TypeError in CopiedFailure .parents serialization

[Zooko]

I'm sure that I'm doing something wrong in my use of foolscap, but maybe it shouldn't do this:

local#1990 20:44:28.717: response from peer iwlrbdlr: alreadygot=(), allocated=(9,)
local#1991 20:44:28.717: peer selection successful for <Tahoe2PeerSelector for upload smt5x>: placed all 10 shares, sent 10 queries to 5 peers, 10 queries placed some shares, 0 pla
ced none, got 0 errors
local#1992 20:44:28.717: _send_shares, used_peers is set([<PeerTracker for peer a2niqogj and SI smt5x>, <PeerTracker for peer z3g3meyl and SI smt5x>, <PeerTracker for peer ncieuno4
 and SI smt5x>, <PeerTracker for peer bduf2tsg and SI smt5x>, <PeerTracker for peer iwlrbdlr and SI smt5x>])
local#1993 20:44:28.717: <Encoder for smt5x> starting
local#1994 20:44:28.733: starting shareholders
local#1995 20:44:28.937: an inbound callRemote that we [ncie] executed (on behalf of someone else, TubID ncie) failed
local#1996 20:44:28.937:  reqID=5, rref=<BucketWriter C:\playground\allmydata\tahoe\trunk\_trial_temp\allmydata.test.test_repairer\Verifier\test_verify_no_problem\zzyjl8\temp\clien
t0\storage\shares\sm\smt5xifqfpy6xecdu7d3q7vuqu\2>, methname=RIBucketWriter.write
local#1997 20:44:28.937:  args=[0, '\x00\x00\x00\x01\x00\x00\x00\x04\x00\x00\x00\x13\x00\x00\x00$\x00\x00\x007\x00\x00\x02\x17\x00\x00\x03\xf7\x00\x00\x05\xd7\x00\x00\x06\x81']
local#1998 20:44:28.937:  kwargs={}
local#2000 20:44:29.015: 
 FAILURE:
 [CopiedFailure instance: Traceback from remote host -- Traceback (most recent call last):
   File "build\bdist.win32\egg\foolscap\eventual.py", line 26, in _turn
     cb(*args, **kwargs)
   File "build\bdist.win32\egg\foolscap\broker.py", line 538, in doNextCall
     d.addErrback(self.callFailed, delivery.reqID, delivery)
   File "c:\python25\lib\site-packages\twisted-8.1.0-py2.5-win32.egg\twisted\internet\defer.py", line 204, in addErrback
     errbackKeywords=kw)
   File "c:\python25\lib\site-packages\twisted-8.1.0-py2.5-win32.egg\twisted\internet\defer.py", line 186, in addCallbacks
     self._runCallbacks()
 --- <exception caught here> ---
   File "c:\python25\lib\site-packages\twisted-8.1.0-py2.5-win32.egg\twisted\internet\defer.py", line 328, in _runCallbacks
     self.result = callback(self.result, *args, **kw)
   File "build\bdist.win32\egg\foolscap\broker.py", line 610, in callFailed
     delivery.logFailure(f)
   File "build\bdist.win32\egg\foolscap\call.py", line 211, in logFailure
     level=log.NOISY, parent=lp)
   File "build\bdist.win32\egg\foolscap\logging\log.py", line 196, in msg
     
   File "build\bdist.win32\egg\foolscap\call.py", line 818, in getStateToCopy
     parents[i] = truncate(value, 200)
   File "build\bdist.win32\egg\foolscap\call.py", line 747, in truncate
     if s and len(s) > limit:
 exceptions.TypeError: object of type 'type' has no len()
 ]

[Brian Warner]

Do you remember how you triggered this? It looks like you created a Failure around something that wasn't an Exception, like Failure("bare string") or Failure(42). Twisted should have stringified anything else. I can't seem to create a Failure like this on my own: the Failure constructor emits a warning and wraps my value with a DefaultException when I try to use a bare string or a number.

We could always stringify the values locally, but it'd be nice to get a test case for this in place. Let me know if you can remember how to reproduce it.