[jira] [Created] (ARROW-6921) Regression: Cannot round-trip IPC files between PyArrow and Arrow JS

["Joe Quigley (Jira)" <ji...@apache.org>]

Joe Quigley created ARROW-6921:
----------------------------------

             Summary:  Regression: Cannot round-trip IPC files between PyArrow and Arrow JS
                 Key: ARROW-6921
                 URL: https://issues.apache.org/jira/browse/ARROW-6921
             Project: Apache Arrow
          Issue Type: Bug
          Components: JavaScript, Python
    Affects Versions: 0.15.0, 0.15.1
         Environment: Broken PyArrow: conda-forge build 0.15.0-py37h8b68381_0
Working PyArrow: conda-forge build 0.14.1-py37h8b68381_2
Arrow JS versions tested: 0.13.0, 0.14.0 (apache-arrow@latest)
OS: Tested on Win7, Amazon Linux AMI 2018.03
Python platforms: Win7/Conda/Python 3.6, RHEL/Conda/Python 3.6
JS platforms: Node 10.15.0, Chrome 77.0.3865.120
            Reporter: Joe Quigley


Originally raised by [Sarath|https://stackoverflow.com/users/403133/sarath] on [StackOverflow|https://stackoverflow.com/questions/58313254], reporting here as I've run into this issue as well.

When exporting an Arrow table using PyArrow, ArrowJS incorrectly imports it as a 0-row table, skipping any data in the table. The schema is imported correctly, including metadata, but the length of the table is 0.

{code:python}
import pyarrow as pa
table = pa.Table.from_pydict( {"a": [1, 2, 3], "b": [4, 5, 6]} )

with pa.RecordBatchFileWriter('file.arrow', table.schema) as writer:
    writer.write_table(table)
{code}

If {{file.arrow}} was generated with PyArrow 0.15, the following JS snippet will fail. However, if you generated it with PyArrow 0.14, then the JS snippet will work as expected:

{code:javascript}
const { readFileSync } = require("fs");
const { Table } = require("apache-arrow");

const data = readFileSync("file.arrow");
const table = Table.from([ data ]);

console.assert(table.length === 3, "Table should have 3 rows");
console.assert(table.get(0) != null, "First row should not be null");
{code}

Tested with PyArrow 0.14.1, 0.15.0, and ArrowJS 0.13.0 and 0.14.1.



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