[tor-bugs] #11558 [Obfsproxy]: obfsproxy breaks with old versions of twisted

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#11558: obfsproxy breaks with old versions of twisted
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     Reporter:  yawning    |      Owner:  asn
         Type:  defect     |     Status:  needs_review
     Priority:  normal     |  Milestone:
    Component:  Obfsproxy  |    Version:
   Resolution:             |   Keywords:  debian, twisted, ancient
Actual Points:             |  Parent ID:
       Points:             |
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Comment (by asn):

 Please see my branch `bug11558_optional_deps` for an alternative approach.

 The idea was to treat txsocksx as an optional dependency, that is imported
 only when proxies are used.
 Also, if proxies are used but there is no txsocksx or twisted is outdated,
 then we throw an exception (or a `PROXY-ERROR` message).

 I wanted to try this logic, because I'm not sure if kludgy code to make us
 compatible with ancient versions of twisted/zope is going to end well (for
 example, as Yawning said, his new patch still doesn't work in my Debian
 oldstable). Also, I don't like code in `__init__.py`.

 Also, it's nice to not add new dependencies (since server-side obfsproxy
 will never need txsocksx anyway).

 My branch is not ready (I still need to switch txsocksx to be an optional
 dependency), and I'm not sure if I actually like this approach.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/11558#comment:4>
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