From ae39ac30330869f37defd229752e46c49e3be8e9 Mon Sep 17 00:00:00 2001
From: Mikael Zayenz Lagerkvist <lagerkvist@gecode.dev>
Date: Fri, 10 Jul 2026 16:04:56 +0200
Subject: [PATCH] branch: honor filter in random tie selection

---
 gecode/kernel/branch/view-sel.hpp |  4 +-
 test/branch/int.cpp               | 97 ++++++++++++++++++++++++++++++-
 2 files changed, 98 insertions(+), 3 deletions(-)

diff --git a/gecode/kernel/branch/view-sel.hpp b/gecode/kernel/branch/view-sel.hpp
index 32c7d68358..cab0b69033 100644
--- a/gecode/kernel/branch/view-sel.hpp
+++ b/gecode/kernel/branch/view-sel.hpp
@@ -520,8 +520,8 @@ namespace Gecode {
   void
   ViewSelRnd<View>::ties(Space& home, ViewArray<View>& x, int s,
                          int* ties, int& n,
-                         BrancherFilter<View>&) {
-    n=1; ties[0] = select(home,x,s);
+                         BrancherFilter<View>& f) {
+    n=1; ties[0] = select(home,x,s,f);
   }
   template<class View>
   void
diff --git a/test/branch/int.cpp b/test/branch/int.cpp
index c8947973f0..33837242ec 100644
--- a/test/branch/int.cpp
+++ b/test/branch/int.cpp
@@ -33,8 +33,104 @@
 
 #include "test/branch.hh"
 
+#include <gecode/int/branch.hh>
+#include <gecode/search.hh>
+
 namespace Test { namespace Branch {
 
+  /// Space for testing filtered random tie selection
+  class FilteredRndTiesSpace : public Gecode::Space {
+  public:
+    /// Variables to branch on
+    Gecode::IntVarArray x;
+
+    /// Initialize space
+    FilteredRndTiesSpace(Gecode::Rnd r)
+      : x(*this, 4, 0, 1) {
+      Gecode::IntVarArgs xa(x);
+      Gecode::ViewArray<Gecode::Int::IntView> xv(*this, xa);
+      Gecode::ViewSel<Gecode::Int::IntView>* vs[2] = {
+        Gecode::Int::Branch::viewsel(*this, Gecode::INT_VAR_RND(r)),
+        Gecode::Int::Branch::viewsel(*this, Gecode::INT_VAR_SIZE_MIN())
+      };
+      // Post directly so the random selector remains first in the tie chain.
+      Gecode::postviewvalbrancher<Gecode::Int::IntView,2,int,2>(
+        *this, xv, vs,
+        Gecode::Int::Branch::valselcommit(*this, Gecode::INT_VAL_MIN()),
+        [](const Gecode::Space&, Gecode::IntVar, int i) {
+          return (i == 0) || (i == 2);
+        }, nullptr);
+    }
+
+    /// Constructor for cloning
+    FilteredRndTiesSpace(FilteredRndTiesSpace& s)
+      : Gecode::Space(s) {
+      x.update(*this, s.x);
+    }
+
+    /// Copy space during cloning
+    virtual Gecode::Space* copy(void) {
+      return new FilteredRndTiesSpace(*this);
+    }
+  };
+
+  /// Test filtered random tie selection with accepted and rejected views
+  class FilteredRndTies : public Base {
+  public:
+    /// Create and register test
+    FilteredRndTies(void)
+      : Base("Int::Branch::FilteredRndTies") {}
+
+    /// Run test
+    virtual bool run(void) {
+      bool selected[2] = {false, false};
+
+      for (unsigned int seed = 1; seed <= 16; seed++) {
+        FilteredRndTiesSpace* probe =
+          new FilteredRndTiesSpace(Gecode::Rnd(seed));
+        if (probe->status() != Gecode::SS_BRANCH) {
+          delete probe;
+          return false;
+        }
+        const Gecode::Choice* c = probe->choice();
+        const Gecode::PosChoice& pc
+          = static_cast<const Gecode::PosChoice&>(*c);
+        const int p = pc.pos().pos;
+        delete c;
+        delete probe;
+        if ((p != 0) && (p != 2))
+          return false;
+        selected[p == 2] = true;
+
+        FilteredRndTiesSpace* root =
+          new FilteredRndTiesSpace(Gecode::Rnd(seed));
+        Gecode::Search::Options o;
+        o.c_d = 2;
+        o.a_d = 1;
+        Gecode::DFS<FilteredRndTiesSpace> e(root, o);
+        delete root;
+
+        int n = 0;
+        while (Gecode::Space* s = e.next()) {
+          FilteredRndTiesSpace* solution =
+            static_cast<FilteredRndTiesSpace*>(s);
+          if (solution->x[1].assigned() || solution->x[3].assigned()) {
+            delete solution;
+            return false;
+          }
+          delete solution;
+          n++;
+        }
+        if (n != 4)
+          return false;
+      }
+
+      return selected[0] && selected[1];
+    }
+  };
+
+  FilteredRndTies filtered_rnd_ties;
+
   /// %Test brancher with distinct propagator
   class Int : public IntTest {
   public:
@@ -63,4 +159,3 @@ namespace Test { namespace Branch {
 }}
 
 // STATISTICS: test-branch
-