chore(amber): remove the unused ElidableStatement

[aglinxinyuan]

What changes were proposed in this PR?

Deletes ElidableStatement and its spec. Pure deletion, no behaviour change: −175 lines.

The object wraps statements in scala.annotation.elidable so they can be compiled out below a threshold. That threshold comes from the -Xelide-below scalac option, which appears in no build.sbt in this repo — so the wrapper had no effect even in principle. A case-insensitive search for elidable across all Scala and sbt sources returns only the object and its own spec; nothing calls it.

Reviewer note: it acquired unit tests during the 2026 coverage work, which is why it currently looks live. The spec covers this object and nothing else, so it goes with it.

Any related issues, documentation, discussions?

Closes #7448

How was this PR tested?

Existing tests only — this PR adds none, since it removes code and the spec that covered it.

Locally, from the repo root with Java 17:

• sbt "WorkflowExecutionService/Test/compile" — success.

Verification, re-runnable by a reviewer:

git grep -in elidable          # only the two deleted files

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

Generated-by: Claude Code (Claude Opus 5)

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⚠️ Benchmark changes need a look

🟢 4 better · 🔴 1 worse · ⚪ 10 noise (<±5%) · 0 without baseline

Compared against main e03d971 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	429	0.262	22,854/31,269/31,269 us	🔴 +22.1% / 🔴 +94.0%
🟢	bs=100 sw=10 sl=64	948	0.578	104,313/125,771/125,771 us	🟢 -17.2% / 🔴 +13.1%
⚪	bs=1000 sw=10 sl=64	1,110	0.677	895,992/984,290/984,290 us	⚪ within ±5% / 🟢 +12.8%

Baseline details

Latest main e03d971 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	429 tuples/sec	442 tuples/sec	752.25 tuples/sec	-2.9%	-43.0%
bs=10 sw=10 sl=64	MB/s	0.262 MB/s	0.27 MB/s	0.459 MB/s	-3.0%	-42.9%
bs=10 sw=10 sl=64	p50	22,854 us	18,712 us	13,006 us	+22.1%	+75.7%
bs=10 sw=10 sl=64	p95	31,269 us	37,382 us	16,117 us	-16.4%	+94.0%
bs=10 sw=10 sl=64	p99	31,269 us	37,382 us	19,286 us	-16.4%	+62.1%
bs=100 sw=10 sl=64	throughput	948 tuples/sec	973 tuples/sec	953.66 tuples/sec	-2.6%	-0.6%
bs=100 sw=10 sl=64	MB/s	0.578 MB/s	0.594 MB/s	0.582 MB/s	-2.7%	-0.7%
bs=100 sw=10 sl=64	p50	104,313 us	99,986 us	105,130 us	+4.3%	-0.8%
bs=100 sw=10 sl=64	p95	125,771 us	151,855 us	111,226 us	-17.2%	+13.1%
bs=100 sw=10 sl=64	p99	125,771 us	151,855 us	121,065 us	-17.2%	+3.9%
bs=1000 sw=10 sl=64	throughput	1,110 tuples/sec	1,140 tuples/sec	984.25 tuples/sec	-2.6%	+12.8%
bs=1000 sw=10 sl=64	MB/s	0.677 MB/s	0.696 MB/s	0.601 MB/s	-2.7%	+12.7%
bs=1000 sw=10 sl=64	p50	895,992 us	868,196 us	1,024,295 us	+3.2%	-12.5%
bs=1000 sw=10 sl=64	p95	984,290 us	945,887 us	1,062,710 us	+4.1%	-7.4%
bs=1000 sw=10 sl=64	p99	984,290 us	945,887 us	1,095,400 us	+4.1%	-10.1%

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
0,10,10,64,20,465.99,200,128000,429,0.262,22853.77,31269.09,31269.09
1,100,10,64,20,2110.69,2000,1280000,948,0.578,104312.74,125770.80,125770.80
2,1000,10,64,20,18020.52,20000,12800000,1110,0.677,895991.78,984290.20,984290.20

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.32%. Comparing base (e03d971) to head (fcadde7).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #7451      +/-   ##
============================================
- Coverage     85.32%   85.32%   -0.01%     
+ Complexity     4151     4149       -2     
============================================
  Files          1169     1168       -1     
  Lines         46740    46739       -1     
  Branches       5202     5202              
============================================
- Hits          39882    39880       -2     
+ Misses         5148     5147       -1     
- Partials       1710     1712       +2     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.00% <ø> (ø)		Carriedforward from e03d971
agent-service	85.50% <ø> (ø)		Carriedforward from e03d971
amber	80.88% <ø> (-0.01%)	⬇️
computing-unit-managing-service	50.72% <ø> (ø)		Carriedforward from e03d971
config-service	65.97% <ø> (ø)		Carriedforward from e03d971
file-service	69.05% <ø> (ø)		Carriedforward from e03d971
frontend	87.85% <ø> (ø)		Carriedforward from e03d971
notebook-migration-service	78.89% <ø> (ø)		Carriedforward from e03d971
pyamber	97.51% <ø> (ø)		Carriedforward from e03d971
workflow-compiling-service	26.31% <ø> (ø)		Carriedforward from e03d971

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

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[Yicong-Huang]

🔴 1 must-fix · 1 advisory · 0 polish — the deletion is correct and well-scoped; what needs fixing is the justification it merges under.

Conventions (1)

• The description and #7448 state -Xelide-below is configured nowhere; sixteen modules set it to WARNING (must-fix). Rest both on the sufficient ground — no caller — and verify with git grep -in elide, not elidable.

Simplifications (1)

• No @elidable annotation remains after this PR, so -Xelide-below WARNING documents a switch over nothing (advisory) — a follow-up, since it sits in sixteen build files.

Verification trace

Traced whether the elision was ever live, since the PR argues it was not: git grep -n Xelide -- '*.sbt' returns sixteen modules pinned at WARNING (900), and all four wrapper levels (300–800) sit below it, so every call site was compiled out. That is exactly what the deleted spec pinned — assert(counter == 0) after ElidableStatement.info { counter += 1 } is satisfiable only under elision. The deletion survives the correction intact: git grep -n ElidableStatement returns nothing at the head, so no referent is left dangling.