[Bug] from_h5ad => tiledbsoma._exception.SOMAError ... database already exists

[nick-youngblut]

Describe the bug

The tiledbsoma.io.from_h5ad docs state:

ingest_mode –

The ingestion type to perform:

write: Writes all data, creating new layers if the SOMA already exists.

However, running tiledbsoma.io.from_h5ad with an existing database just results in:

tiledbsoma._exception.SOMAError: /path/to/database/ already exists

Maybe registration_mapping is required, as somewhat described in the append tutorial, but the append tutorial does not show an example of using tiledbsoma.io.from_h5ad, and the registration mapping docs at tiledbsoma.io.from_h5ad are not clear.

To Reproduce

for h5ad_file in h5ad_files:
    tiledbsoma.io.from_h5ad(
            db_uri, 
            h5ad_file, 
            measurement_name="RNA", 
            ingest_mode="write", 
    )

Versions (please complete the following information):

• TileDB-SOMA version: 1.15.4
• Language and language version (e.g. Python 3.9, R 4.3.2): Python 3.12.8
• OS (e.g. MacOS, Ubuntu Linux): Linux

Additional context

More generally, it would help to clarify the usefulness of tiledbsoma.io.from_h5ad versus just using scanpy.read_h5ad with tiledbsoma.io.from_anndata, given that tiledbsoma.io.from_h5ad loads all of the data into memory.