Matching Python 2 int behavior on Python 2 (#1186)
Pybind11's default conversion to int always produces a long on Python 2 (`int`s and `long`s were unified in Python 3). This patch fixes `int` handling to match Python 2 on Python 2; for short types (`size_t` or smaller), the number will be returned as an `int` if possible, otherwise `long`. Requires Python 2.5+.
This is needed for things like `sys.exit`, which refuse to accept a `long`.
diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index 715ec93..b3ab7f2 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -980,11 +980,12 @@
static handle cast(T src, return_value_policy /* policy */, handle /* parent */) {
if (std::is_floating_point<T>::value) {
return PyFloat_FromDouble((double) src);
- } else if (sizeof(T) <= sizeof(long)) {
+ } else if (sizeof(T) <= sizeof(ssize_t)) {
+ // This returns a long automatically if needed
if (std::is_signed<T>::value)
- return PyLong_FromLong((long) src);
+ return PYBIND11_LONG_FROM_SIGNED(src);
else
- return PyLong_FromUnsignedLong((unsigned long) src);
+ return PYBIND11_LONG_FROM_UNSIGNED(src);
} else {
if (std::is_signed<T>::value)
return PyLong_FromLongLong((long long) src);
diff --git a/include/pybind11/detail/common.h b/include/pybind11/detail/common.h
index 7692063..7d629c0 100644
--- a/include/pybind11/detail/common.h
+++ b/include/pybind11/detail/common.h
@@ -158,6 +158,8 @@
#define PYBIND11_BYTES_SIZE PyBytes_Size
#define PYBIND11_LONG_CHECK(o) PyLong_Check(o)
#define PYBIND11_LONG_AS_LONGLONG(o) PyLong_AsLongLong(o)
+#define PYBIND11_LONG_FROM_SIGNED(o) PyLong_FromSsize_t((ssize_t) o)
+#define PYBIND11_LONG_FROM_UNSIGNED(o) PyLong_FromSize_t((size_t) o)
#define PYBIND11_BYTES_NAME "bytes"
#define PYBIND11_STRING_NAME "str"
#define PYBIND11_SLICE_OBJECT PyObject
@@ -180,6 +182,8 @@
#define PYBIND11_BYTES_SIZE PyString_Size
#define PYBIND11_LONG_CHECK(o) (PyInt_Check(o) || PyLong_Check(o))
#define PYBIND11_LONG_AS_LONGLONG(o) (PyInt_Check(o) ? (long long) PyLong_AsLong(o) : PyLong_AsLongLong(o))
+#define PYBIND11_LONG_FROM_SIGNED(o) PyInt_FromSsize_t((ssize_t) o) // Returns long if needed.
+#define PYBIND11_LONG_FROM_UNSIGNED(o) PyInt_FromSize_t((size_t) o) // Returns long if needed.
#define PYBIND11_BYTES_NAME "str"
#define PYBIND11_STRING_NAME "unicode"
#define PYBIND11_SLICE_OBJECT PySliceObject
diff --git a/tests/test_builtin_casters.cpp b/tests/test_builtin_casters.cpp
index e5413c2..4508134 100644
--- a/tests/test_builtin_casters.cpp
+++ b/tests/test_builtin_casters.cpp
@@ -155,4 +155,9 @@
// test_complex
m.def("complex_cast", [](float x) { return "{}"_s.format(x); });
m.def("complex_cast", [](std::complex<float> x) { return "({}, {})"_s.format(x.real(), x.imag()); });
+
+ // test int vs. long (Python 2)
+ m.def("int_cast", []() {return (int) 42;});
+ m.def("long_cast", []() {return (long) 42;});
+ m.def("longlong_cast", []() {return ULLONG_MAX;});
}
diff --git a/tests/test_builtin_casters.py b/tests/test_builtin_casters.py
index 2f311f1..01d0437 100644
--- a/tests/test_builtin_casters.py
+++ b/tests/test_builtin_casters.py
@@ -323,3 +323,16 @@
assert convert(np.bool_(False)) is False
assert noconvert(np.bool_(True)) is True
assert noconvert(np.bool_(False)) is False
+
+
+def test_int_long():
+ """In Python 2, a C++ int should return a Python int rather than long
+ if possible: longs are not always accepted where ints are used (such
+ as the argument to sys.exit()). A C++ long long is always a Python
+ long."""
+
+ import sys
+ must_be_long = type(getattr(sys, 'maxint', 1) + 1)
+ assert isinstance(m.int_cast(), int)
+ assert isinstance(m.long_cast(), int)
+ assert isinstance(m.longlong_cast(), must_be_long)