fix(editor): a drum edit no longer strips authored keys from drum-part manifest entries

[ChrisBeWithYou]

What

Closes a data-loss window opened by feedpak-spec 1.18.0 (spec #62, merged today): a type: "drums" arrangement entry can now carry a per-arrangement tones sound binding — but the editor's /save_song drum block rebuilds every drum-pointer entry from scratch as {id, name, type, drum_tab} on any drum-dirty save. Edit the drums in a pack whose entries carry tones (or any extension key), hit Save, and the binding silently vanished.

The fix

The rebuild now merges each entry onto its prior same-id entry through the existing _merge_manifest_entry — the exact unknown-key preservation rule the pitched pipeline has followed since the merge-not-rebuild save (#101). Semantics:

• authored/additive keys (tones, extension keys) survive verbatim;
• the editor-owned keys (id/name/type/drum_tab) always take the rebuilt value;
• no predecessor (a new part, or an id that changed) → exactly the clean four-key entry, so single-drum packs stay byte-identical with pre-1.18.0 saves.

Extracted as module-level _drum_pointer_entry (used at both the primary-alias and extra-part sites), mirroring how the create-mode twin _create_build_drum_entries is pinned. Create mode builds fresh packs with no prior manifest — nothing to preserve, untouched. The absent-drum_parts branch already re-appends prior entries verbatim, so old clients were never the problem.

Spec cross-refs: 1.18.0 §5.2 entry tones; the §5.1 drum_tones/entry-tones precedence rule (top-level drum_tones was never at risk — the save merges the manifest top level rather than rebuilding it).

Tests

tests/test_drum_parts.py +3 (suite 14/14; the import fails on main where the helper doesn't exist):

• tones + an extension key survive a rebuild while name/drum_tab take the new values; the prior entry object is never mutated
• no predecessor → exactly the clean entry (byte-identical guarantee)
• malformed predecessor contributes nothing rather than crashing the save

Full gates: pytest 381/0, npm run lint 0 errors, npm test 303/305 (the 2 failures pre-exist on main).

🤖 Generated with Claude Code

https://claude.ai/code/session_017xGPjDBF8NTwTK7VQvizix

Summary by CodeRabbit

• Bug Fixes
  • Drum edits now preserve additional arrangement metadata and extension fields when saving.
  • Editor-managed drum fields continue to update correctly while unrelated authored keys remain intact.
  • Saving safely handles missing or malformed prior drum entries without errors.

[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: 4f168537-ae76-4bd0-9ffd-760e88959862

📥 Commits

Reviewing files that changed from the base of the PR and between f976f91 and 22ba8fe.

📒 Files selected for processing (3)

• CHANGELOG.md
• routes.py
• tests/test_drum_parts.py

---

📝 Walkthrough

Walkthrough

Drum arrangement pointer entries rebuilt during save now preserve prior additive keys while replacing editor-owned fields. The change adds a merge helper, integrates it into primary and extra drum pointer reconstruction, adds regression tests, and documents the fix.

Changes

Drum manifest preservation

Layer / File(s)	Summary
Drum pointer merge helper routes.py, tests/test_drum_parts.py	_drum_pointer_entry merges rebuilt core fields onto valid predecessors, falls back cleanly for missing or malformed predecessors, and is covered by regression tests.
Save rebuild integration routes.py, CHANGELOG.md	The drum-parts save path matches prior pointer entries by ID and applies merged rebuilding to primary and extra drum pointers; the fix is documented.
Estimated code review effort: 2 (Simple)	~10 minutes

Possibly related PRs

• got-feedBack/feedBack-plugin-editor#101: Updates save logic to preserve previously authored manifest fields when rebuilding entries.

Suggested reviewers: byrongamatos

🚥 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 summarizes the main change: preserving authored keys in drum-part manifest entries during drum edits.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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 drum-entry-key-preserve

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

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