Merge lp:~tapaal-ltl/verifypn/fireable-empty-preset-fix into lp:verifypn

[Nikolaj Jensen Ulrik]

When unfolding is-fireable(t) for t with empty preset, it becomes an AndCondition with no conditions, causing a segmentation fault when attempting to interact with it. This patch instead inserts True in that case, assuming an empty preset transition is always enabled.

[Peter Gjøl Jensen (peter-gjoel)]

LGTM.

review: Approve

[Jiri Srba (srba)]

review: Approve

=== modified file 'src/PetriEngine/PQL/Expressions.cpp'
--- src/PetriEngine/PQL/Expressions.cpp	2021-07-07 13:19:23 +0000
+++ src/PetriEngine/PQL/Expressions.cpp	2021-08-17 09:51:58 +0000
@@ -446,6 +446,9 @@
                 }
             }
             if(conds.size() == 1) _compiled = conds[0];
+            else if (conds.empty()) {
+                _compiled = BooleanCondition::TRUE_CONSTANT;
+            }
             else _compiled = std::make_shared<AndCondition>(conds);
             _compiled->analyze(context);
         }