diff -Nru perl-5.14.2/debian/changelog perl-5.14.2/debian/changelog
--- perl-5.14.2/debian/changelog	2011-12-16 11:31:26.000000000 +0000
+++ perl-5.14.2/debian/changelog	2012-03-23 14:59:30.000000000 +0000
@@ -1,3 +1,11 @@
+perl (5.14.2-6ubuntu2) precise; urgency=low
+
+  * Have perl, perl-modules, and perl-base conflict with versions of
+    mono-gac requiring File::Basename, to ensure a smooth upgrade from lucid.
+    LP: #948848.
+
+ -- Steve Langasek <steve.langasek@ubuntu.com>  Fri, 23 Mar 2012 07:59:20 -0700
+
 perl (5.14.2-6ubuntu1) precise; urgency=low
 
   * debian/control: Add doc-base conflict also to perl, perl-modules, and
diff -Nru perl-5.14.2/debian/control perl-5.14.2/debian/control
--- perl-5.14.2/debian/control	2011-12-16 11:31:05.000000000 +0000
+++ perl-5.14.2/debian/control	2012-03-23 06:51:33.000000000 +0000
@@ -19,7 +19,7 @@
 Pre-Depends: ${shlibs:Depends}, dpkg (>= 1.14.20)
 Conflicts: safe-rm (<< 0.8),
  update-inetd (<< 4.41),
- doc-base (<< 0.10.3)
+ doc-base (<< 0.10.3), mono-gac (<< 2.10.8.1-1ubuntu1)
 Breaks: autoconf2.13 (<< 2.13-45),
  libscalar-list-utils-perl (<< 1:1.23),
  libfile-spec-perl (<< 3.3300),
@@ -220,7 +220,7 @@
  libfile-path-perl,
  libshell-perl,
  libperl4-corelibs-perl
-Conflicts: doc-base (<< 0.10.3)
+Conflicts: doc-base (<< 0.10.3), mono-gac (<< 2.10.8.1-1)
 Description: Core Perl modules
  Architecture independent Perl modules.  These modules are part of Perl and
  required if the `perl' package is installed.
@@ -271,7 +271,7 @@
 Priority: standard
 Architecture: any
 Depends: perl-base (= ${binary:Version}), perl-modules (>= ${source:Version}), ${shlibs:Depends}
-Conflicts: libjson-pp-perl (<< 2.27200-2), doc-base (<< 0.10.3)
+Conflicts: libjson-pp-perl (<< 2.27200-2), doc-base (<< 0.10.3), mono-gac (<< 2.10.8.1-1)
 Breaks: perl-doc (<< ${Upstream-Version}-1),
  libdigest-md5-perl (<< 2.51),
  libmime-base64-perl (<< 3.13),