Throw an error if multiple orientation specifiers are used in the same element.

- Applies to [orientation specifiers](https://mujoco.readthedocs.io/en/latest/modeling.html#frame-orientations) in `body`, `inertial`, `geom`, `site`, `camera`.
- Before this change the check was done only for multiple *alternative* specifiers, but not for `quat` and an alternative specifier.
- Moved the check from the compiler to the parser.
- Added tests.

PiperOrigin-RevId: 453201981
Change-Id: I20907361f211dae904e734cd083e9df0efe4f654

src/user/user_objects.cc

@@ -120,16 +120,6 @@ mjCAlternative::mjCAlternative() {
 // used for geom, site, body and camera frames
 const char* mjCAlternative::Set(double* quat, double* inertia,
                                 bool degree, const char* sequence) {
-  // check for multiple defitions
-  int ndef = (int)mjuu_defined(axisangle[0]) +
-             (int)mjuu_defined(xyaxes[0]) +
-             (int)mjuu_defined(zaxis[0]) +
-             (int)mjuu_defined(euler[0]) +
-             (int)mjuu_defined(fullinertia[0]);
-  if (ndef>1) {
-    return "too many alternative definitions";
-  }
-
   // set quat using axisangle
   if (mjuu_defined(axisangle[0])) {
     // convert to radians if necessary, normalize axis

src/xml/xml_base.cc

@@ -52,9 +52,12 @@ void mjXBase::SetModel(mjCModel* _model) {
 // read alternative orientation specification
 void mjXBase::ReadAlternative(XMLElement* elem, mjCAlternative& alt) {
   string text;
-  ReadAttr(elem, "axisangle", 4, alt.axisangle, text);
-  ReadAttr(elem, "xyaxes", 6, alt.xyaxes, text);
-  ReadAttr(elem, "zaxis", 3, alt.zaxis, text);
-  ReadAttr(elem, "euler", 3, alt.euler, text);
-  ReadAttr(elem, "fullinertia", 6, alt.fullinertia, text);
+  int read = (int)(elem->Attribute("quat") != 0) +
+             (ReadAttr(elem, "axisangle", 4, alt.axisangle, text) ? 1 : 0) +
+             (ReadAttr(elem, "xyaxes", 6, alt.xyaxes, text) ? 1 : 0) +
+             (ReadAttr(elem, "zaxis", 3, alt.zaxis, text) ? 1 : 0) +
+             (ReadAttr(elem, "euler", 3, alt.euler, text) ? 1 : 0) +
+             (ReadAttr(elem, "fullinertia", 6, alt.fullinertia, text) ? 1 : 0);
+  if (read > 1)
+    throw mjXError(elem, "multiple orientation specifiers for the same field are not allowed");
 }

src/xml/xml_native_reader.cc

@@ -1120,9 +1120,9 @@ void mjXReader::OneGeom(XMLElement* elem, mjCGeom* pgeom) {
   ReadAttr(elem, "mass", 1, &pgeom->_mass, text);
   ReadAttr(elem, "density", 1, &pgeom->density, text);
   ReadAttr(elem, "fromto", 6, pgeom->fromto, text);
-  ReadAlternative(elem, pgeom->alt);
   ReadAttr(elem, "pos", 3, pgeom->pos, text);
   ReadAttr(elem, "quat", 4, pgeom->quat, text);
+  ReadAlternative(elem, pgeom->alt);
 
   GetXMLPos(elem, pgeom);
 }

test/xml/xml_native_reader_test.cc

@@ -192,6 +192,49 @@ TEST_F(UserDataTest, AllowsSpaces) {
   mj_deleteModel(model);
 }
 
+TEST_F(UserDataTest, InvalidDoubleOrientation) {
+  std::string prefix = "<mujoco><worldbody><";
+  std::string suffix = "/></worldbody></mujoco>";
+  std::vector<std::string> orientations = {
+    R"( quat="0 1 0 0" )",
+    R"( euler="1.7 2.9 0.1" )",
+    R"( zaxis="1.7 2.9 0.1" )",
+    R"( axisangle="1.7 2.9 0.1 0" )",
+    R"( xyaxes="1.7 2.9 0.1 0.4 1.4 0.6" )",
+  };
+  std::vector<std::string> fields = {
+    "geom", "body", "camera", "site"
+  };
+  for (auto const& field : fields) {
+    for (auto const& orient1 : orientations) {
+      for (auto const& orient2 : orientations) {
+        if (orient1 == orient2) continue;
+        std::string xml = prefix + field + orient1 + orient2 + suffix;
+        std::array<char, 1024> error;
+        mjModel* model = LoadModelFromString(xml.c_str(), error.data(), error.size());
+        ASSERT_THAT(model, IsNull());
+        EXPECT_THAT(error.data(), HasSubstr("multiple orientation specifiers for the same field"));
+      }
+    }
+  }
+}
+
+TEST_F(UserDataTest, InvalidInertialOrientation) {
+  static constexpr char xml[] = R"(
+  <mujoco>
+    <worldbody>
+      <body>
+        <inertial pos="0 0 0" mass="1" quat="1 0 0 0" fullinertia="1 1 1 0 0 0"/>
+      </body>
+    </worldbody>
+  </mujoco>
+  )";
+  std::array<char, 1024> error;
+  mjModel* model = LoadModelFromString(xml, error.data(), error.size());
+  ASSERT_THAT(model, IsNull());
+  EXPECT_THAT(error.data(), HasSubstr("multiple orientation specifiers for the same field"));
+}
+
 // ------------- test relative frame sensor parsing ----------------------------
 
 using RelativeFrameSensorParsingTest = MujocoTest;