Nested references within a schema do not get resolved

[WilliamJamieson]

In this schema https://github.com/WilliamJamieson/rad/blob/237060e373b454e0f37696adbc7bee20fc73a1f0/latest/reference_files/wfi_img_photom.yaml#L1-L182 used in spacetelescope/rad#712 is not properly resolved with asdf.schema.load_schema(<uri>, resolve_references=True).

A portion of the output from this command is:

                                                          'F146': {   'allOf': [   {   '$ref': 'asdf://stsci.edu/datamodels/roman/schemas/reference_files/wfi_img_photom-1.3.0#/definitions/basic_phot_table_entry'},
                                                                                   {   'properties': {   'collecting_area': {   'type': 'number',
                                                                                                                                'unit': 'm^2'},
                                                                                                         'effective_area': {   'datatype': 'float32',
                                                                                                                               'exact_datatype': True,
                                                                                                                               'ndim': 1,
                                                                                                                               'tag': 'tag:stsci.edu:asdf/core/ndarray-1.*',
                                                                                                                               'unit': 'm^2'},
                                                                                                         'photmjsr': {   'type': 'number',
                                                                                                                         'unit': '(MJy/sr) '
                                                                                                                                 '/ '
                                                                                                                                 '(DN/s)'},
                                                                                                         'pixelareasr': {   'type': 'number',
                                                                                                                            'unit': 'sr'},
                                                                                                         'uncertainty': {   'type': 'number',
                                                                                                                            'unit': '(MJy/sr) '
                                                                                                                                    '/ '
                                                                                                                                    '(DN/s)'},
                                                                                                         'wavelength': {   'datatype': 'float32',
                                                                                                                           'exact_datatype': True,
                                                                                                                           'ndim': 1,
                                                                                                                           'tag': 'tag:stsci.edu:asdf/core/ndarray-1.*',
                                                                                                                           'unit': 'microns'}},

This is true for each of the entries in the main object. This appears to be the result of walk_and_modify not resolving the references in the output here

asdf/asdf/schema.py

Line 449 in 0e7c50c

return reference.resolve_fragment(subschema, suburl_fragment)

, and since that section of the tree has been visited by walk_and_modify when that new section of the tree is inserted it never gets back to resolving the references in that block. This maybe a result of the order that walk_and_modify decides to walk the tree.

Modifying the linked line with:

return walk_and_modify(reference.resolve_fragment(subschema, suburl_fragment), resolve_refs)

Fixes the issue.

[braingram]

Thanks for opening this issue.

It looks like a duplicate of #1727

The proposed fix here results in a RecursionError when loading the ndarray schema. A different fix will have to be found.