SpecutilsExtension ASDF extension interferes with url_mapping of other ASDF extensions (astropy, jwst)

[jdavies-st]

When running the JWST pipeline on JWST data while having the current dev version of specutils installed

specutils-0.5.2.dev45+gb873f2a|           py36_3         146 KB  http://ssb.stsci.edu/conda-dev

the specutils ASDF extension is somehow interfering with the astropy ASDF extension and remapping the location of baseframe-1.0.0.yaml to a non-existent location in the specutils package.

The correct location for this schema is in the astropy package.

The tag

tag:astropy.org:astropy/coordinates/frames/baseframe-1.0.0

should get mapped to the local installation of astropy:

astropy/io/misc/asdf/data/schemas/astropy.org/astropy/coordinates/frames/baseframe-1.0.0.yaml:

but specutils is somehow interfering and mapping it to

specutils/io/asdf/schemas/astropy.org/astropy/coordinates/frames/baseframe-1.0.0.yaml

Not good.

I don't see this bug in the last released version, specutils==0.5.2. So this only seems to be a problem in dev right now.

Full traceback below.

traceback.txt

Tagging @nden.

[jdavies-st]

Here's a simple way to reproduce what is essentially the same bug if the dev version of specutils is installed.

In [3]: import asdf

In [4]: from astropy.coordinates import FK5

In [5]: frame = FK5()

In [7]: af = asdf.AsdfFile()

In [8]: af.tree = {'frame': frame}
/Users/jdavies/miniconda3/envs/jwst_dev/lib/python3.6/site-packages/asdf/schema.py:236: 
UserWarning: Unable to locate schema file for 'tag:astropy.org:astropy/coordinates/frames/fk5-1.0.0': 'file:///Users/jdavies/miniconda3/envs/jwst_dev/lib/python3.6/site-packages/specutils/io/asdf/schemas/astropy.org/astropy/coordinates/frames/fk5-1.0.0.yaml'
  warnings.warn(msg.format(tag, schema_path))

[jdavies-st]

It looks like the bug was introduced here

#443

and is probably in the url_mapping in the extension.py module.

specutils/specutils/io/asdf/extension.py

Lines 17 to 21 in b873f2a

	SPECUTILS_URL_MAPPING = [
	(ASTROPY_SCHEMA_URI_BASE,
	filepath_to_url(
	os.path.join(SCHEMA_PATH, 'astropy.org')) +
	'/{url_suffix}.yaml')]

[jdavies-st]

I will add that this bug currently breaks all ASDF tag and schema functionality for asdf, astropy and jwst if the current dev version of specutils is installed with these other packages. So this bug is critical to get fixed before the next release of specutils happens. Please label and milestone this appropriately.