fix: clear[] crashed after a fire whose front had stopped

CHANGELOG.md

@@ -58,6 +58,8 @@ Merged since v2.5.0, not yet released.
 - `StringRepresentation` kept its output buffer, current level and GeoJSON
   cursor in file-scope globals shared by every instance. They are now members.
   ([#178])
+- `clear[]` no longer crashes after a simulation whose fire front stopped
+  everywhere, for instance an ignition in non-burnable fuel. ([#194])
 
 ### Changed
 
@@ -189,3 +191,4 @@ repository stays easy to return to.
 [#178]: https://github.com/forefireAPI/forefire/pull/178
 [#180]: https://github.com/forefireAPI/forefire/pull/180
 [#183]: https://github.com/forefireAPI/forefire/pull/183
+[#194]: https://github.com/forefireAPI/forefire/pull/194

src/TimeTable.cpp

@@ -71,6 +71,7 @@ FFEvent* TimeTable::getUpcomingEvent(){
 		decrement();
 	} else if ( size() == 1 ) {
 		// this is the only event left
+		head = nullptr;
 		decrement();
 	} else {
 		// no events left to be treated (size=0)

tests/unit/CMakeLists.txt

@@ -12,7 +12,8 @@ add_executable(forefire_unit_tests
     test_flux_models.cpp
     test_http_server.cpp
     test_model_registry.cpp
-    test_propagation_models.cpp)
+    test_propagation_models.cpp
+    test_timetable.cpp)
 
 target_link_libraries(forefire_unit_tests PRIVATE forefireL)
 target_include_directories(forefire_unit_tests PRIVATE
@@ -27,7 +28,7 @@ endif()
 
 # doctest groups its cases into suites; registering one CTest entry per suite
 # keeps `ctest` output useful without needing doctest's CMake integration.
-foreach(_suite "model registry" "propagation models" "flux models" "http server")
+foreach(_suite "model registry" "propagation models" "flux models" "http server" "timetable")
     string(REPLACE " " "_" _suite_id "${_suite}")
     add_test(NAME "unit.${_suite_id}"
              COMMAND forefire_unit_tests --test-suite=${_suite} --no-skipped-summary)

tests/unit/test_timetable.cpp

@@ -0,0 +1,52 @@
+/**
+ * @file test_timetable.cpp
+ * @brief The event queue once its last event has been taken out.
+ * @copyright Copyright (C) 2025 ForeFire, Fire Team, SPE, CNRS/Universita di Corsica.
+ * @license This program is free software; See LICENSE file for details. (See LICENSE file).
+ */
+
+#include "doctest/doctest.h"
+
+#include "FFEvent.h"
+#include "TimeTable.h"
+
+#include <limits>
+
+using libforefire::FFEvent;
+using libforefire::TimeTable;
+
+TEST_SUITE("timetable") {
+
+TEST_CASE("clear() after the last event was dropped on reinsertion") {
+    TimeTable table;
+    table.insert(new FFEvent(nullptr, 1.0, "none"));
+
+    // A node that stopped gets an infinite time, and insert() deletes its event.
+    FFEvent* last = table.getUpcomingEvent();
+    last->setNewTime(std::numeric_limits<double>::infinity());
+    table.insert(last);
+
+    table.clear();
+
+    FFEvent* next = new FFEvent(nullptr, 2.0, "none");
+    table.insert(next);
+    CHECK(table.getUpcomingEvent() == next);
+    delete next;
+}
+
+TEST_CASE("dropping an atom's events spares the event being processed") {
+    TimeTable table;
+    FFEvent* event = new FFEvent(nullptr, 1.0, "none");
+    table.insert(event);
+
+    FFEvent* upcoming = table.getUpcomingEvent();
+    REQUIRE(upcoming == event);
+    table.dropAtomEvents(nullptr);
+
+    upcoming->setNewTime(2.0);
+    table.insert(upcoming);
+    CHECK(table.getUpcomingEvent() == event);
+    delete event;
+}
+
+}