[HEADSUP] Proposal for change in postinstall script handling (was Re: [RFC] incremental rebase)

Corinna Vinschen corinna-cygwin@cygwin.com
Wed Nov 19 12:47:00 GMT 2014


On Nov 19 12:38, Achim Gratz wrote:
> Corinna Vinschen writes:
> >> In any case, this is mainly about putting the mechanism in place or
> >> rather to specify it.  Making it usable would require support from
> >> cygport and upset/genini.
> >
> > Not upset, it seems.  IIUC the stratumification can firmly stay in
> > setup' s hands with some support from cygport.  Upset wouldn't even
> > notice it.
> 
> >> Using hidden groups (like the non-functional
> >> _PostInstallLast we already have) would be an obvious way to do that.
> >
> > Isn't that moot then?  Stratum z would do it for free...
> 
> In both cases the use of the prefix is what decides the stratum.
> Arguably that could be made explicit in setup.hint instead, but that
> would require extension of the data format and changes to tools that use
> the data.  As long as we're manually assigning those strata (or farming
> this out into cygport) then no such support would be needed indeed.
> 
> ANother question: setup is used by other projects it seems.  How do we
> ensure they either agree with us or are unaffected by this change?
> 
> > Makes sense.  And the naming convention?  No chance for collisions with
> > existing scripts?
> 
> The Cygwin Package Search says that no such postinstall scripts
> currently exist, so I'd say we're GTG with the prefix idea.

I'd like to have some more input here.  Maintainers, if you have any
input to this, please follow up.

> > Btw., the MTA discussion has shown another problem.  The problem is that
> > preremove/postinstall scripts are run on package update as well, because
> > setup doesn't allow to differ between install, update and uninstall.  Do
> > you think it's complicated to allow to differentiate this in setup, so
> > we can, for instance, handle this kind of package collisions better?
> 
> Setup always does a uninstall/install operation, so there really is no
> such thing as an update (that's what any other package manager I know of
> does as well).  I haven't been following the MTA discussions closely,

Due to the way setup always runs preremove/postinstall scripts, there's
no way for us to automate a sendmail alternative, as, for instance, in
Fedora.  Fedora gives different weights to different sendmail alternatives,
and it sets them up at install time.  We, OTOH, have to do that completely
user-drive from the config scripts.

Anyway, that's just an example.  It would be cool if we could better
control this behaviour.  A good start would be, perhaps, if the
postinstall and preremove scripts would get a parameter telling them
if this is an uninstall or an update.

> > cygwin-apps is in the list.  All projects using the cygwin-apps
> > CVS repo are subsumed here.
> 
> I looked at the project list from the Navigation bar, not the one in the
> drop-down.  Doh…  Request has been submitted.

...and approved.


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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