numpy.h: fixed a leak, added some comments to buffer_info

include/pybind11/common.h

@@ -143,12 +143,13 @@ PYBIND11_DECL_FMT(float,   "f"); PYBIND11_DECL_FMT(double,   "d"); PYBIND11_DECL
 
 /// Information record describing a Python buffer object
 struct buffer_info {
-    void *ptr;
-    size_t itemsize, size;
-    std::string format; // for dense contents, this should be set to format_descriptor<T>::value
-    int ndim;
-    std::vector<size_t> shape;
-    std::vector<size_t> strides;
+    void *ptr;                   // Pointer to the underlying storage
+    size_t itemsize;             // Size of individual items in bytes
+    size_t size;                 // Total number of entries
+    std::string format;          // For homogeneous buffers, this should be set to format_descriptor<T>::value
+    int ndim;                    // Number of dimensions
+    std::vector<size_t> shape;   // Shape of the tensor (1 entry per dimension)
+    std::vector<size_t> strides; // Number of entries between adjacent entries (for each per dimension)
 
     buffer_info(void *ptr, size_t itemsize, const std::string &format, int ndim,
                 const std::vector<size_t> &shape, const std::vector<size_t> &strides)

include/pybind11/numpy.h

@@ -128,9 +128,11 @@ public:
             return nullptr;
         API &api = lookup_api();
         PyObject *descr = api.PyArray_DescrFromType_(npy_format_descriptor<T>::value);
-        return api.PyArray_FromAny_(ptr, descr, 0, 0,
-                                    API::NPY_C_CONTIGUOUS_ | API::NPY_ENSURE_ARRAY_ |
-                                    API::NPY_ARRAY_FORCECAST_, nullptr);
+        PyObject *result = api.PyArray_FromAny_(
+            ptr, descr, 0, 0, API::NPY_C_CONTIGUOUS_ | API::NPY_ENSURE_ARRAY_
+                            | API::NPY_ARRAY_FORCECAST_, nullptr);
+        Py_DECREF(ptr);
+        return result;
     }
 };