award points for positive dependencies again

Commit 9ec748ff103840c4c65471ca00d3b72984131ce4 from Feb 23 last year
adds a version check after 8daf68e366fa9fa2794ae667f51562663856237c
added 8 days earlier negative points for breaks/conflicts with the
intended that only dependencies which are satisfied propagate points
(aka: old conflicts do not).

The implementation was needlessly complex and flawed through preventing
positive dependencies from gaining points like they did before these
commits making library transitions harder instead of simpler. It worked
out anyhow most of the time out of pure 'luck' (and other ways of
gaining points) or got miss attributed to being a temporary hick-up.

Closes: 774924

apt-pkg/algorithms.cc

@@ -468,7 +468,7 @@ void pkgProblemResolver::MakeScores()
 	 if (D->Version != 0)
 	 {
 	    pkgCache::VerIterator const IV = Cache[T].InstVerIter(Cache);
-	    if (IV.end() == true || D.IsSatisfied(IV) != D.IsNegative())
+	    if (IV.end() == true || D.IsSatisfied(IV) == false)
 	       continue;
 	 }
 	 Scores[T->ID] += DepMap[D->Type];

test/integration/test-allow-scores-for-all-dependency-types

@@ -32,6 +32,11 @@ insertpackage 'multipleyes' 'foo' 'amd64' '2.2' 'Conflicts: bar (<= 3)'
 # having foo multiple times as conflict is a non-advisable hack in general
 insertpackage 'multipleyes' 'bar' 'amd64' '2.2' 'Conflicts: foo (<= 3), foo (<= 3)'
 
+#774924 - slightly simplified
+insertpackage 'jessie' 'login' 'amd64' '2' 'Pre-Depends: libaudit1 (>= 0)'
+insertpackage 'jessie' 'libaudit1' 'amd64' '2' 'Depends: libaudit-common (>= 0)'
+insertpackage 'jessie' 'libaudit-common' 'amd64' '2' 'Breaks: libaudit0, libaudit1 (<< 2)'
+
 cp rootdir/var/lib/dpkg/status rootdir/var/lib/dpkg/status-backup
 setupaptarchive
 
@@ -142,3 +147,26 @@ Inst foo [1] (2 versioned [amd64])
 Inst baz (2 versioned [amd64])
 Conf foo (2 versioned [amd64])
 Conf baz (2 versioned [amd64])' aptget install baz -st versioned
+
+# recreating the exact situation is hard, so we pull tricks to get the score
+cp -f rootdir/var/lib/dpkg/status-backup rootdir/var/lib/dpkg/status
+insertinstalledpackage 'gdm3' 'amd64' '1' 'Depends: libaudit0, libaudit0'
+insertinstalledpackage 'login' 'amd64' '1' 'Essential: yes'
+insertinstalledpackage 'libaudit0' 'amd64' '1'
+testequal 'Reading package lists...
+Building dependency tree...
+The following packages will be REMOVED:
+  gdm3 libaudit0
+The following NEW packages will be installed:
+  libaudit-common libaudit1
+The following packages will be upgraded:
+  login
+1 upgraded, 2 newly installed, 2 to remove and 0 not upgraded.
+Remv gdm3 [1]
+Remv libaudit0 [1]
+Inst libaudit-common (2 jessie [amd64])
+Conf libaudit-common (2 jessie [amd64])
+Inst libaudit1 (2 jessie [amd64])
+Conf libaudit1 (2 jessie [amd64])
+Inst login [1] (2 jessie [amd64])
+Conf login (2 jessie [amd64])' aptget dist-upgrade -st jessie