libexpat1 does not contain libexpat.so.0 in 8.04 Beta

Confirmed on Ubuntu 8.04 RC.

I confirm it on Hardy RC.
I also need libexpat.so.0 for OpenTTD.

Confirmed in 8.04 release.

The fix is to symlink the two, but I guess this needs to be fixed properly.. I found out about this trying to run OpenTTD too.

sudo ln -s /usr/lib/libexpat.so.1 /usr/lib/libexpat.so.0

Does the trick ^

This prevents wink to be built. Debian Maintainer is currently working on this issue, should be fixed with his next upload.
In the meantime, attached debdiff restore libexpat.so.0 until a proper fix is found.

Chris: can you please take a look at it?

Well, I'm currently working on it and have to say, that it might need some time. Because we are already in some freeze stage, the libexpat-transition will very probaly happen after Lenny is released.

For your problem: Isn't it possible to fix the broken programs [1] instead to reintroduce this very old compatibility symlink?

[1] Fixing means a) binNMU official packages (quick and dirty without a clean transition) and/or b) enforce fixing of the broken 3rd party packages by not providing the symlink. You will have to do the latter in every case, because I *will* drop this symlink definitly.

Could someone please invite Matthias Klose to this discussion?

what is the problem with openttd? it has no build dependency and no dependency on expat.

the problem with wink is unrelated:

dpkg-shlibdeps: failure: couldn't find library libstdc++.so.5 needed by debian/wink/usr/lib/wink/wink (its RPATH is '').
Note: libraries are not searched in other binary packages that do not have any shlibs or symbols file.
To help dpkg-shlibdeps find private libraries, you might need to set LD_LIBRARY_PATH.
dh_shlibdeps: command returned error code 512
make: *** [binary-arch] Error 1

please could somebody demonstrate the problem instead of saying "the symlink is missing"

wink currently FTBFS, see https://launchpad.net/ubuntu/+source/wink/1.5.1060-4/+build/604551:
dh_shlibdeps
dpkg-shlibdeps: failure: couldn't find library libexpat.so.0 needed by debian/wink/usr/lib/wink/wink (its RPATH is '').
Note: libraries are not searched in other binary packages that do not have any shlibs or symbols file.
To help dpkg-shlibdeps find private libraries, you might need to set LD_LIBRARY_PATH.
dh_shlibdeps: command returned error code 512
make: *** [binary-arch] Error 1

should be fixed in wink

For the record, wink is non-free (and comes without source).

wink fixed in Debian with 1.5.1060-5.

Just to be sure we don't loose sight of the original intent of this bug....

The bug is that 8.04 breaks binary compatibility with previous releases
by removing an interface (libexpat.so.0). The fact that wink has been
"fixed" is great, but does not address the fundamental issue.

> Matthias Klose
> please could somebody demonstrate the problem instead of saying "the symlink is missing"

I have an application. It runs fine on 6.06 LTS and 7.10. When I try
to run it on 8.04 it fails because 8.04 has broken binary compatibility
with previous releases by removing libexpat.so.0

Granted, I don't know what Ubuntu's binary compatibility policy is
(I haven't found it formally stated anywhere). But this breakage seems gratuitous.

Can you be a bit more specific and verbose, what exactly "breaks"?

Why should "binary compatibility" be broken by removing a link, that should have been never added?

To be honest: I miss the compelling reason to leave this link. wink has been fixed and no other packages were affected.

>Can you be a bit more specific and verbose, what exactly "breaks"?

I have an application that has a dependency on libexpat.so.0. It runs fine on 6.06.
It runs fine on 7.10. It fails to run on 8.04 because libexpat.so.0 does not exist on 8.04.

>Why should "binary compatibility" be broken by removing a link, that should have been never added?

Removing that link removes an interface from the OS. Removing a public interface
from the OS breaks binary compatibility.

> To be honest: I miss the compelling reason to leave this link. wink has been fixed and no other packages were affected.

Actually that logic is reversed. You need a compelling reason to remove libexpat.so.0.
Plus you need some confidence that the number of applications that will break
is mitigated somehow.

You can't possibly know about all software that runs on Ubuntu, so saying
"no other packages were affected" is pretty presumptuous.

Look, I'm not saying you can never, ever break compatibility. But when you do there
needs to be a very good reason why, and some confidence that the impact on
customers and developers is minimal.

> I have an application that has a dependency on libexpat.so.0. It runs fine on 6.06.
> It runs fine on 7.10. It fails to run on 8.04 because libexpat.so.0 does not exist on 8.04.

I'm really curious, where does this application come from and what's its
age, since /usr/lib/libexpat.so has pointed to libexpat.so.1 for many
years.

> You can't possibly know about all software that runs on Ubuntu, so saying
> "no other packages were affected" is pretty presumptuous.

It is a bit more than that: http://lists.debian.org/debian-release/2008/05/msg00428.html. With thanks to Kevin B. McCarty.

> It is a bit more than that

really? He did find exactly one package: wink.

Uploaded a package for hardy-proposed which (fixes a build failure), and provides the symlink in the wink package itself.

My encounter with this bug involves try to start httpd from a chroot jail. After all the shared libraries had been added, libexpat.so.0 was nowhere to be found in /usr/lib.

...adding the symlink manually, and copying the shared lib to the chroot has solved the problem.

sudo ln -s /usr/lib/libexpat.so.1 /usr/lib/libexpat.so.0

Thank you.

accepted into hardy-proposed, please test.

This bug was fixed in the package wink - 1.5.1060-5ubuntu1

---------------
wink (1.5.1060-5ubuntu1) intrepid; urgency=low

  * debian/rules:
    - Call dh_shlibdeps with -l$(CURDIR)/debian/wink/usr/lib/wink to
      link against libexpat.so.0, linked to libexpat.so.1 (LP: #218963).
  * debian/script/wink.sh
    - Export LD_LIBRARY_PATH to launch wink correctly (LP: #185868).
  * debian/control:
    - Update Maintainer field as per spec.

 -- Luca Falavigna <email address hidden> Fri, 13 Jun 2008 20:35:25 +0200

Version 1.5.1060-3ubuntu1.1 FTBFS due to missing libgtk2.0-dev.

I had the same problem with Wink. This solved the issue also for me:

sudo ln -s /usr/lib/libexpat.so.1 /usr/lib/libexpat.so.0

Version 1.5.1060-3ubuntu1.2 which fixes FTBFS waiting in unapproved queue.

Accepted into -proposed, please test and give feedback here. Please see https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

HARDY VERIFICATION

Using version 1.5.1060-3ubuntu1 from hardy-release:
$ wink
/usr/lib/wink/wink: error while loading shared libraries: libexpat.so.0: cannot open shared object file: No such file or directory
$

Using version 1.5.1060-3ubuntu1.2 from hardy-proposed:
$ wink
[Program runs fine]
$

Copied to hardy-updates.