Add mju_getXMLDependencies that given an MJCF file returns filepaths to all of it's dependencies.

PiperOrigin-RevId: 814203235
Change-Id: Ib5c2e2f4dd42224a768c88d76473544190c72bc0

test/xml/CMakeLists.txt

@@ -16,6 +16,8 @@ mujoco_test(xml_api_test)
 
 mujoco_test(xml_native_reader_test)
 
+mujoco_test(xml_utils_test)
+
 mujoco_test(
   xml_native_writer_test
   ADDITIONAL_LINK_LIBRARIES

test/xml/testdata/many_dependencies.xml

@@ -0,0 +1,21 @@
+<mujoco>
+  <include file="child.xml"/>
+
+  <compiler meshdir="meshes"/>
+  <asset>
+    <model name="other" file="parent_model.xml"/>
+    <mesh name="mesh1" file="mesh1.obj"/>
+  </asset>
+  <worldbody>
+    <body name="my_parent">
+      <geom name="my_geom" size="2"/>
+      <flexcomp type="mesh" file="flex.obj" name="flex" rigid="true"/>
+    </body>
+    <body name="box">
+      <geom type="box" mesh="mesh1"/>
+    </body>
+  </worldbody>
+  <deformable>
+    <skin name="skin" file="cube.skn"/>
+  </deformable>
+</mujoco>

test/xml/testdata/meshes/flex.obj

@@ -0,0 +1,39 @@
+# Simple Cube - OBJ File
+
+# Vertices (v)
+# 8 corners of the cube
+
+# Back Face
+v -1.0 -1.0 -1.0
+v  1.0 -1.0 -1.0
+v  1.0  1.0 -1.0
+v -1.0  1.0 -1.0
+
+# Front Face
+v -1.0 -1.0  1.0
+v  1.0 -1.0  1.0
+v  1.0  1.0  1.0
+v -1.0  1.0  1.0
+
+# Faces (f)
+# A cube has 6 faces. Each face is a quad, defined by 4 vertices.
+# The vertices are numbered according to their order of appearance above, starting from 1.
+# The order defines the face normal (front-facing) based on the right-hand rule.
+
+# Back Face (v1, v2, v3, v4)
+f 1 2 3 4
+
+# Right Face (v2, v6, v7, v3)
+f 2 6 7 3
+
+# Front Face (v5, v8, v7, v6) - Note the ordering for correct normal
+f 5 8 7 6
+
+# Left Face (v1, v4, v8, v5)
+f 1 4 8 5
+
+# Top Face (v4, v3, v7, v8)
+f 4 3 7 8
+
+# Bottom Face (v1, v5, v6, v2)
+f 1 5 6 2

test/xml/testdata/meshes/mesh1.obj

@@ -0,0 +1,39 @@
+# Simple Cube - OBJ File
+
+# Vertices (v)
+# 8 corners of the cube
+
+# Back Face
+v -1.0 -1.0 -1.0
+v  1.0 -1.0 -1.0
+v  1.0  1.0 -1.0
+v -1.0  1.0 -1.0
+
+# Front Face
+v -1.0 -1.0  1.0
+v  1.0 -1.0  1.0
+v  1.0  1.0  1.0
+v -1.0  1.0  1.0
+
+# Faces (f)
+# A cube has 6 faces. Each face is a quad, defined by 4 vertices.
+# The vertices are numbered according to their order of appearance above, starting from 1.
+# The order defines the face normal (front-facing) based on the right-hand rule.
+
+# Back Face (v1, v2, v3, v4)
+f 1 2 3 4
+
+# Right Face (v2, v6, v7, v3)
+f 2 6 7 3
+
+# Front Face (v5, v8, v7, v6) - Note the ordering for correct normal
+f 5 8 7 6
+
+# Left Face (v1, v4, v8, v5)
+f 1 4 8 5
+
+# Top Face (v4, v3, v7, v8)
+f 4 3 7 8
+
+# Bottom Face (v1, v5, v6, v2)
+f 1 5 6 2

test/xml/testdata/parent_model.xml

@@ -0,0 +1,11 @@
+<mujoco>
+  <asset>
+    <model name="other" file="child.xml"/>
+  </asset>
+  <worldbody>
+    <body name="parent">
+      <geom name="geom" size="2"/>
+      <attach model="other" body="body" prefix="other"/>
+    </body>
+  </worldbody>
+</mujoco>

test/xml/xml_native_writer_test.cc

@@ -1388,6 +1388,7 @@ TEST_F(XMLWriterTest, WriteReadCompare) {
             // exclude files that fail the comparison test
             absl::StrContains(p.path().string(), "tactile") ||
             absl::StrContains(p.path().string(), "makemesh") ||
+            absl::StrContains(p.path().string(), "many_dependencies") ||
             absl::StrContains(p.path().string(), "usd") ||
             absl::StrContains(p.path().string(), "torus_maxhull") ||
             absl::StrContains(p.path().string(), "fitmesh_") ||

test/xml/xml_utils_test.cc

@@ -0,0 +1,46 @@
+// Copyright 2025 DeepMind Technologies Limited
+//
+// 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.
+
+
+#include <set>
+#include <string>
+#include <vector>
+
+#include <gtest/gtest.h>
+#include <mujoco/mujoco.h>
+#include "test/fixture.h"
+
+namespace mujoco {
+namespace {
+
+TEST_F(MujocoTest, GetXMLDependenciesTest) {
+  static const std::vector<std::string> kModelPaths = {
+      GetTestDataFilePath("xml/testdata/many_dependencies.xml"),
+      GetTestDataFilePath("xml/testdata/parent_model.xml"),
+      GetTestDataFilePath("xml/testdata/child.xml"),
+      GetTestDataFilePath("xml/testdata/meshes/mesh1.obj"),
+      GetTestDataFilePath("xml/testdata/meshes/flex.obj"),
+      GetTestDataFilePath("xml/testdata/meshes/cube.skn"),
+  };
+
+  mjStringVec dependencies;
+  mju_getXMLDependencies(kModelPaths[0].c_str(), &dependencies);
+  std::set<std::string> dependency_set{dependencies.begin(),
+                                       dependencies.end()};
+  std::set<std::string> expected_dependency_set{kModelPaths.begin(),
+                                                kModelPaths.end()};
+  EXPECT_EQ(dependency_set, expected_dependency_set);
+}
+}  // namespace
+}  // namespace mujoco