exception: "ConnectionDone instance has no attribute 'getTraceback'"

[Brian Warner]

Sigh. The problem that broke 0.2.0 (discovered mere minutes after its release) is still present in 0.2.1. One of the changes in 0.2.0 was to give more information to pending remote method calls which fail because the connection is lost: code was added to hand a relevant Failure object to these calls so their errbacks would see ConnectionDone? or ConnectionClosed? with a message like "duplicate connection closed by remote end" rather than something more generic.

The bug is that connectionList is specified to take a Failure instance, but in certain circumstances a bare Exception is passed in instead. When a bare exception appears as the argument to errback(), the code which attempts to extract a stack trace from the exception fails (that's what Failures are for). I fixed some of these to release 0.2.1; apparently I didn't fix all of them.

The symptom is an exception that looks like the following:

        --- <exception caught here> ---
          File "/usr/lib/python2.4/site-packages/foolscap/eventual.py", line 26, in _turn
            cb(*args, **kwargs)
          File "/usr/lib/python2.4/site-packages/foolscap/call.py", line 77, in fail
            stack = why.getTraceback()
        exceptions.AttributeError: ConnectionDone instance has no attribute 'getTraceback'

[Brian Warner]

Sometimes the exception looks like this instead:

exceptions.AttributeError: 'ConnectionDone' object has no attribute 'getTraceback'

I found at least one problem, which would only be triggered on the slave-side of a connection. In addition, the problem only surfaces if logRemoteFailures is turned on, since that's the place where we try to extract the traceback so we can dump it to the logs. This combination probably explains why it wasn't caught by the unit tests, and why it only happens intermittently elsewhere.

[Brian Warner]

.. and in looking more closely, it appears that I'm calling loseConnection() with non-Failures all over the place.

[Brian Warner]

This ought to be fixed by the new 0.2.2 release.