info stops schema descent on "traversable" node

[braingram]

Description of the problem

_node_info collection stops descending into a schema if the node is "traversable" (has __asdf_traverse__).

asdf/asdf/_node_info.py

Lines 276 to 277 in a866c98

	if parent.schema is not None and not cls.traversable(node):
	info.set_schema_for_property(parent, identifier)

even if the parent has a non-None schema. This seems incorrect as a node with __asdf_traverse__ may have a valid subschema.

Example of the problem

import asdf

MY_TAG_URI = "asdf://somewhere.org/tags/foo-1.0.0"
MY_SCHEMA_URI = "asdf://somewhere.org/tags/foo-1.0.0"

schema_bytes = f"""%YAML 1.1
---
$schema: "http://stsci.edu/schemas/yaml-schema/draft-01"
id: {MY_SCHEMA_URI}
title: "some title"
properties:
    foo:
        type: object
        properties:
            bar:
                title: "bar title"
""".encode("ascii")


class MyExtension:
    extension_uri = "asdf://somewhere.org/extensions/foo-1.0.0"
    tags = [asdf.extension.TagDefinition(
        MY_TAG_URI,
        schema_uris=[MY_SCHEMA_URI],
    )]


asdf.get_config().add_resource_mapping({MY_SCHEMA_URI: schema_bytes})


class FooThing:
    def __asdf_traverse__(self):
        return {"bar": 1}

class Thing:
    _tag = MY_TAG_URI

    def __asdf_traverse__(self):
        return {"foo": FooThing()}


ext = MyExtension()

with asdf.config_context() as cfg:
    cfg.add_extension(ext)
    af = asdf.AsdfFile({"t": Thing()})
    af.info()
    print(af.schema_info("title"))

Outputs:

└─t (Thing) # some title
  └─foo (FooThing)
    └─bar (int): 1
{'t': {'title': some title}}

Note that bar has a valid and singular subschema with a title resolvable by _node_info which is not used because FooThing implements __asdf_traverse__. If instead Thing.__asdf_traverse__ returned {"foo": {"bar": 1}} the output includes the title:

root (AsdfObject)
└─t (Thing) # some title
  └─foo (dict)
    └─bar (int): 1 # bar title
{'t': {'foo': {'bar': {'title': bar title}}, 'title': some title}}

System information

asdf version: main
python version: 3.12
operating system: mac