Add namespace support for topic/service name

include/gz/sim/EntityComponentManager.hh

@@ -105,6 +105,7 @@ namespace gz
       /// \param[in] _name The name that should be given to the cloned entity.
       /// Set this to an empty string if the cloned entity name should be
       /// auto-generated to something unique.
+      /// \param[in] _ns The namespace that should be given to the cloned entity.
       /// \param[in] _allowRename True if _name can be modified to be a unique
       /// name if it isn't already a unique name. False if _name cannot be
       /// modified to be a unique name. If _allowRename is set to False, and
@@ -117,7 +118,8 @@ namespace gz
       /// cloned.
       /// \sa Clone
       public: Entity Clone(Entity _entity, Entity _parent,
-                  const std::string &_name, bool _allowRename);
+                  const std::string &_name, const std::string &_ns,
+                  bool _allowRename);
 
       /// \brief Get the number of entities on the server.
       /// \return Entity count.
@@ -371,13 +373,15 @@ namespace gz
       /// \param[in] _entity The entity to clone.
       /// \param[in] _parent The parent of the cloned entity.
       /// \param[in] _name The name that should be given to the cloned entity.
+      /// \param[in] _ns The namespace that should be given to the cloned entity.
       /// \param[in] _allowRename True if _name can be modified to be a unique
       /// name if it isn't already a unique name. False if _name cannot be
       /// modified to be a unique name.
       /// \return The cloned entity. kNullEntity is returned if cloning failed.
       /// \sa Clone
       private: Entity CloneImpl(Entity _entity, Entity _parent,
-                  const std::string &_name, bool _allowRename);
+                  const std::string &_name, const std::string &_ns,
+                  bool _allowRename);
 
       /// \brief A version of Each() that doesn't use a cache. The cached
       /// version, Each(), is preferred.

include/gz/sim/Util.hh

@@ -68,6 +68,23 @@ namespace gz
       const EntityComponentManager &_ecm, const std::string &_delim = "/",
       bool _includePrefix = true);
 
+    /// \brief Helper function to check whether any entity has a non-empty
+    /// namespace component.
+    /// \param[in] _ecm Immutable reference to ECM.
+    /// \return True if any entity has a non-empty namespace.
+    bool GZ_SIM_VISIBLE hasNamespace(
+        const EntityComponentManager &_ecm);
+
+  /// \brief Helper function to generate the full scoped namespace of an entity,
+  /// including namespaces inherited from all parent entities.
+  /// \param[in] _ecm Immutable reference to ECM.
+  /// \param[in] _entity Entity to get the scoped namespace for.
+  /// \param[in] _delim Delimiter to put between namespaces, defaults to "/".
+  /// \return Scoped namespace, or empty string if no namespace is found.
+  std::string GZ_SIM_VISIBLE scopedNamespace(
+      const EntityComponentManager &_ecm, const Entity &_entity,
+      const std::string &_delim = "/");
+
     /// \brief Helper function to get an entity given its scoped name.
     /// The scope may start at any level by default. For example, in this
     /// hierarchy:

include/gz/sim/components/Namespace.hh

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2026 Jiayi Cai
+ *
+ * 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
+ *
+ *     http://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.
+ *
+*/
+#ifndef GZ_SIM_COMPONENTS_NAMESPACE_HH_
+#define GZ_SIM_COMPONENTS_NAMESPACE_HH_
+
+#include <string>
+#include <gz/sim/components/Factory.hh>
+#include <gz/sim/components/Component.hh>
+#include <gz/sim/components/Serialization.hh>
+#include <gz/sim/config.hh>
+
+namespace gz
+{
+namespace sim
+{
+// Inline bracket to help doxygen filtering.
+inline namespace GZ_SIM_VERSION_NAMESPACE {
+namespace components
+{
+  /// \brief This component holds an entity's namespace.
+  using Namespace = Component<std::string, class NamespaceTag,
+      serializers::StringSerializer>;
+  GZ_SIM_REGISTER_COMPONENT("gz_sim_components.Namespace", Namespace)
+}
+}
+}
+}
+
+#endif

src/EntityComponentManager.cc

@@ -39,7 +39,9 @@
 #include "gz/sim/components/Factory.hh"
 #include "gz/sim/components/Joint.hh"
 #include "gz/sim/components/Link.hh"
+#include "gz/sim/components/Model.hh"
 #include "gz/sim/components/Name.hh"
+#include "gz/sim/components/Namespace.hh"
 #include "gz/sim/components/ParentEntity.hh"
 #include "gz/sim/components/ParentLinkName.hh"
 #include "gz/sim/components/Recreate.hh"
@@ -394,15 +396,16 @@ Entity EntityComponentManagerPrivate::CreateEntityImplementation(Entity _entity)
 
 /////////////////////////////////////////////////
 Entity EntityComponentManager::Clone(Entity _entity, Entity _parent,
-    const std::string &_name, bool _allowRename)
+    const std::string &_name, const std::string &_ns,
+    bool _allowRename)
 {
   // Clear maps so they're populated for the entity being cloned
   this->dataPtr->oldToClonedCanonicalLink.clear();
   this->dataPtr->oldModelCanonicalLink.clear();
   this->dataPtr->originalToClonedLink.clear();
   this->dataPtr->clonedToOriginalJointLinks.clear();
 
-  auto clonedEntity = this->CloneImpl(_entity, _parent, _name, _allowRename);
+  auto clonedEntity = this->CloneImpl(_entity, _parent, _name, _ns, _allowRename);
 
   if (kNullEntity != clonedEntity)
   {
@@ -455,7 +458,8 @@ Entity EntityComponentManager::Clone(Entity _entity, Entity _parent,
 
 /////////////////////////////////////////////////
 Entity EntityComponentManager::CloneImpl(Entity _entity, Entity _parent,
-    const std::string &_name, bool _allowRename)
+    const std::string &_name, const std::string &_ns,
+    bool _allowRename)
 {
   auto uniqueNameGenerated = false;
 
@@ -529,13 +533,30 @@ Entity EntityComponentManager::CloneImpl(Entity _entity, Entity _parent,
   }
   this->CreateComponent(clonedEntity, components::Name(clonedName));
 
+  auto originalNsComp = this->Component<components::Namespace>(_entity);
+  if (nullptr != originalNsComp)
+  {
+    std::string ns;
+    if (!_ns.empty())
+    {
+      ns = _ns;
+    }
+    else
+    {
+      // If the namespace is not provided, use the original entity's namespace.
+      ns = originalNsComp->Data();
+    }
+    this->CreateComponent(clonedEntity, components::Namespace(ns));
+  }
+
   // copy all components from _entity to clonedEntity
   for (const auto &type : this->ComponentTypes(_entity))
   {
-    // skip the Name and ParentEntity components since those were already
+    // skip the Name, Namespace and ParentEntity components since those were already
     // handled above
     if ((type == components::Name::typeId) ||
-        (type == components::ParentEntity::typeId))
+        (type == components::ParentEntity::typeId) ||
+        (type == components::Namespace::typeId))
       continue;
 
     auto originalComp = this->ComponentImplementation(_entity, type);
@@ -641,8 +662,9 @@ Entity EntityComponentManager::CloneImpl(Entity _entity, Entity _parent,
         name = nameComp->Data();
       }
     }
+
     auto clonedChild = this->CloneImpl(childEntity, clonedEntity, name,
-        _allowRename);
+        "", _allowRename);
     if (kNullEntity == clonedChild)
     {
       gzerr << "Cloning child entity [" << childEntity << "] failed.\n";

src/EntityComponentManager_TEST.cc

@@ -30,6 +30,7 @@
 #include "gz/sim/components/Joint.hh"
 #include "gz/sim/components/Link.hh"
 #include "gz/sim/components/Name.hh"
+#include "gz/sim/components/Namespace.hh"
 #include "gz/sim/components/ParentEntity.hh"
 #include "gz/sim/components/ParentLinkName.hh"
 #include "gz/sim/components/Pose.hh"
@@ -2814,11 +2815,13 @@ TEST_P(EntityComponentManagerFixture,
 
   Entity topLevelEntity = manager.CreateEntity();
   manager.CreateComponent(topLevelEntity, components::Name("topLevelEntity"));
+  manager.CreateComponent(topLevelEntity, components::Namespace("topLevelNs"));
   manager.CreateComponent(topLevelEntity, IntComponent(123));
   manager.CreateComponent(topLevelEntity, StringComponent("string0"));
 
   Entity childEntity1 = manager.CreateEntity();
   manager.CreateComponent(childEntity1, components::Name("childEntity1"));
+  manager.CreateComponent(childEntity1, components::Namespace("childNs1"));
   manager.CreateComponent(childEntity1,
       components::ParentEntity(topLevelEntity));
   manager.CreateComponent(childEntity1, IntComponent(456));
@@ -2827,11 +2830,14 @@ TEST_P(EntityComponentManagerFixture,
   Entity grandChildEntity1 = manager.CreateEntity();
   manager.CreateComponent(grandChildEntity1,
       components::Name("grandChildEntity1"));
+  manager.CreateComponent(grandChildEntity1,
+      components::Namespace("grandChildNs1"));
   manager.CreateComponent(grandChildEntity1,
       components::ParentEntity(childEntity1));
 
   Entity childEntity2 = manager.CreateEntity();
   manager.CreateComponent(childEntity2, components::Name("childEntity2"));
+  manager.CreateComponent(childEntity2, components::Namespace("childNs2"));
   manager.CreateComponent(childEntity2,
       components::ParentEntity(topLevelEntity));
   manager.CreateComponent(childEntity2, IntComponent(789));
@@ -2859,6 +2865,8 @@ TEST_P(EntityComponentManagerFixture,
             components::ParentEntity::typeId));
       CompareEntityComponents<components::Name>(manager, topLevelEntity,
           _clonedEntity, false);
+      CompareEntityComponents<components::Namespace>(manager, topLevelEntity,
+          _clonedEntity, true);
       CompareEntityComponents<IntComponent>(manager, topLevelEntity,
           _clonedEntity, true);
       CompareEntityComponents<StringComponent>(manager, topLevelEntity,
@@ -2869,7 +2877,7 @@ TEST_P(EntityComponentManagerFixture,
 
   // clone the topLevelEntity
   auto clonedTopLevelEntity =
-    manager.Clone(topLevelEntity, kNullEntity, "", allowRename);
+    manager.Clone(topLevelEntity, kNullEntity, "", "", allowRename);
   EXPECT_EQ(8u, manager.EntityCount());
   clonedEntities.insert(clonedTopLevelEntity);
   validateTopLevelClone(clonedTopLevelEntity);
@@ -2887,20 +2895,24 @@ TEST_P(EntityComponentManagerFixture,
       EXPECT_EQ(clonedTopLevelEntity, parentComp->Data());
       CompareEntityComponents<components::Name>(manager, _clonedChild,
           _originalChild, false);
+      CompareEntityComponents<components::Namespace>(manager, _clonedChild,
+          _originalChild, true);
       CompareEntityComponents<IntComponent>(manager, _clonedChild,
           _originalChild, true);
       CompareEntityComponents<StringComponent>(manager, _clonedChild,
           _originalChild, true);
     };
 
   auto validateGrandChildClone =
-    [&](const Entity _clonedEntity, bool _sameParent)
+    [&](const Entity _clonedEntity, bool _sameNs, bool _sameParent)
     {
       EXPECT_NE(kNullEntity, _clonedEntity);
       EXPECT_EQ(manager.ComponentTypes(_clonedEntity),
           manager.ComponentTypes(grandChildEntity1));
       CompareEntityComponents<components::Name>(manager, _clonedEntity,
           grandChildEntity1, false);
+      CompareEntityComponents<components::Namespace>(manager, _clonedEntity,
+          grandChildEntity1, _sameNs);
       CompareEntityComponents<components::ParentEntity>(manager,
           _clonedEntity, grandChildEntity1, _sameParent);
       EXPECT_TRUE(manager.EntitiesByComponents(
@@ -2930,7 +2942,7 @@ TEST_P(EntityComponentManagerFixture,
 
       ASSERT_EQ(1u, clonedGrandChildren.size());
       clonedEntities.insert(clonedGrandChildren[0]);
-      validateGrandChildClone(clonedGrandChildren[0], false);
+      validateGrandChildClone(clonedGrandChildren[0], true, false);
       auto parentComp =
         manager.Component<components::ParentEntity>(clonedGrandChildren[0]);
       ASSERT_NE(nullptr, parentComp);
@@ -2950,31 +2962,33 @@ TEST_P(EntityComponentManagerFixture,
     EXPECT_TRUE(comparedToOriginalChild);
   }
 
-  // clone a child entity
+  // clone a child entity with a namespace provided
   auto grandChildParentComp =
     manager.Component<components::ParentEntity>(grandChildEntity1);
   ASSERT_NE(nullptr, grandChildParentComp);
   auto clonedGrandChildEntity = manager.Clone(grandChildEntity1,
-      grandChildParentComp->Data(), "", allowRename);
+      grandChildParentComp->Data(), "", "clonedGrandChildNs", allowRename);
   EXPECT_EQ(9u, manager.EntityCount());
   clonedEntities.insert(clonedGrandChildEntity);
-  validateGrandChildClone(clonedGrandChildEntity, true);
+  validateGrandChildClone(clonedGrandChildEntity, false, true);
 
-  // Try cloning an entity with a name that already exists, but allow renaming.
-  // This should succeed and generate a cloned entity with a unique name.
+  // Try cloning an entity with a name that already exists, but allow renaming
+  // and without a namespace provided.
+  // This should succeed and generate a cloned entity with a unique name
+  // and a same namespace.
   const auto existingName = "grandChildEntity1";
   EXPECT_NE(kNullEntity,
       manager.EntityByComponents(components::Name(existingName)));
   auto renamedClonedEntity = manager.Clone(grandChildEntity1,
-      grandChildParentComp->Data(), existingName, allowRename);
+      grandChildParentComp->Data(), existingName, "", allowRename);
   EXPECT_EQ(10u, manager.EntityCount());
   clonedEntities.insert(clonedGrandChildEntity);
-  validateGrandChildClone(renamedClonedEntity, true);
+  validateGrandChildClone(renamedClonedEntity, true, true);
 
   // Try cloning an entity with a name that already exists, without allowing
   // renaming. This should fail since entities should have unique names.
   auto failedClonedEntity = manager.Clone(grandChildEntity1,
-      grandChildParentComp->Data(), existingName, noAllowRename);
+      grandChildParentComp->Data(), existingName, "", noAllowRename);
   EXPECT_EQ(10u, manager.EntityCount());
   EXPECT_EQ(kNullEntity, failedClonedEntity);
 
@@ -3010,7 +3024,7 @@ TEST_P(EntityComponentManagerFixture,
 
   // clone a joint that has a parent and child link.
   auto clonedParentModelEntity = manager.Clone(parentModelEntity, kNullEntity,
-      "", true);
+      "", "", true);
   ASSERT_NE(kNullEntity, clonedParentModelEntity);
   // We just cloned a model with two links and a joint, a total of 4 new
   // entities.
@@ -3062,7 +3076,7 @@ TEST_P(EntityComponentManagerFixture,
 
   // try to clone an entity that does not exist
   EXPECT_EQ(kNullEntity, manager.Clone(kNullEntity, topLevelEntity, "",
-        allowRename));
+        "", allowRename));
   EXPECT_EQ(18u, manager.EntityCount());
 }
 

src/SdfEntityCreator.cc

@@ -70,6 +70,7 @@
 #include "gz/sim/components/Material.hh"
 #include "gz/sim/components/Model.hh"
 #include "gz/sim/components/Name.hh"
+#include "gz/sim/components/Namespace.hh"
 #include "gz/sim/components/NavSat.hh"
 #include "gz/sim/components/ParentEntity.hh"
 #include "gz/sim/components/ParentLinkName.hh"
@@ -526,6 +527,16 @@ Entity SdfEntityCreator::CreateEntities(const sdf::Model *_model,
       components::Pose(ResolveSdfPose(_model->SemanticPose())));
   this->dataPtr->ecm->CreateComponent(modelEntity,
       components::Name(_model->Name()));
+  if (_model->Namespace().has_value())
+  {
+    this->dataPtr->ecm->CreateComponent(modelEntity,
+        components::Namespace(_model->Namespace().value()));
+  }
+  else
+  {
+    this->dataPtr->ecm->CreateComponent(modelEntity,
+        components::Namespace(""));
+  }
   bool isStatic = _model->Static() || _staticParent;
   this->dataPtr->ecm->CreateComponent(modelEntity,
       components::Static(isStatic));