streett_to_generalize_buchi: fix handling of SCCs without Fin

The generalization to Streett-like of 7b5b8f34 was incomplete for this
case.  Thanks to František Blahoudek for reporting the bug.
Fixes #279.

* spot/twaalgos/totgba.cc (streett_to_generalized_buchi): Here.
* tests/core/remfin.test: Add more tests.

spot/twaalgos/totgba.cc

@@ -130,6 +130,7 @@ namespace spot
     acc_cond::mark_t fin;
     std::tie(inf, fin) = in->get_acceptance().used_inf_fin_sets();
     unsigned p = inf.count();
+    acc_cond::mark_t fin_not_inf = fin - inf;
 
     if (!p)
       return remove_fin(in);
@@ -150,7 +151,8 @@ namespace spot
 
     // Compute the acceptance sets present in each SCC
     unsigned nscc = si.scc_count();
-    std::vector<std::tuple<acc_cond::mark_t, acc_cond::mark_t, bool>> sccfi;
+    std::vector<std::tuple<acc_cond::mark_t, acc_cond::mark_t,
+                           bool, bool>> sccfi;
     sccfi.reserve(nscc);
     for (unsigned s = 0; s < nscc; ++s)
       {
@@ -160,21 +162,21 @@ namespace spot
         acc_cond::mark_t fin_wo_inf = 0U;
         for (unsigned mark: acc_fin.sets())
           if (!fin_to_infpairs[mark] || (fin_to_infpairs[mark] - acc_inf))
-            fin_wo_inf |= {mark};
+            fin_wo_inf.set(mark);
 
         acc_cond::mark_t inf_wo_fin = 0U;
         for (unsigned mark: acc_inf.sets())
           if (!inf_to_finpairs[mark] || (inf_to_finpairs[mark] - acc_fin))
-            inf_wo_fin |= {mark};
+            inf_wo_fin.set(mark);
 
-        sccfi.emplace_back(fin_wo_inf, inf_wo_fin, acc_fin == 0U);
+        sccfi.emplace_back(fin_wo_inf, inf_wo_fin,
+                           acc_fin == 0U, acc_inf == 0U);
       }
 
     auto out = make_twa_graph(in->get_dict());
     out->copy_ap_of(in);
     out->prop_copy(in, {false, false, false, false, false, true});
     out->set_generalized_buchi(p);
-    acc_cond::mark_t outall = out->acc().all_sets();
 
     // Map st2gba pairs to the state numbers used in out.
     typedef std::unordered_map<st2gba_state, unsigned,
@@ -207,7 +209,9 @@ namespace spot
         acc_cond::mark_t scc_fin_wo_inf;
         acc_cond::mark_t scc_inf_wo_fin;
         bool no_fin;
-        std::tie(scc_fin_wo_inf, scc_inf_wo_fin, no_fin) = sccfi[scc_src];
+        bool no_inf;
+        std::tie(scc_fin_wo_inf, scc_inf_wo_fin, no_fin, no_inf)
+          = sccfi[scc_src];
 
         for (auto& t: in->out(s.s))
           {
@@ -215,7 +219,6 @@ namespace spot
             acc_cond::mark_t acc = 0U;
 
             bool maybe_acc = maybe_acc_scc && (scc_src == si.scc_of(t.dst));
-
             if (pend != orig_copy)
               {
                 if (!maybe_acc)
@@ -232,7 +235,7 @@ namespace spot
                 // Label this transition with all non-pending
                 // inf sets.  The strip will shift everything
                 // to the correct numbers in the targets.
-                acc = (inf - pend).strip(fin - inf) & outall;
+                acc = (inf - pend).strip(fin - inf);
                 // Adjust the pending sets to what will be necessary
                 // required on the destination state.
                 if (sbacc)
@@ -249,9 +252,12 @@ namespace spot
               }
             else if (no_fin && maybe_acc)
               {
-                assert(maybe_acc);
+                // If the acceptance is (Fin(0) | Inf(1)) & Inf(2)
-                acc = outall;
+                // but we do not see any Fin set in this SCC, an
+                // mark {2} should become {1,2} before striping.
+                acc = (t.acc | (inf - scc_inf_wo_fin)).strip(fin_not_inf);
               }
+            assert((acc & out->acc().all_sets()) == acc);
 
             st2gba_state d(t.dst, pend);
             // Have we already seen this destination?
@@ -302,17 +308,6 @@ namespace spot
               }
           }
       }
-
-
-    // for (auto s: bs2num)
-    // {
-    //         std::cerr << s.second << " ("
-    //                   << s.first.s << ", ";
-    //         if (s.first.pend == orig_copy)
-    //           std::cerr << "-)\n";
-    //         else
-    //           std::cerr << s.first.pend << ")\n";
-    // }
     return out;
   }
 

tests/core/remfin.test

@@ -264,6 +264,12 @@ trans-acc --BODY-- State: 0 [!0&1] 5 [!0&1] 7 State: 1 [0&!1] 2 {2}
 [!0&1] 4 State: 7 [0&!1] 8 {3} [!0&!1] 7 {2} [0&!1] 3 {2} [!0&1] 5 {1}
 State: 8 [!0&1] 8 {2} [!0&!1] 3 {1} [!0&1] 4 State: 9 [0&!1] 6 {0 3}
 [!0&1] 2 --END--
+/* Exposed the bug from #279 */
+HOA: v1 States: 3 Start: 0 AP: 2 "b" "c" Acceptance: 3 Fin(0) &
+(Inf(1)&Inf(2)) properties: trans-labels explicit-labels trans-acc
+complete --BODY-- State: 0 [!0] 0 {1 2} [0] 0 {0 1 2} [0&!1] 1 [0&1] 2
+State: 1 [!0 | !1] 1 {1 2} [0&1] 2 {1} State: 2 [!1] 1 {1 2} [1] 2 {1}
+--END--
 EOF
 
 acctwelve='Inf(0)&Inf(1)&Inf(2)&Inf(3)&Inf(4)&Inf(5)'
@@ -814,6 +820,30 @@ State: 20 {0}
 [0&1] 16
 [!0&1] 20
 --END--
+HOA: v1
+States: 4
+Start: 0
+AP: 2 "b" "c"
+acc-name: generalized-Buchi 2
+Acceptance: 2 Inf(0)&Inf(1)
+properties: trans-labels explicit-labels trans-acc
+--BODY--
+State: 0
+[!0] 0
+[!0] 1
+[0] 0
+[0] 1
+[0&!1] 2
+[0&1] 3
+State: 1
+[!0] 1 {0 1}
+State: 2
+[!0 | !1] 2 {0 1}
+[0&1] 3 {0}
+State: 3
+[!1] 2 {0 1}
+[1] 3 {0}
+--END--
 EOF
 
 cat >expected-tgba <<EOF
@@ -1358,6 +1388,28 @@ State: 20
 [0&1] 16 {0}
 [!0&1] 20 {0}
 --END--
+HOA: v1
+States: 4
+Start: 0
+AP: 2 "b" "c"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels trans-acc
+--BODY--
+State: 0
+[t] 0
+[t] 1
+[0&!1] 2
+[0&1] 3
+State: 1
+[!0] 1 {0}
+State: 2
+[!0 | !1] 2 {0}
+[0&1] 3
+State: 3
+[!1] 2 {0}
+[1] 3
+--END--
 EOF
 
 run 0 $autfilt -H --remove-fin test1 > output
@@ -1368,9 +1420,18 @@ run 0 $autfilt -H --tgba test1 > output
 cat output
 diff -u output expected-tgba
 
-# make sure the above expected automata are correct
-autcross --language-preserved 'autfilt --remove-fin' 'autfilt --tgba' -Ftest1
 
-# try 10 small random automata just in case
+# Add 10 small random automata for the next case
-randaut -A'random 6' -Q10 -n10 3 |
+randaut -A'random 6' -Q10 -n10 3 -Hl >> test1
-autcross --verbose --language-preserved 'autfilt --remove-fin' 'autfilt --tgba'
+
+# make sure the above expected automata are correct
+autcross --verbose --language-preserved -Ftest1 \
+         'autfilt --remove-fin' 'autfilt --tgba'
+
+# do it again, but make sure autfilt uses streett_to_generalized_buchi
+# whenever buchi, and that autcross does not.  This helps findings bug
+# in streett_to_generalized_buchi().
+SPOT_STREETT_CONV_MIN=0 \
+autcross --language-preserved -Ftest1 \
+  'SPOT_STREETT_CONV_MIN=1 autfilt --remove-fin %H>%O' \
+  'SPOT_STREETT_CONV_MIN=1 autfilt --tgba %H>%O'