Reset WbFieldRef->last_update After Simulation Reset

docs/reference/changelog-r2025.md

@@ -1,5 +1,9 @@
 # Webots R2025 Change Log
 
+## Webots R2025b
+  - Bug Fixes
+    - Fixed a bug causing supervisors to occasionally read stale field values after the simulation was reset ([#6758](https://github.com/cyberbotics/webots/pull/6758)).
+
 ## Webots R2025a
 Released on January 31st, 2025.
   - New Features
@@ -24,7 +28,7 @@ Released on January 31st, 2025.
     - Improved the image range of the rotating [Lidar](lidar.md) ([#6324](https://github.com/cyberbotics/webots/pull/6324)).
     - Show box-plane contact point normals when showing contact points ([#6678](https://github.com/cyberbotics/webots/pull/6678)).
     - Improved the speed and accuracy of box-plane collisions ([#6688](https://github.com/cyberbotics/webots/pull/6688)).
-    - Enabled the launching of MATLAB desktop from the extern launcher ([#6366](https://github.com/cyberbotics/webots/pull/6366)). 
+    - Enabled the launching of MATLAB desktop from the extern launcher ([#6366](https://github.com/cyberbotics/webots/pull/6366)).
     - Improved overlays visible in Overlays menu by adding all the robots in the menu list ([#6297](https://github.com/cyberbotics/webots/pull/6297)).
   - Cleanup
     - Removed deprecated `windowPosition`, `pixelSize` fields of [Display](display.md) node ([#6327](https://github.com/cyberbotics/webots/pull/6327)).

src/controller/c/messages.h

@@ -75,7 +75,6 @@
 #define C_SUPERVISOR_RELOAD_WORLD 52
 #define C_SUPERVISOR_SET_LABEL 53
 #define C_SUPERVISOR_SIMULATION_QUIT 54
-#define C_SUPERVISOR_SIMULATION_RESET 55
 #define C_SUPERVISOR_SIMULATION_CHANGE_MODE 56
 #define C_SUPERVISOR_SIMULATION_RESET_PHYSICS 57
 #define C_SUPERVISOR_START_MOVIE 58
@@ -101,6 +100,7 @@
 #define C_SUPERVISOR_NODE_GET_PROTO 78
 
 // ctr <-> sim
+#define C_SUPERVISOR_SIMULATION_RESET 55
 #define C_ROBOT_WAIT_FOR_USER_INPUT_EVENT 80
 #define C_ROBOT_WWI_MESSAGE 81
 #define C_SUPERVISOR_SAVE_WORLD 82

src/controller/c/supervisor.c

@@ -1295,6 +1295,15 @@ static void supervisor_read_answer(WbDevice *d, WbRequest *r) {
     case C_SUPERVISOR_MOVIE_STATUS:
       movie_status = request_read_uchar(r);
       break;
+    case C_SUPERVISOR_SIMULATION_RESET: {
+      // Clear cached field values
+      WbFieldStruct *field = field_list;
+      while (field) {
+        field->last_update = -DBL_MAX;
+        field = field->next;
+      }
+      break;
+    }
     case C_SUPERVISOR_SAVE_WORLD:
       save_status = request_read_uchar(r);
       break;

src/webots/nodes/utils/WbSupervisorUtilities.cpp

@@ -280,6 +280,7 @@ WbSupervisorUtilities::WbSupervisorUtilities(WbRobot *robot) : mRobot(robot) {
   //  otherwise, conflicts can occur in case of multiple controllers
   connect(this, &WbSupervisorUtilities::changeSimulationModeRequested, this, &WbSupervisorUtilities::changeSimulationMode,
           Qt::QueuedConnection);
+  connect(WbWorld::instance(), &WbWorld::resetRequested, this, &WbSupervisorUtilities::simulationReset, Qt::QueuedConnection);
 }
 
 WbSupervisorUtilities::~WbSupervisorUtilities() {
@@ -343,6 +344,7 @@ void WbSupervisorUtilities::initControllerRequests() {
   mNodesDeletedSinceLastStep.clear();
   mUpdatedFields.clear();
   mWatchedFields.clear();
+  mSimulationReset = false;
 }
 
 QString WbSupervisorUtilities::readString(QDataStream &stream) {
@@ -2347,6 +2349,11 @@ void WbSupervisorUtilities::writeAnswer(WbDataStream &stream) {
     }
     mVirtualRealityHeadsetOrientationRequested = false;
   }
+  if (mSimulationReset) {
+    stream << (short unsigned int)0;
+    stream << (unsigned char)C_SUPERVISOR_SIMULATION_RESET;
+    mSimulationReset = false;
+  }
 }
 
 void WbSupervisorUtilities::writeConfigure(WbDataStream &stream) {
@@ -2419,3 +2426,8 @@ QString WbSupervisorUtilities::createLabelUpdateString(const WbWrenLabelOverlay
     .arg(y)
     .arg(text.replace("\n", "\\n"));
 }
+
+void WbSupervisorUtilities::simulationReset(bool restartControllers) {
+  if (!restartControllers)  // If the controller is about to be restarted, there's no need to tell it to reset its own state
+    mSimulationReset = true;
+}

src/webots/nodes/utils/WbSupervisorUtilities.hpp

@@ -73,6 +73,7 @@ private slots:
   void removeTrackedContactPoints(QObject *obj);
   void removeTrackedPoseNode(QObject *obj);
   void removeTrackedField(QObject *obj);
+  void simulationReset(bool restartControllers);
 
 private:
   WbRobot *mRobot;
@@ -111,6 +112,7 @@ private slots:
   bool mNodeExportStringRequest;
   bool mIsProtoRegenerated;
   bool mShouldRemoveNode;
+  bool mSimulationReset;
 
   // pointer to a single integer: if not NULL, the new status has to be sent to the libController
   int *mAnimationStartStatus;

tests/api/controllers/supervisor_reset_simulation_fields/.gitignore

@@ -0,0 +1 @@
+/supervisor_reset_simulation_fields

tests/api/controllers/supervisor_reset_simulation_fields/Makefile

@@ -0,0 +1,25 @@
+# Copyright 1996-2023 Cyberbotics Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Webots Makefile system 
+#
+# You may add some variable definitions hereafter to customize the build process
+# See documentation in $(WEBOTS_HOME_PATH)/resources/Makefile.include
+
+
+# Do not modify the following: this includes Webots global Makefile.include
+null :=
+space := $(null) $(null)
+WEBOTS_HOME_PATH?=$(subst $(space),\ ,$(strip $(subst \,/,$(WEBOTS_HOME))))
+include $(WEBOTS_HOME_PATH)/resources/Makefile.include

tests/api/controllers/supervisor_reset_simulation_fields/supervisor_reset_simulation_fields.c

@@ -0,0 +1,56 @@
+/*
+ * Description:  Test Supervisor device API
+ *               This file contains tests of reset simulation method
+ */
+
+#include <webots/robot.h>
+#include <webots/supervisor.h>
+
+#include "../../../lib/ts_assertion.h"
+#include "../../../lib/ts_utils.h"
+
+#define TIME_STEP 32
+
+int main(int argc, char **argv) {
+  ts_setup(argv[1]);
+
+  const double initial_translation[3] = {0, 0, 1};
+  const double new_translation[3] = {1, 0, 0};
+  WbFieldRef translation_field = wb_supervisor_node_get_field(wb_supervisor_node_get_from_def("SOLID"), "translation");
+  if (strcmp(argv[1], "supervisor_reset_simulation_fields_resetter") == 0) {
+    wb_robot_step(TIME_STEP);
+    wb_robot_step(TIME_STEP);
+
+    // <Other controller verifies SOLID's inital position>
+
+    wb_robot_step(TIME_STEP);
+    wb_supervisor_simulation_reset();
+    wb_robot_step(TIME_STEP);  // We have to wait another step or else the reset will overwrite the new value
+    wb_supervisor_field_set_sf_vec3f(translation_field, new_translation);
+  } else {
+    wb_robot_step(TIME_STEP);
+    wb_robot_step(TIME_STEP);
+    const double *first_translation = wb_supervisor_field_get_sf_vec3f(translation_field);
+    ts_assert_vec3_equal(
+      first_translation[0], first_translation[1], first_translation[2], initial_translation[0], initial_translation[1],
+      initial_translation[2], "SOLID's initial position should be [%f, %f, %f] not [%f, %f, %f]", initial_translation[0],
+      initial_translation[1], initial_translation[2], first_translation[0], first_translation[1], first_translation[2]);
+    wb_robot_step(TIME_STEP);
+
+    // <Other controller resets the simulation>
+
+    wb_robot_step(TIME_STEP);
+
+    // <Other controller updates SOLID's position>
+
+    wb_robot_step(TIME_STEP);
+    const double *second_translation = wb_supervisor_field_get_sf_vec3f(translation_field);
+    ts_assert_vec3_equal(
+      second_translation[0], second_translation[1], second_translation[2], new_translation[0], new_translation[1],
+      new_translation[2], "SOLID's position should be [%f, %f, %f] not [%f, %f, %f] after reset", new_translation[0],
+      new_translation[1], new_translation[2], second_translation[0], second_translation[1], second_translation[2]);
+  }
+
+  ts_send_success();
+  return EXIT_SUCCESS;
+}

tests/api/worlds/supervisor_reset_simulation_fields.wbt

@@ -0,0 +1,53 @@
+#VRML_SIM R2025a utf8
+
+EXTERNPROTO "webots://tests/default/protos/TestSuiteSupervisor.proto"
+EXTERNPROTO "webots://tests/default/protos/TestSuiteEmitter.proto"
+
+WorldInfo {
+  info [
+    "Test that fields do not return stale values after reset"
+  ]
+  basicTimeStep 8
+  coordinateSystem "NUE"
+}
+Viewpoint {
+  orientation 0.3011392881427894 -0.8944857953945254 -0.3304698034227591 4.845225060401701
+  position 8.056890161252701 5.15602094221405 0.024334960209242112
+}
+Background {
+  skyColor [
+    0 0 1
+  ]
+}
+DirectionalLight {
+  direction 0 -1 0
+}
+DEF SOLID Solid {
+  translation 0 0 1
+}
+TestSuiteSupervisor {
+}
+Robot {
+  controller "supervisor_reset_simulation_fields"
+  controllerArgs [
+    "supervisor_reset_simulation_fields_checker"
+  ]
+  children [
+    TestSuiteEmitter {
+    }
+  ]
+  name "checker robot"
+  supervisor TRUE
+}
+Robot {
+  controller "supervisor_reset_simulation_fields"
+  controllerArgs [
+    "supervisor_reset_simulation_fields_resetter"
+  ]
+  children [
+    TestSuiteEmitter {
+    }
+  ]
+  name "receiver robot"
+  supervisor TRUE
+}