From dfe8e45101382a6afb579550259bdb15e21764ef Mon Sep 17 00:00:00 2001
From: Alessio Quaglino <quaglino@google.com>
Date: Tue, 1 Oct 2024 09:13:43 -0700
Subject: [PATCH] Namespace plugin instances when attaching.

Fixes #2112.

PiperOrigin-RevId: 681045462
Change-Id: I2c945c5405fcb91e0f9a1b0b1e94f68d174c84ee
---
 src/user/user_mesh.cc      |  3 +++
 src/user/user_model.cc     |  1 +
 src/user/user_objects.cc   | 22 ++++++++++++++++++++++
 src/user/user_objects.h    |  1 +
 test/user/user_api_test.cc | 12 +++++++++---
 5 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/src/user/user_mesh.cc b/src/user/user_mesh.cc
index d03fc42b..f04cf1ab 100644
--- a/src/user/user_mesh.cc
+++ b/src/user/user_mesh.cc
@@ -230,6 +230,9 @@ void mjCMesh::NameSpace(const mjCModel* m) {
   if (meshdir_.empty()) {
     meshdir_ = FilePath(m->spec_meshdir_);
   }
+  if (!plugin_instance_name.empty()) {
+    plugin_instance_name = m->prefix + plugin_instance_name + m->suffix;
+  }
 }
 
 
diff --git a/src/user/user_model.cc b/src/user/user_model.cc
index 1a6bfbd7..afa3e251 100644
--- a/src/user/user_model.cc
+++ b/src/user/user_model.cc
@@ -341,6 +341,7 @@ mjCModel& mjCModel::operator+=(const mjCModel& other) {
     std::unordered_map<mjCPlugin*, mjCPlugin*> plugin_map;
     for (const auto& plugin : other.plugins_) {
       plugins_.push_back(new mjCPlugin(*plugin));
+      plugins_.back()->NameSpace(&other);
       plugin_map[plugin] = plugins_.back();
     }
     mapplugin(plugin_map, bodies_);
diff --git a/src/user/user_objects.cc b/src/user/user_objects.cc
index 833a8106..9b05702f 100644
--- a/src/user/user_objects.cc
+++ b/src/user/user_objects.cc
@@ -1016,6 +1016,9 @@ void mjCBody::NameSpace_(const mjCModel* m, bool propagate) {
   if (!classname.empty() && m != model) {
     classname = m->prefix + classname + m->suffix;
   }
+  if (!plugin_instance_name.empty()) {
+    plugin_instance_name = m->prefix + plugin_instance_name + m->suffix;
+  }
 
   for (auto& body : bodies) {
     body->prefix = m->prefix;
@@ -2222,6 +2225,9 @@ void mjCGeom::NameSpace(const mjCModel* m) {
   if (!spec_meshname_.empty() && model != m) {
     spec_meshname_ = m->prefix + spec_meshname_ + m->suffix;
   }
+  if (!plugin_instance_name.empty()) {
+    plugin_instance_name = m->prefix + plugin_instance_name + m->suffix;
+  }
 }
 
 
@@ -5649,6 +5655,9 @@ void mjCActuator::NameSpace(const mjCModel* m) {
   if (!name.empty()) {
     name = m->prefix + name + m->suffix;
   }
+  if (!plugin_instance_name.empty()) {
+    plugin_instance_name = m->prefix + plugin_instance_name + m->suffix;
+  }
   spec_target_ = m->prefix + spec_target_ + m->suffix;
   spec_refsite_ = m->prefix + spec_refsite_ + m->suffix;
   spec_slidersite_ = m->prefix + spec_slidersite_ + m->suffix;
@@ -5979,6 +5988,9 @@ void mjCSensor::NameSpace(const mjCModel* m) {
   if (!name.empty()) {
     name = m->prefix + name + m->suffix;
   }
+  if (!plugin_instance_name.empty()) {
+    plugin_instance_name = m->prefix + plugin_instance_name + m->suffix;
+  }
   prefix = m->prefix;
   suffix = m->suffix;
 }
@@ -6919,6 +6931,7 @@ mjCPlugin::mjCPlugin(mjCModel* _model) {
 
 mjCPlugin::mjCPlugin(const mjCPlugin& other) {
   *this = other;
+  id = -1;
 }
 
 
@@ -6934,6 +6947,15 @@ mjCPlugin& mjCPlugin::operator=(const mjCPlugin& other) {
 
 
 
+void mjCPlugin::NameSpace(const mjCModel* m) {
+  mjCBase::NameSpace(m);
+  if (!instance_name.empty()) {
+    instance_name = m->prefix + instance_name + m->suffix;
+  }
+}
+
+
+
 // compiler
 void mjCPlugin::Compile(void) {
   const mjpPlugin* plugin = mjp_getPluginAtSlot(spec.plugin_slot);
diff --git a/src/user/user_objects.h b/src/user/user_objects.h
index ea5b6f71..7a252133 100644
--- a/src/user/user_objects.h
+++ b/src/user/user_objects.h
@@ -1422,6 +1422,7 @@ class mjCPlugin : public mjCPlugin_ {
 
  private:
   void Compile(void);              // compiler
+  void NameSpace(const mjCModel* m);
 };
 
 
diff --git a/test/user/user_api_test.cc b/test/user/user_api_test.cc
index a4a7d425..123f6f73 100644
--- a/test/user/user_api_test.cc
+++ b/test/user/user_api_test.cc
@@ -243,10 +243,16 @@ TEST_F(PluginTest, AttachPlugin) {
   EXPECT_THAT(attachment_frame, NotNull());
 
   mjs_attachBody(attachment_frame, mjs_findBody(spec_2, "body"), "child-", "");
-  mjModel* model = mj_compile(spec_1, nullptr);
-  EXPECT_THAT(model, NotNull());
+  mjModel* model_1 = mj_compile(spec_1, nullptr);
+  EXPECT_THAT(model_1, NotNull());
 
-  mj_deleteModel(model);
+  // attach it a second time to test namespacing
+  mjs_attachBody(attachment_frame, mjs_findBody(spec_2, "body"), "copy-", "");
+  mjModel* model_2 = mj_compile(spec_1, nullptr);
+  EXPECT_THAT(model_2, NotNull());
+
+  mj_deleteModel(model_1);
+  mj_deleteModel(model_2);
   mj_deleteSpec(spec_1);
   mj_deleteSpec(spec_2);
 }