[tahoe-lafs-trac-stream] [Tahoe-LAFS] #2468: updates to indirect dependencies cause build failures

[Tahoe-LAFS]

#2468: updates to indirect dependencies cause build failures
----------------------------------+---------------------------
 Reporter:  daira                 |          Owner:  daira
     Type:  defect                |         Status:  new
 Priority:  normal                |      Milestone:  undecided
Component:  packaging             |        Version:  1.10.1
 Keywords:  packaging setuptools  |  Launchpad Bug:
----------------------------------+---------------------------
 Consider the case where Tahoe initially depends on foo >= X.0, and foo X.0
 depends on bar Y.0. Then foo X.1 is released which depends on bar Y.1.
 (This is a common situation, especially when foo and bar have overlapping
 development teams.)

 Suppose that a particular machine has bar Y.0 installed globally. What is
 supposed to happen is that, in the case where a Tahoe build on that
 machine downloads foo X.1, it also downloads bar Y.1 and builds it under
 `support/`.

 However, that doesn't happen. Instead we get an error:
 {{{
 error: Installed distribution bar Y.0 conflicts with requirement bar>=Y.1
 }}}

 For a concrete example, see [https://tahoe-lafs.org/buildbot-tahoe-
 lafs/builders/memcheck-32/builds/96/steps/compile/logs/stdio]:
 {{{
 Need pyasn1-modules>=0.0.5
 Searching for pyasn1-modules>=0.0.5
 Reading http://pypi.python.org/simple/pyasn1-modules/
 Best match: pyasn1-modules 0.0.6
 Downloading
 https://pypi.python.org/packages/2.7/p/pyasn1-modules/pyasn1_modules-0.0.6-py2.7.egg#md5=c5d2ed9c850538f57effed3c7b74bbfb
 Processing pyasn1_modules-0.0.6-py2.7.egg
 creating /home/bb-tahoe/bb-tahoe/memcheck-32/build/support/lib/python2.7
 /site-packages/pyasn1_modules-0.0.6-py2.7.egg
 Extracting pyasn1_modules-0.0.6-py2.7.egg to /home/bb-tahoe/bb-
 tahoe/memcheck-32/build/support/lib/python2.7/site-packages
 Adding pyasn1-modules 0.0.6 to easy-install.pth file

 Installed /home/bb-tahoe/bb-tahoe/memcheck-32/build/support/lib/python2.7
 /site-packages/pyasn1_modules-0.0.6-py2.7.egg
   found pyasn1-modules 0.0.6 (/home/bb-tahoe/bb-
 tahoe/memcheck-32/build/support/lib/python2.7/site-
 packages/pyasn1_modules-0.0.6-py2.7.egg)
   adding subdependency pyasn1>=0.1.8

 Need pyasn1>=0.1.4
   found pyasn1 0.1.7 (/usr/lib/python2.7/dist-packages)
   no subdependencies to add

 [...]
 error: Installed distribution pyasn1 0.1.7 conflicts with requirement
 pyasn1>=0.1.8
 }}}

 setuptools delenda est.

--
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2468>
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