On Fri, 24 Sep 2004, Karl M wrote: > > From: Igor Pechtchanski Reply-To: [EMAIL PROTECTED] > > To: Max Bowsher > > CC: [EMAIL PROTECTED]
<http://cygwin.com/acronyms/#PCYMTNQREAIYR>, now with more reasons. > > Subject: Re: Is setup.exe _supposed_ to delete the cygwin dll before > > attempting to run shell scripts? > > Date: Fri, 24 Sep 2004 15:30:44 -0400 (EDT) > > > > On Fri, 24 Sep 2004, Max Bowsher wrote: > > > > > Igor Pechtchanski wrote: > > > > This is more likely to be the culprit -- postinstall scripts are > > > > run after all the package files were installed. Unfortunately, > > > > preremove script dependencies aren't easily computed from regular > > > > package dependencies -- this has been discussed on cygwin-apps > > > > some time ago. > > > > > > Couldn't this be trivially solved by running all preremove scripts > > > in a batch, before actually beginning to delete files? > > > > > > Any flaw to that reasoning? > > > > It'll work for simple programs, but not for packages where preremove > > scripts erase files that are needed to run some programs from that > > package. One example (not necessarily a perfect one) that comes to mind > > right away is the base-files package, where the preremove script will > > currently erase /etc/profile (so any script executing "bash -l" will not > > get the expected results). I'm sure there are better examples... > > > > FWIW, this is probably somewhat similar to the issue of circular > > dependencies of postinstall scripts -- there is no good general solution > > if we assume monolithic scripts. > > Igor > > > > > I guess I should now go and see how hard that would be to make happen... > > > Max. > > Would it be easier to delay the deletion of the files. What I mean is in > the preremove scripts, append the files to a list of "files to be > deleted" instead of deleting them and not actually delete anything until > all of the preremove scripts have run. Then delete the files in the > list. Then remove the installed files. That's one solution, but it implies a level of communication between the preremove scripts and setup.exe that is currently non-existent. I suppose as a quick-and-dirty solution one could set up a TO-REMOVE-MANIFEST file somewhere (in /etc/preremove?) and require that all preremove scripts appended files to be deleted into that file instead of actually deleting them, but that isn't robust for a few reasons. One could even go a step further and have setup.exe replace /bin/rm with a program that does the required appending and leaves the files in place, but that's even less robust (e.g., what if the preremove script checks afterwards that the file really is deleted? or tries to create a *new* file in place of the old one, which could have been read-only?). Besides, this doesn't even begin to cover some more complex cases, like preremove scripts renaming files instead of deleting them; mucking with file contents (a la "sed -i"); and all other kinds of weird stuff one doesn't expect to see in preremove scripts until someone decides to do something "clever" and everything breaks. I'm not downplaying your suggestion, and it might be a good short-term workaround, but in the long term, some robust solution will have to be thought of. Igor -- http://cs.nyu.edu/~pechtcha/ |\ _,,,---,,_ [EMAIL PROTECTED] ZZZzz /,`.-'`' -. ;-;;,_ [EMAIL PROTECTED] |,4- ) )-,_. ,\ ( `'-' Igor Pechtchanski, Ph.D. '---''(_/--' `-'\_) fL a.k.a JaguaR-R-R-r-r-r-.-.-. Meow! "Happiness lies in being privileged to work hard for long hours in doing whatever you think is worth doing." -- Dr. Jubal Harshaw -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
