JSAPI returns undefined for a null value in table data

[vbabich]

Description

The value retrieved from a table via the JSAPI doesn't match the value shown in the console.

Steps to reproduce

• On a DHE VM, run this snippet in a Core+ groovy console:

ts = emptyTable(1).update("X=(String)null")
println ts.getColumnSource("X").get(0)
// Prints "null"

• Create a Core+ Groovy PQ with the snippet above, save it as TestPQ
• Open https://<vm>/irisapi/table_viewport.html
• Run this snippet in the browser console:

var { default: getObject } = await import('./get_object.js')
async function getValue(queryName, tableName, colName, rowIndex) {
    var q = c.getKnownConfigs().find(q => q.name === queryName)
    var t = await getObject(c, q, tableName)
    console.log('size:', t.size)
    t.setViewport(rowIndex, rowIndex)
    var v = await t.getViewportData()
    var column = t.findColumn(colName)
    console.log('viewport, column:', v, column)
    return v.rows[0].get(column);
}
var value = await getValue('TestPQ', 'ts', 'X', 0)
console.log('value, type:', value, typeof value)
// Prints "value, type: undefined undefined"

Expected results

Value retrieved via JSAPI matches the value returned by ts.getColumnSource("X").get(0) in the Code Studio

Actual results

JSAPI returns undefined when the actual value in the table is null

Versions

• Core+: 0.33.3

[niloc132]

We may categorize this as a "known issue, not planned", this happens in a few places, and always has done so. EDIT: this may not be true, I'll investigate further.

Will investigate briefly as part of #188.

[mofojed]

To test in JSAPI page (e.g. from http://localhost:10000/jsapi/table_basic.html), enter this in the browser console:

var dh = (await import('./dh-core.js')).default
var client = new dh.CoreClient(window.location.protocol + "//" + window.location.host);
await client.login({type: 'io.deephaven.authentication.psk.PskAuthenticationHandler', token: 'iris'});
var connection = await client.getAsIdeConnection();
var ide = await connection.startSession("python");
await ide.runCode(`
from deephaven import empty_table

x = empty_table(1).update("X=(String)null")
`)


var x = await connection.getObject({ type: 'Table', name: 'x' })
x.setViewport(0, 0)
var data = await x.getViewportData()
var value = data.get(0).get(x.columns[0])
console.log('Value is', value, ', isNull?=', value === null)

We should expect the value to be null, not undefined.

[niloc132]

PR up is, tested in plain DHC:

• edit table_viewport.html to instead run this simple script:

from deephaven import time_table, empty_table
remoteTable = empty_table(1).update("X=(String)null")

• added a breakpoint in table_viewport.html on line 144, inside the loop:
  

  deephaven-core/web/client-api/src/main/java/io/deephaven/web/public/table_viewport.html

  Line 114 in 77cb7ea

  td.textContent = rows[i].get(table.columns[j]);

• eval'd rows[i].get(table.columns[j]) in the browser console

When this bug is happening, the result should be undefined - after the fix, the expected result instead is null.