fix: Correct FilledAreaPlot x-value validation across groups

[VuMartin]

What changes were proposed in this PR?

Fixed the FilledAreaPlot validation logic for grouped data with shared X-values.

- X_values = x_values.union(set(group[$x].unique()))
+ x_values = x_values.union(set(group[$x].unique()))

Previously, the validation incorrectly handled X-value comparisons between groups, causing valid charts to be rejected. The logic was updated so that X-values are tracked across groups correctly when checking whether groups share compatible X attributes.

Before:

After:

Any related issues, documentation, discussions?

Fixes #6728

How was this PR tested?

Tested by running Texera locally and executing a FilledAreaPlot workflow with grouped data.
CSV File:
filled_area_test.csv

Verified:

• Valid grouped charts are accepted and rendered.
• Invalid inputs missing X/Y attributes still return the appropriate error message.
• Python UDF execution works after generating Python proto bindings and installing required Python dependencies.

Was this PR authored or co-authored using generative AI tooling?

Generated-by: ChatGPT (GPT-5.5-mini)

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @eugenegujing
  You can notify them by mentioning @eugenegujing in a comment.

[github-actions]

⚠️ Benchmark changes need a look

🟢 2 better · 🔴 5 worse · ⚪ 8 noise (<±5%) · 0 without baseline

Compared against main 7e4a9b4 benchmarked on this same runner, so the delta is largely free of cross-runner hardware noise. The "7d avg" column still reflects the gh-pages dashboard. Treat <±5% as noise unless repeated.

Dashboard · Run

	config	throughput	MB/s	latency	max Δ latest / 7d
🔴	bs=10 sw=10 sl=64	393	0.24	25,644/30,735/30,735 us	🔴 +19.7% / 🔴 +100.1%
🔴	bs=100 sw=10 sl=64	789	0.482	125,189/159,743/159,743 us	🔴 +6.6% / 🔴 +46.4%
⚪	bs=1000 sw=10 sl=64	902	0.551	1,112,988/1,152,143/1,152,143 us	⚪ within ±5% / 🔴 +11.0%

Baseline details

Latest main 7e4a9b4 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	393 tuples/sec	437 tuples/sec	754.55 tuples/sec	-10.1%	-47.9%
bs=10 sw=10 sl=64	MB/s	0.24 MB/s	0.267 MB/s	0.461 MB/s	-10.1%	-47.9%
bs=10 sw=10 sl=64	p50	25,644 us	21,428 us	12,816 us	+19.7%	+100.1%
bs=10 sw=10 sl=64	p95	30,735 us	34,536 us	16,594 us	-11.0%	+85.2%
bs=10 sw=10 sl=64	p99	30,735 us	34,536 us	19,806 us	-11.0%	+55.2%
bs=100 sw=10 sl=64	throughput	789 tuples/sec	806 tuples/sec	969.38 tuples/sec	-2.1%	-18.6%
bs=100 sw=10 sl=64	MB/s	0.482 MB/s	0.492 MB/s	0.592 MB/s	-2.0%	-18.5%
bs=100 sw=10 sl=64	p50	125,189 us	121,121 us	103,584 us	+3.4%	+20.9%
bs=100 sw=10 sl=64	p95	159,743 us	149,888 us	109,097 us	+6.6%	+46.4%
bs=100 sw=10 sl=64	p99	159,743 us	149,888 us	117,304 us	+6.6%	+36.2%
bs=1000 sw=10 sl=64	throughput	902 tuples/sec	908 tuples/sec	1,004 tuples/sec	-0.7%	-10.1%
bs=1000 sw=10 sl=64	MB/s	0.551 MB/s	0.554 MB/s	0.613 MB/s	-0.5%	-10.1%
bs=1000 sw=10 sl=64	p50	1,112,988 us	1,107,485 us	1,002,357 us	+0.5%	+11.0%
bs=1000 sw=10 sl=64	p95	1,152,143 us	1,146,636 us	1,046,463 us	+0.5%	+10.1%
bs=1000 sw=10 sl=64	p99	1,152,143 us	1,146,636 us	1,073,661 us	+0.5%	+7.3%

Raw CSV

config_idx,batch_size,schema_width,string_len,num_batches,total_ms,total_tuples,total_bytes,tuples_per_sec,mb_per_sec,lat_p50_us,lat_p95_us,lat_p99_us
0,10,10,64,20,509.34,200,128000,393,0.240,25643.96,30734.66,30734.66
1,100,10,64,20,2533.79,2000,1280000,789,0.482,125188.64,159742.68,159742.68
2,1000,10,64,20,22160.85,20000,12800000,902,0.551,1112988.13,1152142.76,1152142.76

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.96%. Comparing base (7e4a9b4) to head (f9f7816).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6894      +/-   ##
============================================
- Coverage     77.97%   76.96%   -1.02%     
- Complexity     3661     3706      +45     
============================================
  Files          1161     1174      +13     
  Lines         46059    47004     +945     
  Branches       5105     5214     +109     
============================================
+ Hits          35915    36176     +261     
- Misses         8521     9187     +666     
- Partials       1623     1641      +18     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.66% <ø> (+0.66%)	⬆️
agent-service	76.76% <ø> (ø)		Carriedforward from 7e4a9b4
amber	69.15% <100.00%> (-1.53%)	⬇️
computing-unit-managing-service	16.12% <ø> (-4.37%)	⬇️
config-service	63.57% <ø> (-3.10%)	⬇️
file-service	62.37% <ø> (-4.84%)	⬇️
frontend	82.64% <ø> (ø)		Carriedforward from 7e4a9b4
notebook-migration-service	78.94% <ø> (ø)
pyamber	92.40% <ø> (ø)		Carriedforward from 7e4a9b4
workflow-compiling-service	55.00% <ø> (-0.15%)	⬇️

*This pull request uses carry forward flags. Click here to find out more.

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[Yicong-Huang]

LGTM. cc @xuang7 for backport review

[Yicong-Huang]

let's do the backport separately