pybind11/include
Ralf W. Grosse-Kunstleve 55105fbeaf
[smart_holder] Bug fix: std::unique_ptr deleter needs to be copied. (#4850)
* Store `std::function<void (void *)>` del_fun; in `guarded_delete`

* Specialize the simple common case.

Using a `union` is complicated: https://en.cppreference.com/w/cpp/language/union

> If members of a union are classes with user-defined constructors and destructors, to switch the active member, explicit destructor and placement new are generally needed:

Using `std::variant` increases compile-time overhead.

It is currently unclear how much these effects matter in practice: optimization left for later.

* Add one test case (more later).

* Add `const` to resolve clang-tidy error.

```
-- The CXX compiler identification is Clang 15.0.7

/usr/bin/cmake -E __run_co_compile --tidy="/usr/bin/clang-tidy;--use-color;--warnings-as-errors=*;--extra-arg-before=--driver-mode=g++" --source=/__w/pybind11/pybind11/tests/test_class_sh_inheritance.cpp -- /usr/bin/c++ -DPYBIND11_ENABLE_TYPE_CASTER_ODR_GUARD_IF_AVAILABLE -DPYBIND11_TEST_EIGEN -Dpybind11_tests_EXPORTS -I/__w/pybind11/pybind11/include -isystem /usr/include/python3.9 -isystem /__w/pybind11/pybind11/build/_deps/eigen-src -Os -DNDEBUG -fPIC -fvisibility=hidden -Wall -Wextra -Wconversion -Wcast-qual -Wdeprecated -Wundef -Wnon-virtual-dtor -flto=thin -std=c++17 -o CMakeFiles/pybind11_tests.dir/test_class_sh_inheritance.cpp.o -c /__w/pybind11/pybind11/tests/test_class_sh_inheritance.cpp
/__w/pybind11/pybind11/tests/pure_cpp/smart_holder_poc_test.cpp:264:30: error: pointer parameter 'raw_ptr' can be pointer to const [readability-non-const-parameter,-warnings-as-errors]
        new int(19), [](int *raw_ptr) { delete raw_ptr; });
                             ^
                        const
```

* Introduce `struct custom_deleter` to ensure the deleter is moved as desired (the lambda function only captures a reference, which can become dangling).

* Resolve helpful clang-tidy errors.

```
/usr/bin/cmake -E __run_co_compile --tidy="/usr/bin/clang-tidy;--use-color;--warnings-as-errors=*;--extra-arg-before=--driver-mode=g++" --source=/__w/pybind11/pybind11/tests/test_class.cpp -- /usr/bin/c++ -DPYBIND11_ENABLE_TYPE_CASTER_ODR_GUARD_IF_AVAILABLE -DPYBIND11_TEST_EIGEN -Dpybind11_tests_EXPORTS -I/__w/pybind11/pybind11/include -isystem /usr/include/python3.9 -isystem /__w/pybind11/pybind11/build/_deps/eigen-src -Os -DNDEBUG -fPIC -fvisibility=hidden -Wall -Wextra -Wconversion -Wcast-qual -Wdeprecated -Wundef -Wnon-virtual-dtor -flto=thin -std=c++17 -o CMakeFiles/pybind11_tests.dir/test_class.cpp.o -c /__w/pybind11/pybind11/tests/test_class.cpp
/__w/pybind11/pybind11/include/pybind11/detail/smart_holder_poc.h:114:5: error: single-argument constructors must be marked explicit to avoid unintentional implicit conversions [google-explicit-constructor,-warnings-as-errors]
    custom_deleter(D &&deleter) : deleter{std::move(deleter)} {}
    ^
    explicit
/__w/pybind11/pybind11/include/pybind11/detail/smart_holder_poc.h:120:76: error: forwarding reference passed to std::move(), which may unexpectedly cause lvalues to be moved; use std::forward() instead [bugprone-move-forwarding-reference,-warnings-as-errors]
    return guarded_delete(std::function<void(void *)>(custom_deleter<T, D>(std::move(uqp_del))),
                                                                           ^~~~~~~~~
                                                                           std::forward<D>
```

* Workaround for gcc 4.8.5, clang 3.6

* Transfer reduced test here.

Reduced from a PyCLIF use case in the wild by @wangxf123456 (internal change cl/565476030).

* Add missing include (clangd Include Cleaner)

* Change `std::move` to `std::forward` as suggested by @iwanders.

* Add missing includes (clangd Include Cleaner)

* Use new `PYBIND11_TESTS_PURE_CPP_SMART_HOLDER_POC_TEST_CPP` to exclude `smart_holder::as_unique_ptr` method from production code.

* Systematically add `PYBIND11_TESTS_PURE_CPP_SMART_HOLDER_POC_TEST_CPP` to mark code that is not used from production code. Add comment to explain.

* Very simple experiment related to https://github.com/pybind/pybind11/pull/4850#issuecomment-1789780676

Does the `PYBIND11_TESTS_PURE_CPP_SMART_HOLDER_POC_TEST_CPP` define have anything to do with it?

* Revert "Very simple experiment related to https://github.com/pybind/pybind11/pull/4850#issuecomment-1789780676"

This reverts commit fe59369f40.
2023-11-02 08:21:13 -07:00
..
pybind11 [smart_holder] Bug fix: std::unique_ptr deleter needs to be copied. (#4850) 2023-11-02 08:21:13 -07:00