symlinked docs are different between architectures, depending on dpkg-deb package order

Looks like dpkg-deb is being called in a different order so pkgbinarymangler symlinks LGPL_EXCEPTION.txt to different packages.

On amd64:
pkgstripfiles: processing control file: debian/libqt4-xmlpatterns/DEBIAN/control, package libqt4-xmlpatterns, directory debian/libqt4-xmlpatterns
.. removing usr/share/doc/libqt4-xmlpatterns/changelog.gz
Searching for duplicated docs in dependency libqt4-network...
  symlinking LGPL_EXCEPTION.txt in libqt4-xmlpatterns to file in libqt4-network
  symlinking changelog.Debian.gz in libqt4-xmlpatterns to file in libqt4-network
Searching for duplicated docs in dependency libqtcore4...
dpkg-deb: warning: 'debian/libqt4-xmlpatterns/DEBIAN/control' contains user-defined field 'Original-Maintainer'
dpkg-deb: warning: ignoring 1 warning about the control file(s)

On i386:
pkgstripfiles: processing control file: debian/libqt4-xmlpatterns/DEBIAN/control, package libqt4-xmlpatterns, directory debian/libqt4-xmlpatterns
.. removing usr/share/doc/libqt4-xmlpatterns/changelog.gz
Searching for duplicated docs in dependency libqt4-network...
Searching for duplicated docs in dependency libqtcore4...
  symlinking LGPL_EXCEPTION.txt in libqt4-xmlpatterns to file in libqtcore4
  symlinking changelog.Debian.gz in libqt4-xmlpatterns to file in libqtcore4
dpkg-deb: warning: 'debian/libqt4-xmlpatterns/DEBIAN/control' contains user-defined field 'Original-Maintainer'
dpkg-deb: warning: ignoring 1 warning about the control file(s)

pkgstripfiles searches dependencies in the order of the Depends: field. Seems for some reason this is different on i386 and amd64.

Ah, turns out to not be an issue of the Depends: field itself, but in the order binaries are processed:

debfx | pitti: the order of the dependencies is the same but on i386 pkgbinarymangler has already processed libqt4-network before libqt4-xmlpatterns

any workaround?

Workaround:

rm -f /usr/share/doc/{libqt4-xmlpatterns,libqt4-network,libqtgui4}/{LGPL_EXCEPTION.txt,changelog.Debian.gz}
apt-get install -f

I had to run the workaround again today with one more package:
rm -f /usr/share/doc/{libqt4-xmlpatterns,libqt4-network,libqtgui4,libqt4-declarative}/{LGPL_EXCEPTION.txt,changelog.Debian.gz}

debhelper's dh_builddeb is predictable, it processes packages in the order they appear in debian/control. The problem in this particular case is that qt4-x11 runs them all in parallel:

   dh_builddeb -u -Zlzma -O--parallel
INFO: pkgstriptranslations version 106
INFO: pkgstriptranslations version 106
INFO: pkgstriptranslations version 106
INFO: pkgstriptranslations version 106
INFO: pkgstriptranslations version 106
INFO: pkgstriptranslations version 106
INFO: pkgstriptranslations version 106
INFO: pkgstriptranslations version 106
[...]

That's what makes the build order unpredictable.

For the record, I have created a test case in pkgbinarymangler now which reproduces that, and Colin, Adam, and I discussed a solution today. This will be fixed tomorrow morning.

This bug was fixed in the package pkgbinarymangler - 107

---------------
pkgbinarymangler (107) precise; urgency=low

  * test/run, test_doc_symlink(): Simplify installation of "Makefile".
  * test/run, test_doc_symlink(): Introduce some test library binary packages
    to check handling of transitive dependencies.
  * pkgstripfiles, symlink_doc(): If the link destination target is itself a
    link, resolve it to directly link to the final target instead of not
    symlinking the file at all.
  * test/run: Add new test cases test_doc_symlink_parallel_{fixed,unlimited}()
    which run the symlink test with DEB_BUILD_OPTIONS "parallel=4" and
    "parallel" respectively. Run through them three times as this is a race
    condition and does not trigger every time. This reproduces LP #893826.
  * Add dh_builddeb: Wrapper around the debhelper command which filters out
    the "parallel" option from $DEB_BUILD_OPTIONS. We must not run dpkg-deb in
    parallel as this breaks a predictable doc symlink structure which we
    require for multi-arch. (LP: #893826)
  * debian/pkgbinarymangler.install: Install dh_builddeb wrapper.
  * debian/pkgbinarymangler.{preinst,postrm}: Set up diversion for
    dh_builddeb.
 -- Martin Pitt <email address hidden> Tue, 29 Nov 2011 10:00:54 +0100

This bug was fixed in the package qt4-x11 - 4:4.7.4-1ubuntu5

---------------
qt4-x11 (4:4.7.4-1ubuntu5) precise; urgency=low

  * No-change rebuild against pkgbinarymangler with multi-arch doc symlinking
    fix. (LP: #893826)
 -- Martin Pitt <email address hidden> Tue, 29 Nov 2011 10:24:42 +0100

Verified that libqt4-xmlpatterns:i386 installs fine now.