Add policies for global attribute conflict resolution upon attach

For example when loading parent_merge.xml: ``` WARNING: Attach conflict when attaching 'child' to 'parent_merge', policy is 'merge' timestep: parent has 0.005, child has 0.002, taking the minimum iterations: parent has 50, child has 100, taking the maximum flag 'Damper': added from child ``` When loading parent_error.xml: ``` XML Error: Attach conflict when attaching 'child' to 'parent_error', policy is 'error' timestep: parent has 0.005, child has 0.002 iterations: parent has 50, child has 100 Element 'attach', line 10 ``` PiperOrigin-RevId: 933620810 Change-Id: Ib477863b5ef763474d27fb4be5a4148be1d5d500
2026-06-17 03:34:10 -07:00
parent 30357c38a3
commit 410c73168c
37 changed files with 2705 additions and 449 deletions
@@ -3897,5 +3897,80 @@ TEST_F(ActuatorParseTest, DampingArmatureDefaultsPropagate) {
  mj_deleteModel(model);
 }

+TEST_F(XMLReaderTest, AttachConflictXMLWarning) {
+  mock_warning_handler.ExpectWarnings();
+  std::array<char, 1024> error;
+  std::string path = GetTestDataFilePath("xml/testdata/parent_warn.xml");
+  mjSpec* spec = mj_parseXML(path.c_str(), nullptr, error.data(), error.size());
+  ASSERT_THAT(spec, NotNull()) << error.data();
+
+  // one grouped warning per attach, containing gravity and damper flag
+  // (constraint is only authored by child, not a conflict)
+  EXPECT_EQ(mjs_numWarnings(spec), 1);
+  std::string w = mjs_getWarning(spec, 0);
+  EXPECT_THAT(w, HasSubstr("gravity: parent has 0 0 -10, child has 0 0 0,"
+                           " keeping parent value"));
+  EXPECT_THAT(w, HasSubstr("flag 'Damper'"));
+
+  mjModel* m = mj_compile(spec, nullptr);
+  ASSERT_THAT(m, NotNull());
+  // Gravity should be parent's value (0 0 -10)
+  EXPECT_MJTNUM_EQ(m->opt.gravity[0], 0);
+  EXPECT_MJTNUM_EQ(m->opt.gravity[1], 0);
+  EXPECT_MJTNUM_EQ(m->opt.gravity[2], -10);
+
+  mj_deleteModel(m);
+  mj_deleteSpec(spec);
+}
+
+TEST_F(XMLReaderTest, AttachConflictXMLMerge) {
+  mock_warning_handler.ExpectWarnings();
+  std::array<char, 1024> error;
+  std::string path = GetTestDataFilePath("xml/testdata/parent_merge.xml");
+  mjSpec* spec = mj_parseXML(path.c_str(), nullptr, error.data(), error.size());
+  ASSERT_THAT(spec, NotNull()) << error.data();
+
+  // one grouped warning per attach, containing timestep, iterations, and flag
+  EXPECT_GE(mjs_numWarnings(spec), 1);
+  std::string w = mjs_getWarning(spec, 0);
+  EXPECT_THAT(w, HasSubstr("timestep: parent has 0.005, child has 0.002,"
+                           " taking the minimum"));
+  EXPECT_THAT(w, HasSubstr("iterations: parent has 50, child has 100,"
+                           " taking the maximum"));
+
+  mjModel* m = mj_compile(spec, nullptr);
+  ASSERT_THAT(m, NotNull());
+  // Timestep should be min (0.002)
+  EXPECT_MJTNUM_EQ(m->opt.timestep, 0.002);
+  // Iterations should be max (100)
+  EXPECT_EQ(m->opt.iterations, 100);
+
+  mj_deleteModel(m);
+  mj_deleteSpec(spec);
+}
+
+TEST_F(XMLReaderTest, AttachConflictXMLError) {
+  std::array<char, 1024> error;
+  std::string path = GetTestDataFilePath("xml/testdata/parent_error.xml");
+  mjSpec* spec = mj_parseXML(path.c_str(), nullptr, error.data(), error.size());
+
+  // Should fail to parse because of conflict in timestep in error mode
+  EXPECT_THAT(spec, IsNull());
+  EXPECT_THAT(error.data(),
+              HasSubstr("timestep: parent has 0.005, child has 0.002"));
+}
+
+TEST_F(XMLReaderTest, AttachConflictXMLMergeUnmergableError) {
+  std::array<char, 1024> error;
+  std::string path =
+      GetTestDataFilePath("xml/testdata/parent_merge_unmergable.xml");
+  mjSpec* spec = mj_parseXML(path.c_str(), nullptr, error.data(), error.size());
+
+  // Should fail to parse because gravity is unmergeable in merge mode
+  EXPECT_THAT(spec, IsNull());
+  EXPECT_THAT(error.data(),
+              HasSubstr("gravity: parent has 0 0 -10, child has 0 0 0"));
+}
+
 }  // namespace
 }  // namespace mujoco