feat(core): cap over-long phrase segments at MAX_PHRASE_BARS (#76, part 1)

[PhysShell]

First of three slices for #76 (phrase-segmentation quality). This one tackles the over-long phrases — the playtest's "30+ bar phrases that don't fit a single rhythmic pattern."

What

• New pure helper cap_segment_bars(segments, max_bars) in core/src/split.rs: subdivides any segment longer than the cap into consecutive ≤max_bars sub-ranges, leaving shorter ones intact. Composes after bar_segments (only adds cuts; still sorted, non-overlapping, full coverage).
• MAX_PHRASE_BARS = 16 default cap (generous — splits only clearly over-long phrases; documented as tunable).
• Both split paths apply it: web/src/lib.rs (split_to_json) and cli/src/main.rs (phrase_chunks).

Approach

Genuine red → green (this is core algorithm, not glue): 14f48a7 adds failing tests + an unimplemented!() stub; 52a1789 implements it and wires the callers.

Verification

• core split tests 8/8 (4 new cap cases: zero-cap passthrough, within-cap whole, over-long split + remainder, exact multiple, per-segment independence); cli green; clippy -D warnings clean.
• End-to-end (rebuilt wasm + DGD GPX): every phrase span is ≤ 16 bars, no page errors.

Honest note on scope

On the DGD guitar track the longest detected phrase is 12 bars, so the cap is a safety net there rather than a visible change — it enforces the invariant and kicks in on the longer-phrased material the playtest hit. The genuinely-visible junk on that track is the two 1-bar phrases, which is the issue's trivial-phrase part — coming next as part 2 (a min-bars/min-notes drop). Novelty dedup is part 3.

🤖 Generated with Claude Code

https://claude.ai/code/session_01TTUbGjzD8ysnVnCJnZJE95

---

Generated by Claude Code

Summary by CodeRabbit

Release Notes

• Improvements
  • Enhanced griff split phrase curation to automatically cap over-long phrases exceeding 16 bars into smaller segments. This prevents excessively long phrases from being processed as single chunks, improving curation performance and reliability.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: e6a6d388-9511-45cf-9cdc-1b20575d0be5

📥 Commits

Reviewing files that changed from the base of the PR and between dea284a and 52a1789.

📒 Files selected for processing (3)

• cli/src/main.rs
• core/src/split.rs
• web/src/lib.rs

---

📝 Walkthrough

Walkthrough

core/src/split.rs gains a MAX_PHRASE_BARS constant (16) and a cap_segment_bars function that subdivides bar-range segments exceeding a given maximum into consecutive sub-ranges. Both the CLI (phrase_chunks) and web (split_to_json) auto-split paths are updated to wrap their bar_segments output with cap_segment_bars(MAX_PHRASE_BARS).

Changes

Phrase segment bar-length capping

Layer / File(s)	Summary
MAX_PHRASE_BARS constant and cap_segment_bars implementation core/src/split.rs	Defines MAX_PHRASE_BARS = 16 with documentation, adds cap_segment_bars that splits over-length segments into consecutive sub-ranges (early-returning when max_bars == 0), and adds unit tests covering disabled cap, within-cap, over-long, exact-multiple, non-zero offset, and multi-segment cases.
CLI and web integration cli/src/main.rs, web/src/lib.rs	Imports cap_segment_bars and MAX_PHRASE_BARS and wraps the bar_segments(...) call with cap_segment_bars(..., MAX_PHRASE_BARS) in both phrase_chunks and split_to_json.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related issues

• engine/curation: phrase segmentation — dedup repeats, drop trivial, split over-long phrases #76: This PR directly implements the over-long phrase capping requirement described in that issue by introducing MAX_PHRASE_BARS and cap_segment_bars.

Possibly related PRs

• PhysShell/griff#70: Introduced the phrase-splitting pipeline in cli/src/main.rs around bar_segments that this PR extends with bar-length capping.
• PhysShell/griff#71: Modified the web split_to_json bar-segmentation path that this PR also updates to add cap_segment_bars.

Poem

🐇 Hoppin' through the bars, one-two-three,
No phrase too long shall escape from me!
Sixteen bars max, then snip-snip-snip,
cap_segment_bars keeps phrases crisp.
The rabbit cheers — a tidy split! 🎵

🚥 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	The title clearly and specifically describes the main change: introducing phrase segment capping at MAX_PHRASE_BARS, and correctly contextualizes it as part 1 of a multi-part effort (#76).
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ 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 claude/modest-maxwell-0zecwn

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}