ bzrlib/transport/sftp.py
> @@ -896,9 +896,13 @@
>          self._socket.close()
>          try:
>              self._callback(s, self.stop_event)
> +        except socket.error:
> +            pass
>          except Exception, x:
>              # probably a failed test
>              warning('Exception from within unit test server thread: %r' % x)
> +            import traceback
> +            warning(traceback.format_exc())
>  
>      def stop(self):
>          self.stop_event.set()
> 

Why is self._callback() writing to the socket? Since we just did
_socket.close() it seems the real bug lies in something writing to the
socket.
So either we fix the callbacks, or we move self._socket.close() after
calling the callback.

John
=:->

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