BUG: Fix segfault when an error occurs in np.fromfile

There is a problem with the way in which we handle
errors which occur in the call to `PyArray_FromFile`
in `np.fromfile`.

The problem here is twofold.

 1. The return value isn't checked, therefore if we reach
    the fail block, we will attempt a DECREF on a NULL and
    go down in flames.

 2. The cleanup code on the filepointers (most notabily the
    call to `npy_PyFile_DupClose2`) assumes that there is no
    error set to work.

This PR addresses these issues
 1. By adding a NULL check to the fail block to ensure we don't
    attempt a DECREF on a NULL.

 2. By saving the error state before attempting the cleanup code
    on the file descriptor, and then restoring it after.

Fixes: #12300

0 files changed, 0 insertions, 0 deletions