FITS objects created with fromstring have problems?

[embray]

I have some FITS objects being created from strings. I can't access their data attribute. I think it has to do with _orig_bitpix being negative, possibly, but I'm not sure. @embray any thoughts? I can provide an example if needed.

In [32]: blah._orig_bitpix
Out[32]: -32

In [33]: blah.data
Traceback (most recent call last):
  File "<ipython-input-33-dd8ff7218a27>", line 1, in <module>
    blah.data
  File "/Users/adam/repos/astropy/astropy/utils/misc.py", line 286, in __get__
    val = self._fget(obj)
  File "/Users/adam/repos/astropy/astropy/io/fits/hdu/image.py", line 218, in data
    data = self._get_scaled_image_data(self._data_offset, self.shape)
  File "/Users/adam/repos/astropy/astropy/io/fits/hdu/image.py", line 594, in _get_scaled_image_data
    if self._file.memmap:
AttributeError: 'NoneType' object has no attribute 'memmap'

> /Users/adam/repos/astropy/astropy/io/fits/hdu/image.py(594)_get_scaled_image_data()
    593             else:  # floating point cases
--> 594                 if self._file.memmap:
    595                     data = raw_data.copy()

[embray]

That's likely--it looks like it's going down a code path there which doesn't properly support the case of FITS files read from memory buffers (as is the case for fromstring). Should be an easy fix.

[embray]

Attached a PR that should fix this.

[keflavich]

Should that be 'if needed' ?

[embray]

Yeah, but I'm not going to push another commit just to fix a one letter typo in a comment :) It'll be fixed elsewhen.