solver3: Filter installed Recommends

When inspecting Recommends of installed packages, filter
them to the installed packages only, as we want to avoid
switching between alternatives of recommended packages.

2 files changed, 39 insertions, 0 deletions

diff --git a/apt-pkg/solver3.cc b/apt-pkg/solver3.cc
index 052142658..c2877946c 100644
--- a/apt-pkg/solver3.cc
+++ b/apt-pkg/solver3.cc
@@ -964,6 +964,16 @@ APT::Solver::Clause APT::Solver::TranslateOrGroup(pkgCache::DepIterator start, p
 	    std::cerr << "Promoting new clause to hard dependency: " << clause.toString(cache) << std::endl;
 	 clause.optional = false;
       }
+      else if (not existing.end() && importantToKeep(start) && satisfied)
+      {
+	 if (unlikely(debug >= 3))
+	    std::cerr << "Restricting existing Recommends to installed packages: " << clause.toString(cache, true) << std::endl;
+	 // Erase the non-installed solutions. We will process this last and try to keep the previously installed
+	 // "best" solution installed.
+	 clause.solutions.erase(std::remove_if(clause.solutions.begin(), clause.solutions.end(), [this](auto var)
+					       { return var.CastPkg(cache)->CurrentVer == nullptr; }),
+				clause.solutions.end());
+      }
    }
 
    return clause;
diff --git a/test/integration/test-solver3-break-recommends b/test/integration/test-solver3-break-recommends
new file mode 100755
index 000000000..88051f5de
--- /dev/null
+++ b/test/integration/test-solver3-break-recommends
@@ -0,0 +1,29 @@
+#!/bin/sh
+set -e
+
+TESTDIR="$(readlink -f "$(dirname "$0")")"
+. "$TESTDIR/framework"
+setupenvironment
+configarchitecture 'amd64'
+
+insertpackage 'installed' 'root' 'all' '1' 'Recommends: a | b'
+insertpackage 'installed,unstable' 'a' 'all' '1'
+insertpackage 'unstable' 'b' 'all' '1'
+
+setupaptarchive
+
+msgmsg "b should not be installed"
+
+testsuccessequal "Reading package lists...
+Building dependency tree...
+The following packages will be REMOVED:
+  a
+0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
+Remv a [1]" aptget remove a -s
+
+testsuccessequal "Reading package lists...
+Building dependency tree...
+The following packages will be REMOVED:
+  a
+0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
+Remv a [1]" apt remove a -s