info and schema_info fails to display title (or other schema attributes) for items that don't implement __asdf_traverse__

[braingram]

Description of the problem

info (and schema_info) silently fails to display schema title for custom item's that don't implement __asdf_traverse__

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"
""".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 Thing:
    _tag = MY_TAG_URI

    def __asdf_traverse__(self):
        return []


ext = MyExtension()

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

Outputs:

root (AsdfObject)
└─t (Thing): <__main__.Thing object at 0x1029194b0> # some title

Rerunning the example after removing Thing.__asdf_traverse__ outputs:

root (AsdfObject)
└─t (Thing): <__main__.Thing object at 0x103ee13f0>

Note the missing title.

System information

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