feat(pyamber): route ranges by unique receivers

[carloea2]

What changes were proposed in this PR?

Range shuffle now divides its key range by the deduplicated receiver count used for routing. Repeated topology channels therefore cannot produce an index beyond the receiver list.

Any related issues, documentation, discussions?

Closes #8245

How was this PR tested?

python -c "import sys,pytest; sys.path[:0]=[r'C:\Users\carlo\texera\texera-worktrees\investigate-bug59\amber\src\main\python',r'C:\Users\carlo\texera\texera\amber\src\main\python']; raise SystemExit(pytest.main(['amber/src/test/python/core/architecture/sendsemantics/test_partitioners.py','-q','-p','no:cacheprovider']))"
36 passed

ruff check amber/src/main/python amber/src/test/python
All checks passed

ruff format --check amber/src/main/python amber/src/test/python
213 files already formatted

Direct reproduction after the fix:

receivers=2 keys_per_receiver=5 index_for_9=1 target=B

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

Generated-by: Codex

[github-actions]

Backport auto-label report

This fix: PR was checked against each actively-supported release branch. release/* labels drive the post-merge backport, so add or remove one to change where this fix lands.

Release branch	Analysis
⚠️ release/v1.3	Not labeled automatically — none of the files this PR modifies exist on this branch (amber/src/main/python/core/architecture/sendsemantics/range_based_shuffle_partitioner.py, amber/src/test/python/core/architecture/sendsemantics/test_partitioners.py). The fix may target code that isn't on this release, or the files were moved/renamed after the branch was cut. Please check and add release/v1.3 by hand if this fix should be backported here.
✅ release/v1.2	Already labeled — this fix is queued to backport here.

Auto-label run.

[github-actions]

Automated Reviewer Suggestions

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

• Contributors with relevant context: @Ma77Ball, @Yicong-Huang
  You can notify them by mentioning @Ma77Ball, @Yicong-Huang in a comment.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.89%. Comparing base (50321e4) to head (f28d315).
⚠️ Report is 11 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8246      +/-   ##
============================================
- Coverage     93.93%   93.89%   -0.05%     
+ Complexity     4762     4761       -1     
============================================
  Files          1191     1191              
  Lines         48308    49051     +743     
  Branches       5377     5377              
============================================
+ Hits          45380    46058     +678     
- Misses         1494     1558      +64     
- Partials       1434     1435       +1     

Flag	Coverage Δ		*Carryforward flag
access-control-service	81.00% <ø> (ø)		Carriedforward from 50321e4
agent-service	99.32% <ø> (ø)		Carriedforward from 50321e4
amber	90.02% <ø> (-0.02%)	⬇️	Carriedforward from 50321e4
computing-unit-managing-service	73.67% <ø> (ø)		Carriedforward from 50321e4
config-service	86.86% <ø> (ø)		Carriedforward from 50321e4
file-service	87.91% <ø> (ø)		Carriedforward from 50321e4
frontend	96.41% <ø> (ø)		Carriedforward from 50321e4
notebook-migration-service	79.31% <ø> (ø)		Carriedforward from 50321e4
pyamber	97.85% <100.00%> (-1.02%)	⬇️
workflow-compiling-service	77.19% <ø> (ø)		Carriedforward from 50321e4

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

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions]

⚠️ Benchmark changes need a look

🟢 0 better · 🔴 5 worse · ⚪ 10 noise (<±5%) · 0 without baseline

Compared against main 50321e4 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	399	0.244	24,044/36,932/36,932 us	🔴 +8.2% / 🔴 +137.1%
🔴	bs=100 sw=10 sl=64	810	0.495	121,866/158,134/158,134 us	🔴 +6.9% / 🔴 +47.5%
🔴	bs=1000 sw=10 sl=64	899	0.548	1,110,559/1,229,182/1,229,182 us	🔴 +5.8% / 🔴 +20.1%

Baseline details

Latest main 50321e4 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	399 tuples/sec	413 tuples/sec	787.98 tuples/sec	-3.4%	-49.4%
bs=10 sw=10 sl=64	MB/s	0.244 MB/s	0.252 MB/s	0.481 MB/s	-3.2%	-49.3%
bs=10 sw=10 sl=64	p50	24,044 us	22,224 us	12,593 us	+8.2%	+90.9%
bs=10 sw=10 sl=64	p95	36,932 us	36,763 us	15,579 us	+0.5%	+137.1%
bs=10 sw=10 sl=64	p99	36,932 us	36,763 us	18,786 us	+0.5%	+96.6%
bs=100 sw=10 sl=64	throughput	810 tuples/sec	833 tuples/sec	1,008 tuples/sec	-2.8%	-19.6%
bs=100 sw=10 sl=64	MB/s	0.495 MB/s	0.509 MB/s	0.615 MB/s	-2.8%	-19.5%
bs=100 sw=10 sl=64	p50	121,866 us	116,799 us	100,701 us	+4.3%	+21.0%
bs=100 sw=10 sl=64	p95	158,134 us	147,868 us	107,244 us	+6.9%	+47.5%
bs=100 sw=10 sl=64	p99	158,134 us	147,868 us	116,122 us	+6.9%	+36.2%
bs=1000 sw=10 sl=64	throughput	899 tuples/sec	909 tuples/sec	1,042 tuples/sec	-1.1%	-13.7%
bs=1000 sw=10 sl=64	MB/s	0.548 MB/s	0.555 MB/s	0.636 MB/s	-1.3%	-13.8%
bs=1000 sw=10 sl=64	p50	1,110,559 us	1,100,624 us	981,959 us	+0.9%	+13.1%
bs=1000 sw=10 sl=64	p95	1,229,182 us	1,161,736 us	1,023,080 us	+5.8%	+20.1%
bs=1000 sw=10 sl=64	p99	1,229,182 us	1,161,736 us	1,051,697 us	+5.8%	+16.9%

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
0,10,10,64,20,500.96,200,128000,399,0.244,24043.72,36932.02,36932.02
1,100,10,64,20,2467.87,2000,1280000,810,0.495,121865.97,158133.72,158133.72
2,1000,10,64,20,22258.91,20000,12800000,899,0.548,1110558.57,1229181.92,1229181.92

[Yicong-Huang]

I am converting this PR to a draft: please follow our PR template and mark it ready for review.

[carloea2]

The description now follows the current template, and this is ready for review.