Re: Bug#898627: man-db: dependency loop

[Ian Jackson <ijackson@chiark.greenend.org.uk>]

Colin Watson writes ("Re: Bug#898627: man-db: dependency loop"):
> On Mon, May 14, 2018 at 02:14:56PM +0200, Philipp Marek wrote:
> >     # apt-get -f install
> >     dpkg: Cycle in triggers found:
> >      Chain of packages, which triggers might be the culprit:
> >       man-db -> man-db
> >      required triggers of packages that can't be resolved:
> >       man-db: /usr/share/man
> >       libc-bin: ldconfig
> >     dpkg: Error while configureing package man-db (--configure):
> >      Triggers build a loop, aborted
...
> I've never seen this myself.  I guess it's due to man-db having
> "interest-noawait /usr/share/man" in its triggers and itself shipping
> files in /usr/share/man; but shouldn't dpkg notice that this is
> trivially resolved by configuring man-db and not consider it as a cycle?
> In any case I don't see any way to exclude man-db itself from the file
> trigger if that's not the case.

This trigger loop can only occur due to postinsts, not due to static
files.  The basic thing is that since package A's postinst (run for
trigger resolution) can can trigger package B's postinst to run, and
vice versa, this might lead to a loop.

Does the man-db or libc-bin postinst explicitly trigger
/usr/share/man ?

Ian.

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