[python] Unicode data generates error upon write to dataframe

[bkmartinjr]

Creating a dataframe with a string column works fine, but when you try to write to it, it generates an error. It also appears there is no unit test for this, which would be a nice addition.

See #420 for an example unit test (currently marked xfail).

Test case:

import numpy as np
import pyarrow as pa
import pandas as pd
import tiledbsoma as soma

soma_df = soma.SOMADataFrame("./test_dataframe")

df = pd.DataFrame(data={
  'soma_rowid': np.arange(2, dtype=np.int64),
  'soma_joinid': np.arange(2, dtype=np.int64),
  'unicode': ['\N{LATIN CAPITAL LETTER E}\N{COMBINING CIRCUMFLEX ACCENT}', 'a \N{GREEK CAPITAL LETTER DELTA} test'], 
  'ascii': ['aa', 'bbb',]
})
tbl = pa.Table.from_pandas(df)
print(tbl.schema)

soma_df.create(schema=tbl.schema)
print(soma_df.schema)

soma_df.write(tbl)

Output:

soma_rowid: int64
soma_joinid: int64
unicode: string
ascii: string
-- schema metadata --
pandas: '{"index_columns": [{"kind": "range", "name": null, "start": 0, "' + 718
soma_rowid: int64
soma_joinid: int64
unicode: large_string
ascii: large_string
---------------------------------------------------------------------------
UnicodeEncodeError                        Traceback (most recent call last)
File tiledb/libtiledb.pyx:4617, in tiledb.libtiledb._setitem_impl_sparse()

UnicodeEncodeError: 'ascii' codec can't encode character '\u0302' in position 1: ordinal not in range(128)

During handling of the above exception, another exception occurred:

TileDBError                               Traceback (most recent call last)
Cell In [18], line 20
     17 soma_df.create(schema=tbl.schema)
     18 print(soma_df.schema)
---> 20 soma_df.write(tbl)

File ~/projects/TileDB-SOMA/apis/python/src/tiledbsoma/soma_dataframe.py:263, in SOMADataFrame.write(self, values)
    260 if self._get_is_sparse():
    261     # sparse write
    262     with self._tiledb_open("w") as A:
--> 263         A[rowids] = attr_cols_map
    264 else:
    265     # TODO: This was a quick thing to bootstrap some early ingestion tests but needs more thought.
    266     # In particular, rowids needn't be either zero-up or contiguous.
    267     assert len(rowids) > 0

File tiledb/libtiledb.pyx:4691, in tiledb.libtiledb.SparseArrayImpl.__setitem__()

File tiledb/libtiledb.pyx:4619, in tiledb.libtiledb._setitem_impl_sparse()

TileDBError: Attr's dtype is "ascii" but attr_val contains invalid ASCII characters

[johnkerl]

See #274 -- it is correct that we do not support writes of non-ASCII data to TileDB-SOMA at present. This is pending true Unicode support in TileDB Core.

[bkmartinjr]

FYI: writes succeeded until last week, when it started generating errors - not sure how. or what was actually stored.

[johnkerl]

#359 was merged last week -- this along with #355 was one of the 'stack of three' setting up #360 (which has become #400). This was part of the conversation we had about needing to regenerate test-census data.

[johnkerl]

@maniarathi @bkmartinjr I believe this is a duplicate of #274

[bkmartinjr]

@maniarathi @bkmartinjr I believe this is a duplicate of #274

Potentially - the description in #274 is a bit unclear to me. But as long as "support Unicode in attributes, including value_filter'ing" is the intent, OK w/ me to close as dup.

[johnkerl]

@bkmartinjr I assert that these are the same. I closed #274 in favor of this one.

[johnkerl]

@maniarathi I see your assign to @bkmartinjr -- I'm happy to help here as well as I was deep in this last year. Also note that much of this is core work within TileDB; mainly here we will be merging/validating a core release.