fix: enable py::implicitly_convertible<py::none, ...> for py::class_-wrapped types (#3059)

* Allow casting from None to a custom object, closes #2778

* ci.yml patch from the smart_holder branch for full CI coverage.
This commit is contained in:
Cris Luengo 2021-06-25 18:56:17 -06:00 committed by GitHub
parent 484b0f0433
commit 93e69191c1
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4 changed files with 55 additions and 20 deletions

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@ -100,7 +100,7 @@ jobs:
run: >
cmake -S . -B .
-DPYBIND11_WERROR=ON
-DDOWNLOAD_CATCH=ON
-DDOWNLOAD_CATCH=OFF
-DDOWNLOAD_EIGEN=ON
-DCMAKE_CXX_STANDARD=11
${{ matrix.args }}
@ -111,10 +111,10 @@ jobs:
- name: Python tests C++11
run: cmake --build . --target pytest -j 2
- name: C++11 tests
# TODO: Figure out how to load the DLL on Python 3.8+
if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10-dev'))"
run: cmake --build . --target cpptest -j 2
#- name: C++11 tests
# # TODO: Figure out how to load the DLL on Python 3.8+
# if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10-dev'))"
# run: cmake --build . --target cpptest -j 2
- name: Interface test C++11
run: cmake --build . --target test_cmake_build
@ -127,7 +127,7 @@ jobs:
run: >
cmake -S . -B build2
-DPYBIND11_WERROR=ON
-DDOWNLOAD_CATCH=ON
-DDOWNLOAD_CATCH=OFF
-DDOWNLOAD_EIGEN=ON
-DCMAKE_CXX_STANDARD=17
${{ matrix.args }}
@ -139,10 +139,10 @@ jobs:
- name: Python tests
run: cmake --build build2 --target pytest
- name: C++ tests
# TODO: Figure out how to load the DLL on Python 3.8+
if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10-dev'))"
run: cmake --build build2 --target cpptest
#- name: C++ tests
# # TODO: Figure out how to load the DLL on Python 3.8+
# if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10-dev'))"
# run: cmake --build build2 --target cpptest
- name: Interface test
run: cmake --build build2 --target test_cmake_build
@ -754,7 +754,7 @@ jobs:
cmake -S . -B build
-G "Visual Studio 16 2019" -A Win32
-DPYBIND11_WERROR=ON
-DDOWNLOAD_CATCH=ON
-DDOWNLOAD_CATCH=OFF
-DDOWNLOAD_EIGEN=ON
${{ matrix.args }}
- name: Build C++11
@ -800,7 +800,7 @@ jobs:
cmake -S . -B build
-G "Visual Studio 14 2015" -A x64
-DPYBIND11_WERROR=ON
-DDOWNLOAD_CATCH=ON
-DDOWNLOAD_CATCH=OFF
-DDOWNLOAD_EIGEN=ON
- name: Build C++14
@ -849,7 +849,7 @@ jobs:
cmake -S . -B build
-G "Visual Studio 15 2017" -A x64
-DPYBIND11_WERROR=ON
-DDOWNLOAD_CATCH=ON
-DDOWNLOAD_CATCH=OFF
-DDOWNLOAD_EIGEN=ON
-DCMAKE_CXX_STANDARD=${{ matrix.std }}
${{ matrix.args }}

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@ -657,12 +657,6 @@ public:
PYBIND11_NOINLINE bool load_impl(handle src, bool convert) {
if (!src) return false;
if (!typeinfo) return try_load_foreign_module_local(src);
if (src.is_none()) {
// Defer accepting None to other overloads (if we aren't in convert mode):
if (!convert) return false;
value = nullptr;
return true;
}
auto &this_ = static_cast<ThisT &>(*this);
this_.check_holder_compat();
@ -731,7 +725,19 @@ public:
}
// Global typeinfo has precedence over foreign module_local
return try_load_foreign_module_local(src);
if (try_load_foreign_module_local(src)) {
return true;
}
// Custom converters didn't take None, now we convert None to nullptr.
if (src.is_none()) {
// Defer accepting None to other overloads (if we aren't in convert mode):
if (!convert) return false;
value = nullptr;
return true;
}
return false;
}

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@ -118,6 +118,14 @@ int none3(std::shared_ptr<NoneTester> &obj) { return obj ? obj->answer : -1; }
int none4(std::shared_ptr<NoneTester> *obj) { return obj && *obj ? (*obj)->answer : -1; }
int none5(const std::shared_ptr<NoneTester> &obj) { return obj ? obj->answer : -1; }
// Issue #2778: implicit casting from None to object (not pointer)
class NoneCastTester {
public:
int answer = -1;
NoneCastTester() = default;
NoneCastTester(int v) : answer(v) {};
};
struct StrIssue {
int val = -1;
@ -354,6 +362,16 @@ TEST_SUBMODULE(methods_and_attributes, m) {
m.def("no_none_kwarg", &none2, "a"_a.none(false));
m.def("no_none_kwarg_kw_only", &none2, py::kw_only(), "a"_a.none(false));
// test_casts_none
// Issue #2778: implicit casting from None to object (not pointer)
py::class_<NoneCastTester>(m, "NoneCastTester")
.def(py::init<>())
.def(py::init<int>())
.def(py::init([](py::none const&) { return NoneCastTester{}; }));
py::implicitly_convertible<py::none, NoneCastTester>();
m.def("ok_obj_or_none", [](NoneCastTester const& foo) { return foo.answer; });
// test_str_issue
// Issue #283: __str__ called on uninitialized instance when constructor arguments invalid
py::class_<StrIssue>(m, "StrIssue")

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@ -431,6 +431,17 @@ def test_accepts_none(msg):
assert "incompatible function arguments" in str(excinfo.value)
def test_casts_none(msg):
"""#2778: implicit casting from None to object (not pointer)"""
a = m.NoneCastTester()
assert m.ok_obj_or_none(a) == -1
a = m.NoneCastTester(4)
assert m.ok_obj_or_none(a) == 4
a = m.NoneCastTester(None)
assert m.ok_obj_or_none(a) == -1
assert m.ok_obj_or_none(None) == -1
def test_str_issue(msg):
"""#283: __str__ called on uninitialized instance when constructor arguments invalid"""