[tahoe-dev] [tahoe-lafs] #1190: we can end up importing the wrong version of a dependency even though the right one is "already the active version in easy-install.pth"

[tahoe-lafs]

#1190: we can end up importing the wrong version of a dependency even though the
right one is "already the active version in easy-install.pth"
----------------------------+-----------------------------------------------
     Reporter:  davidsarah  |       Owner:  zooko                                
         Type:  defect      |      Status:  new                                  
     Priority:  major       |   Milestone:  1.8.1                                
    Component:  packaging   |     Version:  1.8β                                 
   Resolution:              |    Keywords:  setuptools test forward-compatibility
Launchpad Bug:              |  
----------------------------+-----------------------------------------------
Changes (by davidsarah):

  * keywords:  setuptools test review-needed => setuptools test forward-
               compatibility
  * owner:  davidsarah => zooko


Comment:

 [4764/ticket1190] and [4766/ticket1190] look ok, or at least worth trying.

 [4765/ticket1190] adds a {{{__requires__}}} line to newly generated
 {{{.tac}}} files. This is liable to cause the same kind of forward-
 compatibility problem we had trying to change the {{{appname}}} in #1159
 -- i.e. when we change the requirements, existing {{{.tac}}} files will
 still reflect the requirements at the time they were generated.

 (This will cause even more subtle problems than the {{{appname}}} change,
 because the effect will be to allow earlier versions of dependencies than
 intended, and so regress bugs we thought we'd fixed, rather than always
 failing when an old {{{.tac}}} is used.)

 I'm more and more convinced that {{{.tac}}} files are more trouble than
 they're worth and that we should stop using them (see
 ticket:1159#comment:10). Node directories should contain only data, not
 code.

-- 
Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/1190#comment:5>
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