Also change computation of Origin field for PPAs when generating the final

APT config; ideally we wouldn't have to duplicate this code though;
perhaps the removal of APT preferences file can be limited to hardy too.
Also add an Explanation: header in the final preferences.

debian/changelog

@@ -26,6 +26,10 @@ livecd-rootfs (0.99) UNRELEASED; urgency=low
   * Run apt-get update one more time after installing the moblin keyring
     package, to promote Release.gpg from APT's lists/partial/ to lists/.
     Ideally APT would do that for us on apt-key updates.
+  * Also change computation of Origin field for PPAs when generating the final
+    APT config; ideally we wouldn't have to duplicate this code though;
+    perhaps the removal of APT preferences file can be limited to hardy too.
+    Also add an Explanation: header in the final preferences.
 
  -- Loïc Minier <loic.minier@ubuntu.com>  Thu, 24 Sep 2009 11:52:25 +0200
 

livecd.sh

@@ -520,10 +520,15 @@ deb http://$PPAMIRROR/$PPA/ubuntu ${STE} main
 deb-src http://$PPAMIRROR/$PPA/ubuntu ${STE} main
 @@EOF
 
+        # handle PPAs named "ppa" specially; their Origin field in the Release
+        # file does not end with "-ppa" for backwards compatibility
+        origin="${PPA%/ppa}"
+        origin="${origin/\//-}"
         touch ${ROOT}etc/apt/preferences
         cat << @@EOF >> ${ROOT}etc/apt/preferences
+Explanation: This prefers the Personal Archive $PPA over the other sources
 Package: *
-Pin: release o=LP-PPA-${PPA/\//-}
+Pin: release o=LP-PPA-$origin
 Pin-Priority: 550
 @@EOF
     fi