AddPack: Extract shared validate-and-register sequence from performGitAdd/performLocalAdd

[bguidolim]

Severity: MEDIUM

performGitAdd and performLocalAdd in PackCommand.swift share a near-identical 5-step sequence:

1. Validate manifest → do/catch → error + throw
2. Load registry → check duplicate → check collisions → collision prompt
3. Display summary → preview bail-out
4. Trust verification → do/catch → guard approved
5. Build PackEntry → register + save → success message

The differences are:

• Git path: has clone/move/temp-cleanup logic, uses fetcher.remove() on failure
• Local path: skips ref, sets isLocal: true, uses localCommitSentinel, no temp cleanup needed

The registry-save block is character-for-character identical. The collision-check and duplicate-check call sites are also structurally identical.

Fix: Extract a shared helper that accepts a closure or strategy for the source-specific bits (clone vs. read-in-place, cleanup on failure).

Found during review of #109.

[bguidolim]

Assessment (2026-03-06)

Still valid?

Yes. The duplication is clearly present. The two methods share 7 nearly identical steps (validate manifest, check duplicate, check collisions, display summary, preview bail-out, trust verification, build+register+save). The registry-save block (L213-220 vs L303-310) is character-for-character identical.

Already partially addressed

The shared helpers (checkDuplicate, checkCollisions, verifyTrust, displayPackSummary) already extract the heavy logic. What remains is orchestration glue — the sequence that calls those helpers — and the registry-save block.

Complexity vs. value

• The full orchestration extraction requires a closure/strategy parameter for cleanup behavior (performGitAdd has 7 separate try? fetcher.remove() calls on error/abort paths), adding indirection for modest gain.
• The registry-save block (7 identical lines) is the strongest candidate — a simple registerAndSave(entry:registryData:ctx:) helper would capture most value with minimal complexity.
• Duplication is well-contained within a single struct (AddPack) in one file — no cross-module spread.

Recommendation

Defer. Suggest downgrading to P3. A partial fix (extracting just the registry-save helper) would be a good low-effort improvement if someone is already working in this area. The full orchestration refactor isn't worth the added indirection right now — no bugs or divergence risk stem from the current state.