AsdfInFits deprecation and move to stdatamodels

[braingram]

• Also revert Catch more deprecations from ASDF develop #1021 if applicable
• Also revert Catch deprecation warning for ASDF entry point #1024 if applicable

Blocked by:

• JP-3110 Move dqflags and related from stcal to stdatamodels spacetelescope/stdatamodels#134

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The ability to read AsdfInFits files is being moved from ASDF into stdatamodels (in part to consolidate non-pipeline code for jwst). The current plan for this move is:

• include AsdfInFits in stdatamodels: Reimplement support for ASDF-in-FITS in this package spacetelescope/stdatamodels#110
• release a stable version of stdatamodels EDIT: see comment below on stdatamodels >1.0
• drop AsdfInFits support in ASDF 3.0: Drop support for ASDF-in-FITS asdf-format/asdf#1288

We do not have a estimate for when a stable version of stdatamodels or ASDF 3.0 will be released. We are planning to release ASDF 2.15 (which will support AsdfInFits) in the next few weeks which we will continue to support for at least 1 year (please see our proposed release and support process).

To summarize, at some point in the next year or so the uses of AsdfInFits in specutils and opening of fits files using asdf.open will need to be updated.

I've found a usage of AsdfInFits in a test fixture

specutils/specutils/io/default_loaders/tests/test_jwst_reader.py

Lines 407 to 411 in fc04cd6

	# Mock the ASDF extension
	hdulist.append(fits.BinTableHDU(name='ASDF'))
	ff = fits_embed.AsdfInFits(hdulist, tmp_asdf)
	tmpfile = str(tmpdir.join('jwst_embedded_asdf.fits'))
	ff.write_to(tmpfile)

and likely usage in jwst_reader.py

specutils/specutils/io/default_loaders/jwst_reader.py

Lines 557 to 559 in fc04cd6

	# Get a list of GWCS objects from the slits
	with asdf.open(filename) as af:
	wcslist = [af.tree["meta"]["wcs"]]

I am happy to discuss alternatives, suggestions, comments on this process and hope to make it as painless as possible.

Also see:

• ASDF legacy converter system is being deprecated #1011

🐱

[pllim]

Will the work to address this also naturally address #1011 ?

[braingram]

The two issues are mostly unrelated (aside from both relying on deprecated or soon to be deprecated ASDF features).

To provide a minor update to this issue, a version of stdatamodels with AsdfInFits support has been released:
https://pypi.org/project/stdatamodels/1.1.0/
with documentation on reading and writing AsdfInFits files: https://stdatamodels.readthedocs.io/en/latest/asdf_in_fits.html