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

wasm/codegen/generated/bindings.cc

@@ -2331,6 +2331,12 @@ struct MjsCompiler {
   void set_alignfree(int value) {
     ptr_->alignfree = value;
   }
+  int conflict() const {
+    return ptr_->conflict;
+  }
+  void set_conflict(int value) {
+    ptr_->conflict = value;
+  }
   mjString meshdir() const {
     return (ptr_ && ptr_->meshdir) ? *(ptr_->meshdir) : "";
   }
@@ -11312,6 +11318,10 @@ EMSCRIPTEN_BINDINGS(mujoco_bindings) {
   enum_<mjtCone>("mjtCone")
     .value("mjCONE_PYRAMIDAL", mjCONE_PYRAMIDAL)
     .value("mjCONE_ELLIPTIC", mjCONE_ELLIPTIC);
+  enum_<mjtConflict>("mjtConflict")
+    .value("mjCONFLICT_WARNING", mjCONFLICT_WARNING)
+    .value("mjCONFLICT_MERGE", mjCONFLICT_MERGE)
+    .value("mjCONFLICT_ERROR", mjCONFLICT_ERROR);
   enum_<mjtConstraint>("mjtConstraint")
     .value("mjCNSTR_EQUALITY", mjCNSTR_EQUALITY)
     .value("mjCNSTR_FRICTION_DOF", mjCNSTR_FRICTION_DOF)
@@ -12993,6 +13003,7 @@ EMSCRIPTEN_BINDINGS(mujoco_bindings) {
     .property("balanceinertia", &MjsCompiler::balanceinertia, &MjsCompiler::set_balanceinertia, reference())
     .property("boundinertia", &MjsCompiler::boundinertia, &MjsCompiler::set_boundinertia, reference())
     .property("boundmass", &MjsCompiler::boundmass, &MjsCompiler::set_boundmass, reference())
+    .property("conflict", &MjsCompiler::conflict, &MjsCompiler::set_conflict, reference())
     .property("degree", &MjsCompiler::degree, &MjsCompiler::set_degree, reference())
     .property("discardvisual", &MjsCompiler::discardvisual, &MjsCompiler::set_discardvisual, reference())
     .property("eulerseq", &MjsCompiler::eulerseq)

wasm/tests/bindings_test.ts

@@ -1803,6 +1803,36 @@ describe('MuJoCo WASM Bindings', () => {
     }
   });
 
+  it('should compile a spec and emit warnings', () => {
+    const xml = `
+    <mujoco>
+      <worldbody>
+        <flexcomp name="test" type="grid" count="4 4 1" spacing=".2 .2 .2"
+                  dim="2" radius=".1"/>
+      </worldbody>
+    </mujoco>`;
+    let spec = null;
+    let model = null;
+    const warnSpy = spyOn(console, 'warn');
+    try {
+      spec = mujoco.parseXMLString(xml);
+      expect(spec).not.toBeNull();
+
+      model = mujoco.mj_compile(spec);
+      expect(model).not.toBeNull();
+      expect(warnSpy).toHaveBeenCalled();
+      const warningCall = warnSpy.calls.mostRecent();
+      expect(warningCall.args[0]).toContain("no equality constraints or passive forces");
+    } finally {
+      if (spec) {
+        spec.delete();
+      }
+      if (model) {
+        model.delete();
+      }
+    }
+  });
+
   it('should compile a spec from XML string with no assets', () => {
     let spec = null;
     let model = null;