Address sdformat11 deprecations

cpp/scenario/gazebo/include/scenario/gazebo/helpers.h

@@ -149,9 +149,7 @@ namespace scenario::gazebo::utils {
     sdf::World renameSDFWorld(const sdf::World& world,
                               const std::string& newWorldName);
 
-    bool renameSDFModel(sdf::Root& sdfRoot,
-                        const std::string& newModelName,
-                        const size_t modelIndex = 0);
+    bool renameSDFModel(sdf::Root& sdfRoot, const std::string& newModelName);
 
     bool updateSDFPhysics(sdf::Root& sdfRoot,
                           const double maxStepSize,

cpp/scenario/gazebo/include/scenario/gazebo/utils.h

@@ -112,15 +112,15 @@ namespace scenario::gazebo::utils {
     /**
      * Get the name of a model from a SDF file.
      *
+     * @note sdformat supports only one model per SDF file.
+     *
      * @param fileName An SDF file. It could be either an absolute path
      *        to the file or the file name if the parent folder is part
      *        of the ``IGN_GAZEBO_RESOURCE_PATH`` environment variable.
-     * @param modelIndex The index of the model in the SDF file. By
-     *        default it finds the first model.
-     * @return The name of the model.
+     * @return The name of the model if the file was found and is valid,
+     *         an empty string otherwise.
      */
-    std::string getModelNameFromSdf(const std::string& fileName,
-                                    const size_t modelIndex = 0);
+    std::string getModelNameFromSdf(const std::string& fileName);
 
     /**
      * Get the name of a world from a SDF file.
@@ -130,7 +130,8 @@ namespace scenario::gazebo::utils {
      *        of the ``IGN_GAZEBO_RESOURCE_PATH`` environment variable.
      * @param worldIndex The index of the world in the SDF file. By
      *        default it finds the first world.
-     * @return The name of the world.
+     * @return The name of the world if the file was found and is valid,
+     *         an empty string otherwise.
      */
     std::string getWorldNameFromSdf(const std::string& fileName,
                                     const size_t worldIndex = 0);

cpp/scenario/gazebo/src/World.cpp

@@ -72,23 +72,16 @@ class World::Impl
                      const std::string& overrideModelName,
                      World& world)
     {
-        if (modelSdfRoot->ModelCount() != 1) {
-            sError << "The SDF file contains more than one model" << std::endl;
-            return false;
-        }
-
-        constexpr size_t ModelIndex = 0;
+        // NOTE: sdf::Root objects could only contain one sdf::Model starting
+        //       from sdformat11.
 
-        // Every SDF model has a name. In order to insert multiple models from
-        // the same SDF file, the modelData struct allows providing a scoped
-        // name.
+        // Name of the model to insert (allowing renaming from SDF)
         std::string finalModelEntityName;
 
         // Get the final name of the model
         if (overrideModelName.empty()) {
-            assert(modelSdfRoot->ModelByIndex(ModelIndex));
-            finalModelEntityName =
-                modelSdfRoot->ModelByIndex(ModelIndex)->Name();
+            assert(modelSdfRoot->Model());
+            finalModelEntityName = modelSdfRoot->Model()->Name();
         }
         else {
             finalModelEntityName = overrideModelName;
@@ -107,17 +100,15 @@ class World::Impl
 
         // Rename the model.
         // NOTE: The following is not enough because the name is not serialized
-        // to
-        //       string. We need also to operate directly on the raw element.
-        const_cast<sdf::Model*>(modelSdfRoot->ModelByIndex(ModelIndex))
+        //       to string. We need also to operate directly on the raw element.
+        const_cast<sdf::Model*>(modelSdfRoot->Model())
             ->SetName(finalModelEntityName);
 
         // Update the name in the sdf model. This is necessary because model
         // plugins are loaded right before the creation of the model entity and,
         // instead of receiving the model entity name, they receive the model
         // sdf name.
-        if (!utils::renameSDFModel(
-                *modelSdfRoot, finalModelEntityName, ModelIndex)) {
+        if (!utils::renameSDFModel(*modelSdfRoot, finalModelEntityName)) {
             sError << "Failed to rename SDF model" << std::endl;
             return false;
         }
@@ -128,18 +119,16 @@ class World::Impl
         }
 
         // Create the model entity
-        ignition::gazebo::Entity modelEntity;
-        modelEntity = this->sdfEntityCreator->CreateEntities(
-            modelSdfRoot->ModelByIndex(ModelIndex));
+        const ignition::gazebo::Entity modelEntity =
+            this->sdfEntityCreator->CreateEntities(modelSdfRoot->Model());
 
         // Attach the model entity to the world entity
         this->sdfEntityCreator->SetParent(modelEntity, world.m_entity);
 
         {
             // Check that the model name is correct
             assert(modelSdfRoot->ModelCount() == 1);
-            std::string modelNameSDF =
-                modelSdfRoot->ModelByIndex(ModelIndex)->Name();
+            std::string modelNameSDF = modelSdfRoot->Model()->Name();
             std::string modelNameEntity = utils::getExistingComponentData< //
                 ignition::gazebo::components::Name>(world.m_ecm, modelEntity);
             assert(modelNameSDF == modelNameEntity);
@@ -170,7 +159,7 @@ class World::Impl
         // We directly override the Pose component instead of using
         // Model::resetBasePose because it would just store a pose command that
         // needs to be processed by the Physics system. Overriding the
-        // component, instead, has direct effect.
+        // component, instead, has instantaneous effect.
         if (pose != core::Pose::Identity()) {
             utils::setComponentData<ignition::gazebo::components::Pose>(
                 world.m_ecm, modelEntity, utils::toIgnitionPose(pose));
@@ -409,8 +398,7 @@ bool World::insertModelFromFile(const std::string& path,
         return false;
     }
 
-    return pImpl.get()->insertModel(
-        modelSdfRoot, pose, overrideModelName, *this);
+    return pImpl->insertModel(modelSdfRoot, pose, overrideModelName, *this);
 }
 
 bool World::insertModelFromString(const std::string& sdfString,

cpp/scenario/gazebo/src/helpers.cpp

@@ -320,20 +320,20 @@ sdf::World utils::renameSDFWorld(const sdf::World& world,
     return renamedWorld;
 }
 
-bool utils::renameSDFModel(sdf::Root& sdfRoot,
-                           const std::string& newModelName,
-                           const size_t modelIndex)
+bool utils::renameSDFModel(sdf::Root& sdfRoot, const std::string& newModelName)
 {
-    const size_t initialNrOfModels = sdfRoot.ModelCount();
-
     // Create a new model with the scoped name
     auto renamedModel = std::make_shared<sdf::Element>();
     renamedModel->SetName("model");
     renamedModel->AddAttribute("name", "string", newModelName, true);
 
+    if (!sdfRoot.Model()) {
+        sError << "The sdf Root does not contain any model" << std::endl;
+        return false;
+    }
+
     // Get the first child of the original model element
-    sdf::ElementPtr child =
-        sdfRoot.ModelByIndex(modelIndex)->Element()->GetFirstElement();
+    sdf::ElementPtr child = sdfRoot.Model()->Element()->GetFirstElement();
 
     // Add all the children to the renamed model element
     while (child) {
@@ -343,19 +343,14 @@ bool utils::renameSDFModel(sdf::Root& sdfRoot,
     }
 
     // Remove the old model
-    auto originalModelElement = sdfRoot.ModelByIndex(modelIndex)->Element();
+    auto originalModelElement = sdfRoot.Model()->Element();
     originalModelElement->RemoveFromParent();
 
     // Insert the renamed model
     renamedModel->SetParent(sdfRoot.Element());
     sdfRoot.Element()->InsertElement(renamedModel);
 
-    if (sdfRoot.ModelCount() != initialNrOfModels) {
-        sError << "Failed to rename SDF model" << std::endl;
-        return false;
-    }
-
-    if (!sdfRoot.ModelNameExists(newModelName)) {
+    if (sdfRoot.Model()->Name() != newModelName) {
         sError << "Failed to insert renamed model in SDF root" << std::endl;
         return false;
     }

cpp/scenario/gazebo/src/utils.cpp

@@ -106,8 +106,7 @@ std::string utils::getSdfString(const std::string& fileName)
     return root->Element()->ToString("");
 }
 
-std::string utils::getModelNameFromSdf(const std::string& fileName,
-                                       const size_t modelIndex)
+std::string utils::getModelNameFromSdf(const std::string& fileName)
 {
     std::string absFileName = findSdfFile(fileName);
 
@@ -116,25 +115,18 @@ std::string utils::getModelNameFromSdf(const std::string& fileName,
         return {};
     }
 
-    auto root = utils::getSdfRootFromFile(absFileName);
+    const auto root = utils::getSdfRootFromFile(absFileName);
 
     if (!root) {
         return {};
     }
 
-    if (root->ModelCount() == 0) {
-        sError << "Didn't find any model in file " << fileName << std::endl;
-        return {};
-    }
-
-    if (modelIndex >= root->ModelCount()) {
-        sError << "Model with index " << modelIndex
-               << " not found. The model has only " << root->ModelCount()
-               << " model(s)" << std::endl;
-        return {};
+    if (const auto model = root->Model()) {
+        return model->Name();
     }
 
-    return root->ModelByIndex(modelIndex)->Name();
+    sError << "No model found in file " << fileName << std::endl;
+    return {};
 }
 
 std::string utils::getWorldNameFromSdf(const std::string& fileName,

tests/test_scenario/test_world.py

@@ -89,7 +89,7 @@ def test_world_api(gazebo: scenario.GazeboSimulator):
     assert world.insert_model(cube_urdf)
     assert len(world.model_names()) == 1
 
-    default_model_name = scenario.get_model_name_from_sdf(cube_urdf, 0)
+    default_model_name = scenario.get_model_name_from_sdf(cube_urdf)
     assert default_model_name in world.model_names()
     cube1 = world.get_model(default_model_name)
     # TODO: assert cube1