[libvirt] [PATCH 3/3] libvirtaio: cache the list of callbacks when calling

Wojtek Porczyk woju at invisiblethingslab.com
Thu Aug 31 19:40:38 UTC 2017

When the callback causes something that results in changes wrt
registered handles, python aborts iteration.

Relevant error message:

    Exception in callback None()
    handle: <Handle cancelled>
    Traceback (most recent call last):
      File "/usr/lib64/python3.5/asyncio/events.py", line 126, in _run
      File "/usr/lib64/python3.5/site-packages/libvirtaio.py", line 99, in _handle
        for callback in self.callbacks.values():
    RuntimeError: dictionary changed size during iteration

Signed-off-by: Wojtek Porczyk <woju at invisiblethingslab.com>
 libvirtaio.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libvirtaio.py b/libvirtaio.py
index d161cd1..46923d8 100644
--- a/libvirtaio.py
+++ b/libvirtaio.py
@@ -96,7 +96,7 @@ class Descriptor(object):
         :param int event: The event (from libvirt's constants) being dispatched
-        for callback in self.callbacks.values():
+        for callback in list(self.callbacks.values()):
             if callback.event is not None and callback.event & event:
                 callback.cb(callback.iden, self.fd, event, callback.opaque)
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