Failing unit test for #7516

CMakeLists.txt

@@ -230,6 +230,8 @@ set(FlatBuffers_Tests_SRCS
   tests/util_test.cpp
   tests/native_type_test_impl.h
   tests/native_type_test_impl.cpp
+  tests/alignment_test.h
+  tests/alignment_test.cpp
   include/flatbuffers/code_generators.h
   src/code_generators.cpp
   # file generate by running compiler on tests/monster_test.fbs
@@ -251,6 +253,8 @@ set(FlatBuffers_Tests_SRCS
   ${CMAKE_CURRENT_BINARY_DIR}/tests/optional_scalars_generated.h
   # file generate by running compiler on tests/native_inline_table_test.fbs
   ${CMAKE_CURRENT_BINARY_DIR}/tests/native_inline_table_test_generated.h
+  # file generate by running compiler on tests/alignment_test.fbs
+  ${CMAKE_CURRENT_BINARY_DIR}/tests/alignment_test_generated.h
 )
 
 set(FlatBuffers_Tests_CPP17_SRCS
@@ -623,6 +627,7 @@ if(FLATBUFFERS_BUILD_TESTS)
   compile_flatbuffers_schema_to_binary(tests/arrays_test.fbs)
   compile_flatbuffers_schema_to_embedded_binary(tests/monster_test.fbs "--no-includes;--gen-compare")
   compile_flatbuffers_schema_to_cpp(tests/native_inline_table_test.fbs "--gen-compare")
+  compile_flatbuffers_schema_to_cpp(tests/alignment_test.fbs "--gen-compare")
   if(NOT (MSVC AND (MSVC_VERSION LESS 1900)))
     compile_flatbuffers_schema_to_cpp(tests/monster_extra.fbs) # Test floating-point NAN/INF.
   endif()

tests/alignment_test.cpp

@@ -0,0 +1,31 @@
+#include "alignment_test.h"
+
+#include "flatbuffers/flatbuffer_builder.h"
+#include "alignment_test_generated.h"
+#include "test_assert.h"
+
+namespace flatbuffers {
+namespace tests {
+
+void AlignmentTest() {
+  FlatBufferBuilder builder;
+
+  BadAlignmentLarge large;
+  Offset<OuterLarge> outer_large = CreateOuterLarge(builder, &large);
+
+  BadAlignmentSmall *small;
+  Offset<Vector<const BadAlignmentSmall *>> small_offset =
+      builder.CreateUninitializedVectorOfStructs(9, &small);
+  (void)small; // We do not have to write data to trigger the test failure
+
+  Offset<BadAlignmentRoot> root =
+      CreateBadAlignmentRoot(builder, outer_large, small_offset);
+
+  builder.Finish(root);
+
+  Verifier verifier(builder.GetBufferPointer(), builder.GetSize());
+  TEST_ASSERT(VerifyBadAlignmentRootBuffer(verifier));
+}
+
+}  // namespace tests
+}  // namespace flatbuffers

tests/alignment_test.fbs

@@ -0,0 +1,24 @@
+// sizeof(BadAlignmentSmall) == 12
+// alignof(BadAlignmentSmall) == 4
+struct BadAlignmentSmall {
+  var_0: uint;
+  var_1: uint;
+  var_2: uint;
+}
+
+// sizeof(BadAlignmentLarge) == 8
+// alignof(BadAlignmentLarge) == 8
+struct BadAlignmentLarge {
+  var_0: ulong;
+}
+
+table OuterLarge {
+  large: BadAlignmentLarge;
+}
+
+table BadAlignmentRoot {
+  large: OuterLarge;
+  small: [BadAlignmentSmall];
+}
+
+root_type BadAlignmentRoot;

tests/alignment_test.h

@@ -0,0 +1,12 @@
+#ifndef TESTS_ALIGNMENT_TEST_H
+#define TESTS_ALIGNMENT_TEST_H
+
+namespace flatbuffers {
+namespace tests {
+
+void AlignmentTest();
+
+}  // namespace tests
+}  // namespace flatbuffers
+
+#endif

tests/test.cpp

@@ -20,6 +20,7 @@
 #include <string>
 
 #include "evolution_test.h"
+#include "alignment_test.h"
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/minireflect.h"
@@ -1415,6 +1416,8 @@ int FlatBufferTests(const std::string &tests_data_path) {
 
   SizePrefixedTest();
 
+  AlignmentTest();
+
 #ifndef FLATBUFFERS_NO_FILE_TESTS
   ParseAndGenerateTextTest(tests_data_path, false);
   ParseAndGenerateTextTest(tests_data_path, true);