Introduce experimental 'never' pinning for sources

This allows disabling a repository by pinning it to 'never',
which is internally translated to a value of -32768 (or whatever
the minimum of short is).

This overrides any other pin for that repository. It can be used
to make sure certain sources are never used; for example, in
unattended-upgrades.

To prevent semantic changes to existing files, we substitute
min + 1 for every pin-priority: <min>. This is a temporary
solution, as we are waiting for an ABI break.

To add pins with that value, the special Pin-Priority
"never" may be used for now. It's unclear if that will
persist, or if the interface will change eventually.

1 files changed, 62 insertions, 3 deletions

diff --git a/test/integration/test-policy-pinning b/test/integration/test-policy-pinning
index 5676d1457..35e178871 100755
--- a/test/integration/test-policy-pinning
+++ b/test/integration/test-policy-pinning
@@ -315,15 +315,16 @@ testsuccessequal "coolstuff:
   Installed: 2.0~bpo1
   Candidate: $2
   Version table:
-     2.0~bpo2 $1
-       $1 file:${tmppath}/aptarchive backports/main all Packages
+     2.0~bpo2 ${3:-$1}
+       ${3:-$1} file:${tmppath}/aptarchive backports/main all Packages
  *** 2.0~bpo1 100
         100 ${tmppath}/rootdir/var/lib/dpkg/status
      1.0 500
         500 file:${tmppath}/aptarchive stable/main all Packages" apt policy coolstuff
 }
 currentpin '32767' '2.0~bpo2'
-currentpin '-32768' '2.0~bpo1'
+currentpin '-32768' '2.0~bpo1' '-32767'
+currentpin '-32767' '2.0~bpo1' '-32767'
 
 # Check for 0
 echo "Package: coolstuff
@@ -359,3 +360,61 @@ testsuccessequal "coolstuff:
         100 ${tmppath}/rootdir/var/lib/dpkg/status
      1.0 500
         500 file:${tmppath}/aptarchive stable/main all Packages" aptcache policy coolstuff
+
+
+# Check for override pins
+
+# Normal pins: First one wins
+echo "Package: coolstuff
+Pin: release n=backports
+Pin-Priority: 990
+
+Package: coolstuff
+Pin: release n=backports
+Pin-Priority: 991
+" > rootdir/etc/apt/preferences
+
+testsuccessequal "coolstuff:
+  Installed: 2.0~bpo1
+  Candidate: 2.0~bpo2
+  Version table:
+     2.0~bpo2 990
+        100 file:${tmppath}/aptarchive backports/main all Packages
+ *** 2.0~bpo1 100
+        100 ${tmppath}/rootdir/var/lib/dpkg/status
+     1.0 500
+        500 file:${tmppath}/aptarchive stable/main all Packages" aptcache policy coolstuff
+
+
+echo "Package: coolstuff
+Pin: release n=backports
+Pin-Priority: 990
+
+Package: *
+Pin: release n=backports
+Pin-Priority: never
+" > rootdir/etc/apt/preferences
+
+testsuccessequal "coolstuff:
+  Installed: 2.0~bpo1
+  Candidate: 2.0~bpo1
+  Version table:
+     2.0~bpo2 -32768
+       -32768 file:${tmppath}/aptarchive backports/main all Packages
+ *** 2.0~bpo1 100
+        100 ${tmppath}/rootdir/var/lib/dpkg/status
+     1.0 500
+        500 file:${tmppath}/aptarchive stable/main all Packages" aptcache policy coolstuff
+
+
+
+
+# Check for 0
+echo "Package: coolstuff
+Pin: release n=backports
+Pin-Priority: never
+" > rootdir/etc/apt/preferences
+
+testfailureequal "Reading package lists...
+E: ${tmppath}/rootdir/etc/apt/preferences: The special 'Pin-Priority: never' can only be used for 'Package: *' records" \
+ aptget install -s coolstuff -o PinPriority=0