Fix --gen-compare to not generate comparators for native types. (#8681)

Per the definition of --gen-compare: only generate comparators for object API
generated structs. Types annoated with native_type must define their own
comparators if `--gen-compare` is enabled.

Also enables --gen-compare for native_type_test and fixes the test by adding a
comparator for the Native::Vector3D type.

CMakeLists.txt

@@ -537,14 +537,13 @@ if(FLATBUFFERS_BUILD_TESTS)
   add_definitions(-DFLATBUFFERS_TEST_PATH_PREFIX=${CMAKE_CURRENT_SOURCE_DIR}/)
 
   # The flattest target needs some generated files
-  SET(FLATC_OPT --cpp --gen-mutable --gen-object-api --reflect-names)
+  SET(FLATC_OPT_COMP --cpp --gen-compare --gen-mutable --gen-object-api --reflect-names)
-  SET(FLATC_OPT_COMP ${FLATC_OPT};--gen-compare)
   SET(FLATC_OPT_SCOPED_ENUMS ${FLATC_OPT_COMP};--scoped-enums)
 
   compile_schema_for_test(tests/alignment_test.fbs "${FLATC_OPT_COMP}")
   compile_schema_for_test(tests/arrays_test.fbs "${FLATC_OPT_SCOPED_ENUMS}")
   compile_schema_for_test(tests/native_inline_table_test.fbs "${FLATC_OPT_COMP}")
-  compile_schema_for_test(tests/native_type_test.fbs "${FLATC_OPT}")
+  compile_schema_for_test(tests/native_type_test.fbs "${FLATC_OPT_COMP}")
   compile_schema_for_test(tests/key_field/key_field_sample.fbs "${FLATC_OPT_COMP}")
   compile_schema_for_test(tests/64bit/test_64bit.fbs "${FLATC_OPT_COMP};--bfbs-gen-embed")
   compile_schema_for_test(tests/64bit/evolution/v1.fbs "${FLATC_OPT_COMP}")

scripts/generate_code.py

@@ -355,7 +355,7 @@ flatc(
 )
 
 flatc(
-    ["--cpp", "--gen-mutable", "--gen-object-api", "--reflect-names"],
+    ["--cpp", "--gen-compare", "--gen-mutable", "--gen-object-api", "--reflect-names"],
     schema="native_type_test.fbs",
 )
 

src/idl_gen_cpp.cpp

@@ -512,7 +512,8 @@ class CppGenerator : public BaseGenerator {
     // Generate forward declarations for all equal operators
     if (opts_.generate_object_based_api && opts_.gen_compare) {
       for (const auto& struct_def : parser_.structs_.vec) {
-        if (!struct_def->generated) {
+        const auto native_type = struct_def->attributes.Lookup("native_type");
+        if (!struct_def->generated && !native_type) {
           SetNameSpace(struct_def->defined_namespace);
           auto nativeName = NativeName(Name(*struct_def), struct_def, opts_);
           code_ += "bool operator==(const " + nativeName + " &lhs, const " +
@@ -2190,6 +2191,12 @@ class CppGenerator : public BaseGenerator {
 
   void GenCompareOperator(const StructDef& struct_def,
                           const std::string& accessSuffix = "") {
+    // Do not generate compare operators for native types.
+    const auto native_type = struct_def.attributes.Lookup("native_type");
+    if (native_type) {
+      return;
+    }
+
     std::string compare_op;
     for (auto it = struct_def.fields.vec.begin();
          it != struct_def.fields.vec.end(); ++it) {

tests/native_type_test_generated.h

@@ -29,6 +29,11 @@ struct ApplicationData;
 struct ApplicationDataBuilder;
 struct ApplicationDataT;
 
+bool operator==(const MatrixT &lhs, const MatrixT &rhs);
+bool operator!=(const MatrixT &lhs, const MatrixT &rhs);
+bool operator==(const ApplicationDataT &lhs, const ApplicationDataT &rhs);
+bool operator!=(const ApplicationDataT &lhs, const ApplicationDataT &rhs);
+
 inline const ::flatbuffers::TypeTable *Vector3DTypeTable();
 
 inline const ::flatbuffers::TypeTable *Vector3DAltTypeTable();
@@ -377,6 +382,19 @@ inline ::flatbuffers::Offset<ApplicationData> CreateApplicationDataDirect(
 
 ::flatbuffers::Offset<ApplicationData> CreateApplicationData(::flatbuffers::FlatBufferBuilder &_fbb, const ApplicationDataT *_o, const ::flatbuffers::rehasher_function_t *_rehasher = nullptr);
 
+
+inline bool operator==(const MatrixT &lhs, const MatrixT &rhs) {
+  return
+      (lhs.rows == rhs.rows) &&
+      (lhs.columns == rhs.columns) &&
+      (lhs.values == rhs.values);
+}
+
+inline bool operator!=(const MatrixT &lhs, const MatrixT &rhs) {
+    return !(lhs == rhs);
+}
+
+
 inline MatrixT *Matrix::UnPack(const ::flatbuffers::resolver_function_t *_resolver) const {
   auto _o = std::unique_ptr<MatrixT>(new MatrixT());
   UnPackTo(_o.get(), _resolver);
@@ -409,6 +427,22 @@ inline ::flatbuffers::Offset<Matrix> Matrix::Pack(::flatbuffers::FlatBufferBuild
       _values);
 }
 
+
+inline bool operator==(const ApplicationDataT &lhs, const ApplicationDataT &rhs) {
+  return
+      (lhs.vectors == rhs.vectors) &&
+      (lhs.vectors_alt == rhs.vectors_alt) &&
+      ((lhs.position == rhs.position) || (lhs.position && rhs.position && *lhs.position == *rhs.position)) &&
+      (lhs.position_inline == rhs.position_inline) &&
+      ((lhs.matrix == rhs.matrix) || (lhs.matrix && rhs.matrix && *lhs.matrix == *rhs.matrix)) &&
+      (lhs.matrices.size() == rhs.matrices.size() && std::equal(lhs.matrices.cbegin(), lhs.matrices.cend(), rhs.matrices.cbegin(), [](std::unique_ptr<Geometry::MatrixT> const &a, std::unique_ptr<Geometry::MatrixT> const &b) { return (a == b) || (a && b && *a == *b); }));
+}
+
+inline bool operator!=(const ApplicationDataT &lhs, const ApplicationDataT &rhs) {
+    return !(lhs == rhs);
+}
+
+
 inline ApplicationDataT::ApplicationDataT(const ApplicationDataT &o)
       : vectors(o.vectors),
         vectors_alt(o.vectors_alt),

tests/native_type_test_impl.h

@@ -17,6 +17,10 @@ struct Vector3D {
     this->y = _y;
     this->z = _z;
   }
+
+  bool operator==(const Vector3D &other) const {
+    return (x == other.x) && (y == other.y) && (z == other.z);
+  }
 };
 }  // namespace Native