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4dc33d6524
* ChatGPT-generated diamond virtual-inheritance test case.
* Report "virtual base at offset 0" but don't skip test.
* Remove Left/Right virtual default dtors, to resolve clang-tidy errors:
```
/__w/pybind11/pybind11/tests/test_class_sh_mi_thunks.cpp:44:13: error: prefer using 'override' or (rarely) 'final' instead of 'virtual' [modernize-use-override,-warnings-as-errors]
44 | virtual ~Left() = default;
| ~~~~~~~ ^
| override
/__w/pybind11/pybind11/tests/test_class_sh_mi_thunks.cpp:48:13: error: prefer using 'override' or (rarely) 'final' instead of 'virtual' [modernize-use-override,-warnings-as-errors]
48 | virtual ~Right() = default;
| ~~~~~~~ ^
| override
```
* Add assert(ptr) in register_instance_impl, deregister_instance_impl
* Proper bug fix
* Also exercise smart_holder_from_unique_ptr
* [skip ci] ChatGPT-generated bug fix: smart_holder::from_unique_ptr()
* Exception-safe ownership transfer from unique_ptr to shared_ptr
ChatGPT:
* shared_ptr’s ctor can throw (control-block alloc). Using get() keeps unique_ptr owning the memory if that happens, so no leak.
* Only after the shared_ptr is successfully constructed do you release(), transferring ownership exactly once.
* [skip ci] Rename alias_ptr to mi_subobject_ptr to distinguish from trampoline code (which often uses the term "alias", too)
* [skip ci] Also exercise smart_holder::from_raw_ptr_take_ownership
* [skip ci] Add st.first comments (generated by ChatGPT)
* [skip ci] Copy and extend (raw_ptr, unique_ptr) reproducer from PR #5796
* Some polishing: comments, add back Left/Right dtors for consistency within test_class_sh_mi_thunks.cpp
* explicitly default copy/move for VBase to silence -Wdeprecated-copy-with-dtor
* Resolve clang-tidy error:
```
/__w/pybind11/pybind11/tests/test_class_sh_mi_thunks.cpp:67:5: error: 'auto ptr' can be declared as 'auto *ptr' [readability-qualified-auto,-warnings-as-errors]
67 | auto ptr = new Diamond;
| ^~~~
| auto *
```
* Expand comment in `smart_holder::from_unique_ptr()`
* Better Left/Right padding to make it more likely that we avoid "all at offset 0". Clarify comment.
* Give up on `alignas(16)` to resolve MSVC warning:
```
"D:\a\pybind11\pybind11\build\ALL_BUILD.vcxproj" (default target) (1) ->
"D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj" (default target) (13) ->
(ClCompile target) ->
D:\a\pybind11\pybind11\tests\test_class_sh_mi_thunks.cpp(70,17): warning C4316: 'test_class_sh_mi_thunks::Diamond': object allocated on the heap may not be aligned 16 [D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj]
D:\a\pybind11\pybind11\tests\test_class_sh_mi_thunks.cpp(80,43): warning C4316: 'test_class_sh_mi_thunks::Diamond': object allocated on the heap may not be aligned 16 [D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\include\memory(2913,46): warning C4316: 'std::_Ref_count_obj2<_Ty>': object allocated on the heap may not be aligned 16 [D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\include\memory(2913,46): warning C4316: with [D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\include\memory(2913,46): warning C4316: [ [D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\include\memory(2913,46): warning C4316: _Ty=test_class_sh_mi_thunks::Diamond [D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\include\memory(2913,46): warning C4316: ] [D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj]
D:\a\pybind11\pybind11\include\pybind11\detail\init.h(77,21): warning C4316: 'test_class_sh_mi_thunks::Diamond': object allocated on the heap may not be aligned 16 [D:\a\pybind11\pybind11\build\tests\pybind11_tests.vcxproj]
```
The warning came from alignas(16) making Diamond over-aligned, while regular new/make_shared aren’t guaranteed to return 16-byte aligned memory on MSVC (hence C4316). I’ve removed the explicit alignment and switched to asymmetric payload sizes (char[4] vs char[24]), which still nudges MI layout without relying on over-alignment. This keeps the test goal and eliminates the warning across all MSVC builds. If we ever want to stress over-alignment explicitly, we can add aligned operator new/delete under __cpp_aligned_new, but that’s more than we need here.
* Rename test_virtual_base_at_offset_0() → test_virtual_base_not_at_offset_0() and replace pytest.skip() with assert. Add helpful comment for future maintainers.
105 lines
3.3 KiB
Python
105 lines
3.3 KiB
Python
from __future__ import annotations
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import pytest
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from pybind11_tests import class_sh_mi_thunks as m
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def test_ptrdiff_drvd_base0():
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ptrdiff = m.ptrdiff_drvd_base0()
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# A failure here does not (necessarily) mean that there is a bug, but that
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# test_class_sh_mi_thunks is not exercising what it is supposed to.
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# If this ever fails on some platforms: use pytest.skip()
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# If this ever fails on all platforms: don't know, seems extremely unlikely.
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assert ptrdiff != 0
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@pytest.mark.parametrize(
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"vec_size_fn",
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[
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m.vec_size_base0_raw_ptr,
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m.vec_size_base0_shared_ptr,
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],
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)
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@pytest.mark.parametrize(
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"get_fn",
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[
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m.get_drvd_as_base0_raw_ptr,
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m.get_drvd_as_base0_shared_ptr,
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m.get_drvd_as_base0_unique_ptr,
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],
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)
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def test_get_vec_size_raw_shared(get_fn, vec_size_fn):
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obj = get_fn()
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assert vec_size_fn(obj) == 5
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@pytest.mark.parametrize(
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"get_fn", [m.get_drvd_as_base0_raw_ptr, m.get_drvd_as_base0_unique_ptr]
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)
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def test_get_vec_size_unique(get_fn):
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obj = get_fn()
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assert m.vec_size_base0_unique_ptr(obj) == 5
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with pytest.raises(ValueError, match="Python instance was disowned"):
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m.vec_size_base0_unique_ptr(obj)
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def test_get_shared_vec_size_unique():
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obj = m.get_drvd_as_base0_shared_ptr()
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with pytest.raises(ValueError) as exc_info:
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m.vec_size_base0_unique_ptr(obj)
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assert (
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str(exc_info.value) == "Cannot disown external shared_ptr (load_as_unique_ptr)."
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)
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def test_virtual_base_not_at_offset_0():
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# This test ensures that the Diamond fixture actually exercises a non-zero
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# virtual-base subobject offset on our supported platforms/ABIs.
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#
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# If this assert ever fails on some platform/toolchain, please adjust the
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# C++ fixture so the virtual base is *not* at offset 0:
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# - Keep VBase non-empty.
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# - Make Left and Right non-empty and asymmetrically sized and, if
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# needed, nudge with a modest alignment.
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# - The goal is to achieve a non-zero address delta between `Diamond*`
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# and `static_cast<VBase*>(Diamond*)`.
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#
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# Rationale: certain smart_holder features are exercised only when the
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# registered subobject address differs from the most-derived object start,
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# so this check guards test efficacy across compilers.
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addrs = m.diamond_addrs()
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assert addrs.as_vbase - addrs.as_self != 0, (
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"Diamond VBase at offset 0 on this platform; to ensure test efficacy, "
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"tweak fixtures (VBase/Left/Right) to ensure non-zero subobject offset."
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)
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@pytest.mark.parametrize(
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"make_fn",
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[
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m.make_diamond_as_vbase_raw_ptr, # exercises smart_holder::from_raw_ptr_take_ownership
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m.make_diamond_as_vbase_shared_ptr, # exercises smart_holder_from_shared_ptr
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m.make_diamond_as_vbase_unique_ptr, # exercises smart_holder_from_unique_ptr
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],
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)
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def test_make_diamond_as_vbase(make_fn):
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# Added under PR #5836
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vb = make_fn()
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assert vb.ping() == 7
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@pytest.mark.parametrize(
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"clone_fn",
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[
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m.Tiger.clone_raw_ptr,
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m.Tiger.clone_shared_ptr,
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m.Tiger.clone_unique_ptr,
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],
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)
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def test_animal_cat_tiger(clone_fn):
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# Based on Animal-Cat-Tiger reproducer under PR #5796
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tiger = m.Tiger()
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cloned = clone_fn(tiger)
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assert isinstance(cloned, m.Tiger)
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