work around issue #317

* spot/twaalgos/cobuchi.cc: Call sbacc() on transition-based input.
* tests/Makefile.am: Remove XFAIL_TESTS.
* NEWS: Adjust.

NEWS

@@ -33,7 +33,8 @@ New in spot 2.4.4.dev (net yet released)
   - ltl2tgba, autfilt, and dstar2tgba have some new '--cobuchi' option
     to force co-Büchi acceptance on the output.  Beware: if the input
     language is not co-Büchi realizable the output automaton will
-    recognize a superset of the input.
+    recognize a superset of the input.  Currently, the output is
+    always state-based.
 
   - genltl learned to generate six new families of formulas, taken from
     the SYNTCOMP competition on reactive synthesis, and from from
@@ -97,7 +98,7 @@ New in spot 2.4.4.dev (net yet released)
     these four functions.  The language of produced automata include
     the original language, but may be larger if the original automaton
     is not co-Büchi realizable.  Based on Boker & Kupferman FOSSACS'11
-    paper.
+    paper.  Currently only supports state-based output.
 
   - spot::scc_info::states_on_acc_cycle_of() return all states
     visited by any accepting cycle of the specified SCC.  It only

spot/twaalgos/cobuchi.cc

@@ -31,6 +31,7 @@
 #include <spot/twaalgos/totgba.hh>
 #include <spot/twaalgos/isdet.hh>
 #include <spot/twaalgos/strength.hh>
+#include <spot/twaalgos/sbacc.hh>  // For issue #317
 
 #include <stack>
 #include <unordered_map>
@@ -274,6 +275,11 @@ namespace spot
       throw std::runtime_error("dnf_to_nca() only works with DNF acceptance "
                                "condition");
 
+    // FIXME: At the moment this algorithm does not support
+    // transition-based acceptance.  See issue #317.  Once that is
+    // fixed we may remove the next line.
+    ref = sbacc(std::const_pointer_cast<twa_graph>(ref));
+
     auto streett_aut = spot::dnf_to_streett(ref, true);
 
     std::vector<acc_cond::rs_pair> pairs;
@@ -609,6 +615,11 @@ namespace spot
       throw std::runtime_error("nsa_to_dca() only works with Streett-like or "
                                "Parity acceptance condition");
 
+    // FIXME: At the moment this algorithm does not support
+    // transition-based acceptance.  See issue #317.  Once that is
+    // fixed we may remove the next line.
+    aut = sbacc(std::const_pointer_cast<twa_graph>(aut));
+
     // Get states that must be visited infinitely often in NCA.
     vect_nca_info nca_info;
     nsa_to_nca(aut, named_states, &nca_info);
@@ -635,6 +646,11 @@ namespace spot
       throw std::runtime_error("dnf_to_dca() only works with DNF (Rabin-like "
                                "included) acceptance condition");
 
+    // FIXME: At the moment this algorithm does not support
+    // transition-based acceptance.  See issue #317.  Once that is
+    // fixed we may remove the next line.
+    aut = sbacc(std::const_pointer_cast<twa_graph>(aut));
+
     // Get states that must be visited infinitely often in NCA.
     vect_nca_info nca_info;
     dnf_to_nca(aut, false, &nca_info);

tests/Makefile.am

@@ -315,9 +315,6 @@ TESTS_twa = \
   core/parity2.test \
   core/ltlsynt.test
 
-# Issue #317.
-XFAIL_TESTS = core/dca2.test
-
 ############################## PYTHON ##############################
 
 if USE_PYTHON