[tahoe-lafs-trac-stream] [Tahoe-LAFS] #2221: allow use of pyOpenSSL 0.14

[Tahoe-LAFS]

#2221: allow use of pyOpenSSL 0.14
-------------------------+-------------------------------------------------
     Reporter:  daira    |      Owner:
         Type:  defect   |     Status:  new
     Priority:  major    |  Milestone:  soon
    Component:           |    Version:  1.10.0
  packaging              |   Keywords:  packaging setuptools pyopenssl
   Resolution:           |  cryptography six cffi pycparser
Launchpad Bug:           |
-------------------------+-------------------------------------------------

Old description:

> For Tahoe-LAFS 1.11 we decided to fix the pyOpenSSL version requirement
> to == 0.13, in order to mitigate problems with building the
> `cryptography` library that is a dependency of pyOpenSSL >= 0.14 (see
> #2193 for details).
>
> This ticket is for a longer-term solution to allow use of pyOpenSSL >=
> 0.14 without causing build/install regressions (such as #2217, or the
> requirement to manually install `libffi` on non-Windows platforms).

New description:

 For Tahoe-LAFS 1.11 we decided to fix the pyOpenSSL version requirement to
 == 0.13 [not quite; see comment:4 below], in order to mitigate problems
 with building the `cryptography` library that is a dependency of pyOpenSSL
 >= 0.14 (see #2193 for details).

 This ticket is for a longer-term solution to allow use of pyOpenSSL >=
 0.14 without causing build/install regressions (such as #2217, or the
 requirement to manually install `libffi` on some platforms).

--

Comment (by daira):

 The solution we eventually arrived at for 1.11 (for all platforms) was to
 attempt to import the OpenSSL module at build time and check its version;
 if 0.14 or above is already installed then we allow it, otherwise we use
 0.13 or 0.13.1.

 This is not entirely satisfactory; it's complicated and means that we
 don't get pyOpenSSL security fixes unless 0.14+ is installed manually.

--
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2221#comment:4>
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