solver3: Remove Work::choice

Instead of having the historic choice here, follow MiniSAT and
use the assigned variable from the tail. This should also make
the Assume() function work now, albeit we still need to actually
migrate to it.

This is a first step towards refactoring the Solve() loop to use
a propagate/find next literal/assume it kind of loop, albeit there
is a bit more to prepare there as we need to also reinsert work
items when backtracking.

1 files changed, 4 insertions, 5 deletions

diff --git a/apt-pkg/solver3.cc b/apt-pkg/solver3.cc
index abc0af314..b97e3b694 100644
--- a/apt-pkg/solver3.cc
+++ b/apt-pkg/solver3.cc
@@ -901,13 +901,13 @@ APT::Solver::Clause APT::Solver::TranslateOrGroup(pkgCache::DepIterator start, p
    return clause;
 }
 
-void APT::Solver::Push(Work work)
+void APT::Solver::Push(Var var, Work work)
 {
    if (unlikely(debug >= 2))
       std::cerr << "Trying choice for " << work.toString(cache) << std::endl;
 
    choices.push_back(solved.size());
-   solved.push_back(Solved{Var(), std::move(work)});
+   solved.push_back(Solved{var, std::move(work)});
 }
 
 void APT::Solver::UndoOne()
@@ -958,7 +958,7 @@ bool APT::Solver::Pop()
 
    assert(choices.back() < solved.size());
    int itemsToUndo = solved.size() - choices.back();
-   auto choice = solved[choices.back()].work->choice;
+   auto choice = solved[choices.back()].assigned;
 
    for (; itemsToUndo; --itemsToUndo)
       UndoOne();
@@ -1059,8 +1059,7 @@ bool APT::Solver::Solve()
 	 }
 	 if (item.size > 1 || item.clause->optional)
 	 {
-	    item.choice = sol;
-	    Push(item);
+	    Push(sol, item);
 	 }
 	 if (unlikely(debug >= 3))
 	    std::cerr << "(try it: " << sol.toString(cache) << ")\n";