BUG: npy_PyFile_Dup2 - fix PyFile_AsFile failing on io style classes

This bug only manifests itself in the Python 2 code path.

Falls back to the current Python 3 code path also on Python 2 because
the Python 3 code path is written precisely to handle this situation.

Also fix tests, and clarify in the documentation that the current
implementation requires the stream to be seekable.

1 files changed, 21 insertions, 27 deletions

diff --git a/numpy/core/include/numpy/npy_3kcompat.h b/numpy/core/include/numpy/npy_3kcompat.h
index cdab1bbe8..c0aa1eb2e 100644
--- a/numpy/core/include/numpy/npy_3kcompat.h
+++ b/numpy/core/include/numpy/npy_3kcompat.h
@@ -148,7 +148,7 @@ PyUnicode_Concat2(PyObject **left, PyObject *right)
 /*
  * PyFile_* compatibility
  */
-#if defined(NPY_PY3K)
+
 /*
  * Get a FILE* handle to the file represented by the Python object
  */
@@ -160,6 +160,13 @@ npy_PyFile_Dup2(PyObject *file, char *mode, npy_off_t *orig_pos)
     npy_off_t pos;
     FILE *handle;
 
+    /* For Python 2 PyFileObject, use PyFile_AsFile */
+#if !defined(NPY_PY3K)
+    if (PyFile_Check(file)) {
+        return PyFile_AsFile(file);
+    }
+#endif
+
     /* Flush first to ensure things end up in the file in the correct order */
     ret = PyObject_CallMethod(file, "flush", "");
     if (ret == NULL) {
@@ -257,6 +264,13 @@ npy_PyFile_DupClose2(PyObject *file, FILE* handle, npy_off_t orig_pos)
     PyObject *ret, *io, *io_raw;
     npy_off_t position;
 
+    /* For Python 2 PyFileObject, do nothing */
+#if !defined(NPY_PY3K)
+    if (PyFile_Check(file)) {
+        return 0;
+    }
+#endif
+
     position = npy_ftell(handle);
 
     /* Close the FILE* handle */
@@ -314,6 +328,12 @@ static NPY_INLINE int
 npy_PyFile_Check(PyObject *file)
 {
     int fd;
+    /* For Python 2, check if it is a PyFileObject */
+#if !defined(NPY_PY3K)
+    if (PyFile_Check(file)) {
+        return 1;
+    }
+#endif
     fd = PyObject_AsFileDescriptor(file);
     if (fd == -1) {
         PyErr_Clear();
@@ -322,32 +342,6 @@ npy_PyFile_Check(PyObject *file)
     return 1;
 }
 
-#else
-
-static NPY_INLINE FILE *
-npy_PyFile_Dup2(PyObject *file,
-                const char *NPY_UNUSED(mode), npy_off_t *NPY_UNUSED(orig_pos))
-{
-    FILE * fp = PyFile_AsFile(file);
-    if (fp == NULL) {
-        PyErr_SetString(PyExc_IOError,
-                        "first argument must be an open file");
-        return NULL;
-    }
-    return fp;
-}
-
-static NPY_INLINE int
-npy_PyFile_DupClose2(PyObject *NPY_UNUSED(file), FILE* NPY_UNUSED(handle),
-                     npy_off_t NPY_UNUSED(orig_pos))
-{
-    return 0;
-}
-
-#define npy_PyFile_Check PyFile_Check
-
-#endif
-
 static NPY_INLINE PyObject*
 npy_PyFile_OpenFile(PyObject *filename, const char *mode)
 {