[haskell-platform] #28: Always create uninstaller

[haskell-platform]

#28: Always create uninstaller
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 Reporter:  jgbailey at gmail.com  |        Owner:  refold
     Type:  enhancement         |       Status:  new   
 Priority:  minor               |    Milestone:        
Component:  Windows installer   |   Resolution:        
 Keywords:                      |  
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Comment (by anonymous):

 > Presumably the "Just unpack the files" option doesn't want to create an
 uninstaller.

 Even unpacking files has to be undoable (though it is easy enough if all
 files are under a common root). There might be an issue in whether or not
 to register the uninstaller in the registry if the user has asked for an
 installation mode that doesn't affect the registry in any way, but this
 could be resolved (by documenting what is going on, so users know what -if
 anything- that choice is meant to accomplish, by simply creating an
 uninstaller without registering it, or by not creating an uninstaller if
 all that happens is that all files are unpacked under a common root).

 As I understand the bug report, it says two things: (a) options offered
 aren't documented well enough for users to make informed choices and (b)
 an uninstaller is just the inverse of the installer, so once you've made
 your choices for the installer (eg, no meddling with registry or
 environment variables), you shouldn't have to make any additional choices
 for the uninstaller. Solving (a) would make it obvious that there is no
 unambiguous default for (b): "You've chosen unpack only. That means that
 no uninstaller will be registered, you can uninstall by simply removing
 <directory>.". This violates the expectation that installers should
 register uninstallers, but then the software won't be "installed", just
 unpacked, in that mode, so it might be fine, if explained.

 >As I understand it, that option is supposed to be the moral equivalent of
 unpacking a .zip file. The "Just unpack the files" option is there due to
 popular demand from users who do not trust installers. Arguably we could
 move that option out and literally provide a .zip version and thus
 simplify the installer.

 Providing a .zip might be useful, but that *must not* remove the "unpack
 only" option from the installer. In this particular round, one of the
 issues that surfaced after release was that the installer uses a script
 function to modify PATH that just happens to misbehave if the PATH is long
 enough. If the uninstaller works as it should, users affected by this
 should be able to restore their system by running the uninstaller, then be
 able to use the installer in "unpack only" mode, without having to fetch
 another 50 megabyte copy of the same files.

 As nearly every Haskell installer before, this one has given further
 reason not to trust Haskell installers (mostly just too many variations of
 windows configurations, too many things that can go wrong, for any
 volunteer effort to avoid all traps in the first attempt; plus some
 inertia against following suggestions from experience in the face of self-
 imposed deadlines), so please do not remove the failsafes!-)

-- 
Ticket URL: <http://trac.haskell.org/haskell-platform/ticket/28#comment:2>
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