refactor(sort): rename SpillCompress → SpillBlockCompress to disambiguate from CompressSpill

[nh13]

What

Two distinct spill-compression steps had confusable, word-swapped names:

• CompressSpill (chunk-granularity) — compresses a whole sorted chunk and writes the spill file, in the P6 Phase-1 split (SortBuffer → CompressSpill → SortSpillDecompress → SortMerge).
• SpillCompress (block-granularity) — compresses one raw SpillBlockEvent::Block in place (no file write; SpillWrite writes), in the block-parallel split (SpillGather → SpillCompress → SpillWrite).

They do different things, but the near-mirrored names invited mix-ups. Rename the block-parallel step to SpillBlockCompress (and its module/file to spill_block_compress), which reads naturally against the SpillBlockCompressor kernel it drives and the SpillBlockEvent::Block it consumes.

Notes

• Pure rename, no behavior change. fgumi-pipeline-io/fgumi-sort are feat-runall-only, so no main-reconcile conflict. Targets nh/audit-3-parity.

Verification

cargo ci-test 2332 passed; cargo ci-lint clean.

Summary by CodeRabbit

• New Features

  • Updated the sorting pipeline to use block-level spill compression, enabling clearer separation between compression and disk writing.
  • Renamed the spill compression stage to better reflect its block-oriented behavior.

• Documentation

  • Updated pipeline descriptions and inline documentation to reflect the revised processing stages.

• Tests

  • Expanded coverage to verify compressed block metadata, residual event passthrough, and clone behavior.

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📥 Commits

Reviewing files that changed from the base of the PR and between 6362996 and 37b6451.

📒 Files selected for processing (14)

• crates/fgumi-pipeline-io/src/sort/compress_spill.rs
• crates/fgumi-pipeline-io/src/sort/mod.rs
• crates/fgumi-pipeline-io/src/sort/protocol.rs
• crates/fgumi-pipeline-io/src/sort/spill_block_compress.rs
• crates/fgumi-pipeline-io/src/sort/spill_block_compress/tests.rs
• crates/fgumi-pipeline-io/src/sort/spill_gather.rs
• crates/fgumi-pipeline-io/src/sort/spill_write.rs
• crates/fgumi-pipeline-io/src/sort/spill_write/tests.rs
• crates/fgumi-sort/src/lib.rs
• crates/fgumi-sort/src/spill_block.rs
• src/lib/pipeline/chains/build.rs
• src/lib/pipeline/chains/builder.rs
• src/lib/pipeline/chains/commands/sort.rs
• src/lib/pipeline/steps/sort/mod.rs

---

Walkthrough

The spill compression stage is renamed from SpillCompress to SpillBlockCompress, with updated exports, pipeline construction, tests, profiling names, and documentation. Compression and event pass-through behavior remain unchanged.

Changes

SpillBlockCompress stage

Layer / File(s)	Summary
Compressor rename and behavior validation crates/fgumi-pipeline-io/src/sort/spill_block_compress.rs, crates/fgumi-pipeline-io/src/sort/spill_block_compress/tests.rs	Renames the public step and profile name, while tests verify block compression, metadata preservation, pass-through events, and clone initialization.
Public exports and pipeline wiring crates/fgumi-pipeline-io/src/sort/mod.rs, src/lib/pipeline/steps/sort/mod.rs, src/lib/pipeline/chains/builder.rs	Replaces SpillCompress exports and constructs SpillBlockCompress in the sort pipeline.
Pipeline documentation alignment crates/fgumi-pipeline-io/src/sort/*.rs, crates/fgumi-sort/src/*.rs, src/lib/pipeline/chains/*.rs, src/lib/pipeline/chains/commands/sort.rs	Updates spill-stage descriptions and topology comments to use SpillBlockCompress.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• fulcrumgenomics/fgumi#474: Introduced the original SpillCompress spill-chain implementation that this change renames and refines.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	Accurately summarizes the main change: renaming SpillCompress to SpillBlockCompress to distinguish it from CompressSpill.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch nh/audit-f-spillcompress-rename

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Additional details and impacted files

@@              Coverage Diff               @@
##             feat-runall     #557   +/-   ##
==============================================
  Coverage               ?   94.22%           
==============================================
  Files                  ?      111           
  Lines                  ?    50988           
  Branches               ?        0           
==============================================
  Hits                   ?    48045           
  Misses                 ?     2943           
  Partials               ?        0           

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[nh13]

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