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https://issues.apache.org/jira/browse/NIFI-14664?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17984977#comment-17984977
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Daniel Stieglitz edited comment on NIFI-14664 at 6/20/25 4:27 PM:
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[~zhongwei.long] You are welcome. Glad to help!
I believe although I cannot conclusively say that it is a special case in Jolt
specification parsing. I have been running the code in a debugger and the
problems start at line 185 in JoltTransformJSON.
{code:java}
final Object transformedJson = TransformUtils.transform(transform,
inputJson);{code}
When stepping into this code until where the actual Jolt API is called
(com.bazaarvoice.jolt.Chainr in the for loop on lines 95-97) I see where
"suggestedMax" is shifted but for some reason on subsequent calls
"suggestedMax" has been copied already to the c.options.scales.xAxes[0].ticks
section even before the last rule hence the result of getting multiple values
for "suggestedMax". It would seem that the "modify-define-beta" somehow is
filling that section already. I am still unsure why it does this.
You certainly made the right move simplifying your transformations. If you want
to look at this further run the following Google query
{code:java}
Jolt modify-define-beta copying more than expected"{code}
and see the suggestions given there as it gives possible reasons for this
operation copying more than expected.
was (Author: JIRAUSER294662):
[~zhongwei.long] You are welcome. Glad to help!
I believe although I cannot conclusively say that it is a special case in Jolt
specification parsing. I have been running the code in a debugger and the
problems start at line 185 in JoltTransformJSON.
{code:java}
final Object transformedJson = TransformUtils.transform(transform,
inputJson);{code}
When stepping into this code until where the actual Jolt API is called
(com.bazaarvoice.jolt.Chainr in the for loop on lines 95-97) I see where
"suggestedMax" is shifted but for some reason on subsequent calls
"suggestedMax" has been copied already to the c.options.scales.xAxes[0].ticks
section even before the last rule hence the result of getting multiple values
for "suggestedMax". It would seem that the "modify-define-beta" somehow is
filling that section already. I am still unsure why it does this.
You certainly made the right move simplifying your transformations. If you want
to look at this further run the following Google query
{code:java}
Jolt modify-define-beta copying more than expected" and see the suggestions
given{code}
there it gives possible reasons for this operation copying more than expected.
> JoltTransformJSON repeatedly appends values to fields on re-execution
> ---------------------------------------------------------------------
>
> Key: NIFI-14664
> URL: https://issues.apache.org/jira/browse/NIFI-14664
> Project: Apache NiFi
> Issue Type: Bug
> Components: Examples
> Affects Versions: 2.4.0
> Reporter: le.zw
> Priority: Major
> Labels: jolt
> Attachments: JOLT_Test.json, image-2025-06-16-16-15-40-471.png,
> image-2025-06-16-16-25-51-932.png, image-2025-06-16-16-29-05-004.png
>
>
> input JSON
> {code:java}
> [
> {
> "category": "05-01",
> "value": 218
> },
> {
> "category": "05-02",
> "value": 219
> },
> {
> "category": "05-03",
> "value": 170
> }
> ]
> {code}
> JOLT spec：
> {code:java}
> [
> {
> "operation": "shift",
> "spec": {
> "*": {
> "category": "c.data.labels.[&1]",
> "value": "c.data.datasets[0].data"
> }
> }
> },
> {
> "operation": "modify-overwrite-beta",
> "spec": {
> "max": "=max(@(1,c.data.datasets[0].data))"
> }
> },
> {
> "operation": "modify-overwrite-beta",
> "spec": {
> "suggestedMax": "=intSum(@(1,max),20)"
> }
> },
> {
> "operation": "modify-define-beta",
> "spec": {
> "c": {
> "type": "horizontalBar",
> "data": {
> "datasets": {
> "*": {
> "label": "Orders",
> "backgroundColor": "gold"
> }
> }
> },
> "options": {
> "scales": {
> "xAxes": [
> {
> "gridLines": {
> "display": true,
> "drawOnChartArea": false,
> "tickMarkLength": 8,
> "zeroLineWidth": 1,
> "zeroLineColor": "black",
> "color": "black"
> },
> "ticks": {
> "fontColor": "black",
> "beginAtZero": true
> }
> }
> ],
> "yAxes": [
> {
> "display": true,
> "position": "left",
> "gridLines": {
> "display": true,
> "drawOnChartArea": false,
> "tickMarkLength": 8,
> "color": "black"
> },
> "ticks": {
> "fontColor": "black",
> "fontSize": "8"
> }
> }
> ]
> },
> "legend": {
> "display": false
> },
> "plugins": {
> "datalabels": {
> "anchor": "end",
> "align": "end",
> "color": "black",
> "font": {
> "size": 10,
> "weight": "bold"
> }
> }
> }
> }
> }
> }
> },
> {
> "operation": "shift",
> "spec": {
> "c": {
> "options": {
> "scales": {
> "xAxes": {
> "*": "c.options.scales.xAxes[#2].&"
> },
> "yAxes": {
> "*": "c.options.scales.yAxes[#3].&"
> }
> },
> "*": {
> "@": "c.options.&0"
> }
> },
> "*": {
> "@": "c.&0"
> }
> },
> "suggestedMax": "c.options.scales.xAxes[0].ticks.suggestedMax"
> }
> }
> ]
> {code}
> On repeated executions, the suggestedMax field is transformed into an array
> whose number of elements increases over time.
> *After the first execution, {{suggestedMax}} is a single value:*
> *!image-2025-06-16-16-25-51-932.png!*
> *After the second execution, the {{suggestedMax}} field is transformed into
> an array containing two values:*
> *!image-2025-06-16-16-29-05-004.png!*
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