fix(amber): preserve evaluated values

[carloea2]

What changes were proposed in this PR?

Add the worker's EvaluatedValue reply to the generic ControlReturn transport. This prevents evaluated Python expression results from being replaced by an empty return before they reach the coordinator.

Any related issues, documentation, discussions?

Closes #8235

How was this PR tested?

python -c "import sys,pytest; sys.path[:0]=[worktree amber source]; raise SystemExit(pytest.main(['amber/src/test/python/core/architecture/rpc/test_async_rpc_handler_initializer.py','amber/src/test/python/core/architecture/rpc/test_async_rpc_server.py','amber/src/test/python/core/architecture/handlers/control/test_evaluate_expression_handler.py','-q','-p','no:cacheprovider']))"
81 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

The Python protobuf bindings were regenerated from the changed descriptor for verification and remain ignored as required by the repository. A direct post-fix transport probe produced:

packed_type=EvaluatedValue
packed_value=42
round_trip=True

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

Generated-by: Codex

[github-actions]

👋 Thanks for opening this pull request, @carloea2!

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[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/protobuf/org/apache/texera/amber/engine/architecture/rpc/controlreturns.proto, amber/src/test/python/core/architecture/rpc/test_async_rpc_handler_initializer.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: @Yicong-Huang, @eugenegujing
  You can notify them by mentioning @Yicong-Huang, @eugenegujing in a comment.

[github-actions]

⚠️ Benchmark changes need a look

🟢 2 better · 🔴 3 worse · ⚪ 10 noise (<±5%) · 0 without baseline

Compared against main 8aea604 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	378	0.231	25,157/35,389/35,389 us	🔴 +7.6% / 🔴 +122.5%
🟢	bs=100 sw=10 sl=64	803	0.49	121,637/150,396/150,396 us	🟢 -19.8% / 🔴 +35.9%
⚪	bs=1000 sw=10 sl=64	931	0.568	1,068,781/1,118,944/1,118,944 us	⚪ within ±5% / 🔴 -6.3%

Baseline details

Latest main 8aea604 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	378 tuples/sec	406 tuples/sec	750.65 tuples/sec	-6.9%	-49.6%
bs=10 sw=10 sl=64	MB/s	0.231 MB/s	0.248 MB/s	0.458 MB/s	-6.9%	-49.6%
bs=10 sw=10 sl=64	p50	25,157 us	23,371 us	13,049 us	+7.6%	+92.8%
bs=10 sw=10 sl=64	p95	35,389 us	35,844 us	15,902 us	-1.3%	+122.5%
bs=10 sw=10 sl=64	p99	35,389 us	35,844 us	19,184 us	-1.3%	+84.5%
bs=100 sw=10 sl=64	throughput	803 tuples/sec	801 tuples/sec	960.3 tuples/sec	+0.2%	-16.4%
bs=100 sw=10 sl=64	MB/s	0.49 MB/s	0.489 MB/s	0.586 MB/s	+0.2%	-16.4%
bs=100 sw=10 sl=64	p50	121,637 us	118,044 us	104,199 us	+3.0%	+16.7%
bs=100 sw=10 sl=64	p95	150,396 us	187,427 us	110,645 us	-19.8%	+35.9%
bs=100 sw=10 sl=64	p99	150,396 us	187,427 us	120,888 us	-19.8%	+24.4%
bs=1000 sw=10 sl=64	throughput	931 tuples/sec	931 tuples/sec	993.27 tuples/sec	0.0%	-6.3%
bs=1000 sw=10 sl=64	MB/s	0.568 MB/s	0.568 MB/s	0.606 MB/s	0.0%	-6.3%
bs=1000 sw=10 sl=64	p50	1,068,781 us	1,073,110 us	1,012,191 us	-0.4%	+5.6%
bs=1000 sw=10 sl=64	p95	1,118,944 us	1,139,031 us	1,054,057 us	-1.8%	+6.2%
bs=1000 sw=10 sl=64	p99	1,118,944 us	1,139,031 us	1,081,313 us	-1.8%	+3.5%

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
0,10,10,64,20,528.58,200,128000,378,0.231,25156.55,35388.60,35388.60
1,100,10,64,20,2490.41,2000,1280000,803,0.490,121636.81,150395.63,150395.63
2,1000,10,64,20,21473.82,20000,12800000,931,0.568,1068780.61,1118943.92,1118943.92

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.68%. Comparing base (8aea604) to head (66a6ac5).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8236      +/-   ##
============================================
+ Coverage     94.07%   95.68%   +1.60%     
+ Complexity     4809     2870    -1939     
============================================
  Files          1194      930     -264     
  Lines         48597    39931    -8666     
  Branches       5857     4680    -1177     
============================================
- Hits          45718    38208    -7510     
+ Misses         1428      891     -537     
+ Partials       1451      832     -619     

Flag	Coverage Δ		*Carryforward flag
access-control-service	81.00% <ø> (ø)		Carriedforward from 8aea604
agent-service	99.32% <ø> (ø)		Carriedforward from 8aea604
amber	93.45% <ø> (+3.34%)	⬆️
computing-unit-managing-service	73.67% <ø> (ø)		Carriedforward from 8aea604
config-service	87.00% <ø> (ø)		Carriedforward from 8aea604
file-service	87.91% <ø> (ø)		Carriedforward from 8aea604
frontend	96.82% <ø> (ø)		Carriedforward from 8aea604
notebook-migration-service	79.31% <ø> (ø)		Carriedforward from 8aea604
pyamber	98.18% <ø> (ø)
workflow-compiling-service	77.19% <ø> (ø)		Carriedforward from 8aea604

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

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[carloea2]

Amber failed in TexeraWebSocketEventSpec after the ActorSystem shutdown error. PyAmber and both Amber integration jobs passed. I cannot rerun repository jobs as a contributor. Could someone rerun Amber?

[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.