[regression] libical 0.48 escapes X properties, but doesn't unescape them

I am running current 12.04Beta and caught this one as part of a fix evolution requires to workaround this problem with ical

ii libical0 0.48-1

This link describes the problem, test case and resolution,
http://sourceforge.net/mailarchive/forum.php?thread_name=1327947491.31941.3.camel%40localhost&forum_name=freeassociation-devel

I copied it below (removing the link so that launchpad would not confuse it with the related evolution bug).

It appears it might affect other packages besides evolution per "apt-cache rdepends libical0"

--

Hi,
I found a regression (actually, not me, but reporter of [1]'s downstream
bug found an issue which led to this being found) in libical 0.48. It
escapes strings on set of X properties, but doesn't unescape them on get.

See the attached test2.c, where I try to set a value which contains
quotes to an X property, and when reading it I get the quotes escaped.
The result of the test program looks like this:
> set 'string with "quotes" used', got 'string with \"quotes\" used',
> same:no!!!

This breaks CalDAV, which stores ETag values as they are received by the
server, and servers I tested this with (which is Google and DAViCal)
return ETags quoted, and expect them the same.

I've a workaround in evolution's CalDAV for now, but I do not know what
else this new behavior can break, thus it'll be good to have this fixed,
because it's expected that one gets what one sets.

Note the standard properties like SUMMARY don't suffer of this issue.

 Thanks and bye,
 Milan

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: libical0 0.48-1
ProcVersionSignature: Ubuntu 3.2.0-18.29-generic 3.2.9
Uname: Linux 3.2.0-18-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 1.94.1-0ubuntu2
Architecture: amd64
Date: Thu Mar 15 00:31:57 2012
ProcEnviron:
 TERM=xterm
 LANG=en_US.utf8
 SHELL=/bin/bash
SourcePackage: libical
UpgradeStatus: Upgraded to precise on 2012-03-13 (1 days ago)