schema_info path argument does not appear to support items in lists

[braingram]

Description of the problem

If a node is nested within a list I'm unable to find a schema_info path argument that will return the expected result.

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({
        "my_list": [
            0,  # not a Thing
            Thing(),
        ]
    })
    print(af.schema_info("title", "my_list.1"))

Results in an error:

line 103, in collect_schema_info
    info = info.get(path_key, None)
AttributeError: 'list' object has no attribute 'get'

Using preserve_list=False returns None (not the expected title). Trying mylist[1] return None in both cases.

System information

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