type_caster_generic::cast(): The values of
wrapper->value
wrapper->owned
are incorrect in the case that a return value policy of 'copy' is
requested but there is no copy-constructor. (Similarly 'move'.) In
particular, if the source object is a static instance, the destructor of
the 'object' 'inst' leads to class_::dealloc() which incorrectly
attempts to 'delete' the static instance.
This commit re-arranges the code to be clearer as to what the values of
'value' and 'owned' should be in the various cases. Behaviour is
different to previous code only in two situations:
policy = copy but no copy-ctor: Old code leaves 'value = src, owned =
true', which leads to trouble. New code leaves 'value = nullptr, owned
= false', which is correct.
policy = move but no move- or copy-ctor: old code leaves 'value = src,
owned = true', which leads to trouble. New code leaves 'value =
nullptr, owned = false', which is correct.
With this there is no more need for manual user declarations like
`PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>)`. Existing ones
will still compile without error -- they will just be ignored silently.
Resolves#446.
This prevents unwanted conversions to bool or int such as:
```
py::object my_object;
std::cout << my_object << std::endl; // compiles and prints 0 or 1
int n = my_object; // compiles and is nonsense
```
With `explicit operator bool()` the above cases become compiler errors.
We have various classes that have non-explicit constructors that accept
a single argument, which is implicitly making them implicitly
convertible from the argument. In a few cases, this is desirable (e.g.
implicit conversion of std::string to py::str, or conversion of double
to py::float_); in many others, however, it is unintended (e.g. implicit
conversion of size_t to some pre-declared py::array_t<T> type).
This disables most of the unwanted implicit conversions by marking them
`explicit`, and comments the ones that are deliberately left implicit.
This convenience function ensures that a py::object is either a
py::array, or the implementation will try to convert it into one. Layout
requirements (such as c_style or f_style) can be also be provided.
This patch adds an extra base handle parameter to most ``py::array`` and
``py::array_t<>`` constructors. If specified along with a pointer to
data, the base object will be registered within NumPy, which increases
the base's reference count. This feature is useful to create shallow
copies of C++ or Python arrays while ensuring that the owners of the
underlying can't be garbage collected while referenced by NumPy.
The commit also adds a simple test function involving a ``wrap()``
function that creates shallow copies of various N-D arrays.
