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Fix a bug in spot.complete()

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spot.complete() could complete an empty co-Büchi automaton into an
automaton accepting everything.

* NEWS: Document it
* spot/twaalgos/complete.cc: Fix it
* tests/core/complete.test, tests/core/prodor.test: Test it
This commit is contained in:
Maximilien Colange 2017-08-28 17:15:10 +02:00
parent eb91ecf66f
commit 1b2f2a79c1
4 changed files with 59 additions and 7 deletions
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11
spot/twaalgos/complete.cc
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@ -69,7 +69,7 @@ namespace spot
loopmark = t.acc;
first = false;
}
// If this this not the first self loop and it as a
// If this this not the first self loop and it has a
// different acceptance mark, do not consider this
// state as a sink candidate: combining loops with
// different marks might be used to build an accepting
@ -107,7 +107,7 @@ namespace spot
for (unsigned i = 0; i < n; ++i)
{
bdd missingcond = bddtrue;
acc_cond::mark_t acc = 0U;
acc_cond::mark_t acc = um.second;
unsigned edge_to_sink = 0;
for (auto& t: aut->out(i))
{
@ -121,6 +121,8 @@ namespace spot
// In case the automaton uses edge-based acceptance,
// it does not matter what acceptance set we put the new
// edge into.
// EXCEPT if there is an incomplete sinkable state: completing it
// creates self-loops that must be rejecting.
//
// So in both cases, we put the edge in the same
// acceptance sets as the last outgoing edge of the
@ -147,10 +149,11 @@ namespace spot
}
else // otherwise, create the new edge.
{
// in case the automaton use state-based acceptance, propagate
// in case the automaton uses state-based acceptance, propagate
// the acceptance of the first edge to the one we add.
if (!aut->prop_state_acc().is_true())
if (!aut->prop_state_acc().is_true() && i != sink)
acc = 0U;
aut->new_edge(i, sink, missingcond, acc);
}
}