fix(drive): accept MMR-aligned shielded note proof ranges

[llbartekll]

Summary

• validate shielded encrypted-note proof resume offsets against the on-chain MMR chunk size instead of the multi-chunk request limit
• add a proof-based regression test for start index 2048 with an 8192-element request cap

Context

Wallet sync rewinds its encrypted-note watermark to a 2048-note MMR chunk boundary, while one request may fetch four chunks. The verifier previously treated the 8192-element request limit as the alignment unit and rejected the valid 2048 resume point, leaving shielded sync and balance recovery stuck.

Validation

• cargo fmt --package drive -- --check
• cargo test -p drive accepts_mmr_aligned_start_inside_multi_chunk_query_boundary --lib
• ./packages/swift-sdk/build_ios.sh --target ios --target sim
• xcodebuild dashwallet-dashpay Debug for arm64 iOS Simulator

Summary by CodeRabbit

• Bug Fixes
  • Improved shielded notes verification when resuming from multi-chunk queries.
  • Resume points are now validated against the correct MMR chunk boundaries (not element-count alignment).
  • Added safety to prevent index overflow during range calculations, returning a clear corruption error when invalid.
• Tests
  • Added coverage for aligned resume points inside multi-chunk requests.
  • Added coverage for rejecting chunk-aligned start points near the maximum index with the expected error.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: d5909da3-b642-4d9e-88b3-ea00392924d2

📥 Commits

Reviewing files that changed from the base of the PR and between 8e680ab and 1fd481e.

📒 Files selected for processing (1)

• packages/rs-drive/src/verify/shielded/verify_shielded_encrypted_notes/v0/mod.rs

---

📝 Walkthrough

Walkthrough

The shielded encrypted notes verifier now aligns start_index to MMR chunk boundaries and uses checked arithmetic for inclusive range ends. Tests cover aligned resumes within multi-chunk requests and overflow rejection near u64::MAX.

Changes

Shielded notes verification

Layer / File(s)	Summary
MMR-aligned resume validation packages/rs-drive/src/verify/shielded/verify_shielded_encrypted_notes/v0/mod.rs	Resume validation uses the MMR chunk size, with coverage for aligned positions inside multi-chunk requests and correct total_count extraction.
Query range overflow protection packages/rs-drive/src/verify/shielded/verify_shielded_encrypted_notes/v0/mod.rs	Inclusive end-index calculation now fails with a corruption error when the range exceeds u64::MAX, covered by a boundary test.

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

Possibly related PRs

• dashpay/platform#3756: Updates related shielded encrypted notes v0 alignment validation and tests.

Suggested reviewers: shumkov, quantumexplorer

🚥 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 accurately reflects the main change: accepting MMR-aligned shielded note proof ranges.
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 codex/fix-shielded-proof-chunk-alignment

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[thepastaclaw]

🕓 Ready for review — 1 ahead in queue (commit 8e680ab)
Queue position: 2/24 · 2 reviews active
ETA: start ~05:41 UTC · complete ~06:02 UTC (median 21m across 30 recent reviews; 2 slots)
Queued 15h 53m ago · Last checked: 2026-07-23 05:20 UTC

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In
`@packages/rs-drive/src/verify/shielded/verify_shielded_encrypted_notes/v0/mod.rs`:
- Around line 47-54: In the shielded notes verification flow around the
start_index alignment check and PathQuery construction, validate the inclusive
end index with checked arithmetic using start_index and limit - 1. If the
addition overflows, return the existing Drive corruption error before
constructing the PathQuery; otherwise use the checked result for the query
range.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 45f7a606-a0fa-4a43-b1b8-dea16c66b770

📥 Commits

Reviewing files that changed from the base of the PR and between 267e1cb and 8e680ab.

📒 Files selected for processing (1)

• packages/rs-drive/src/verify/shielded/verify_shielded_encrypted_notes/v0/mod.rs

[codecov]

Codecov Report

❌ Patch coverage is 95.91837% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.51%. Comparing base (552abfc) to head (1fd481e).
⚠️ Report is 18 commits behind head on v4.1-dev.

Files with missing lines	Patch %	Lines
...shielded/verify_shielded_encrypted_notes/v0/mod.rs	95.91%	2 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##           v4.1-dev    #4201       +/-   ##
=============================================
+ Coverage     65.42%   87.51%   +22.09%     
=============================================
  Files            26     2666     +2640     
  Lines          2707   336911   +334204     
=============================================
+ Hits           1771   294844   +293073     
- Misses          936    42067    +41131     

Components	Coverage Δ
dpp	88.47% <ø> (∅)
drive	86.24% <95.91%> (∅)
drive-abci	89.58% <ø> (∅)
sdk	∅ <ø> (∅)
dapi-client	∅ <ø> (∅)
platform-version	∅ <ø> (∅)
platform-value	92.90% <ø> (∅)
platform-wallet	∅ <ø> (∅)
drive-proof-verifier	49.79% <ø> (∅)

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