[tahoe-lafs-trac-stream] [Tahoe-LAFS] #2555: publish-and-subscribe to change events on mutables

[Tahoe-LAFS]

#2555: publish-and-subscribe to change events on mutables
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     Reporter:  zooko    |      Owner:  daira
         Type:  defect   |     Status:  new
     Priority:  normal   |  Milestone:  undecided
    Component:  unknown  |    Version:  1.10.1
   Resolution:           |   Keywords:
Launchpad Bug:           |
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Comment (by zooko):

 Passing the `previous_watcher` to the storage server is just a way to let
 the storage server free up resources by ceasing to send notifications to
 that old one. The client does *not* rely on the storage server's behavior
 with regard to that! The client implements a purely client-side ordering
 guarantee in which it synchronously disables the old watcher (the old
 watcher is effectively a revocable forwarder) before it sends this request
 to the server and gives the server access to the new watcher.

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Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2555#comment:1>
Tahoe-LAFS <https://Tahoe-LAFS.org>
secure decentralized storage