[ZocoLini]

Part of #1047.

A special payload of a known type in a layout we don't know (a newer version) was decoded with the old layout: the length prefix was read and dropped, so the rest of the block misaligned. #1136 covered unknown types only.

Changes

• Every special payload is read as exactly the bytes its length prefix announces, as Core's GetTxPayload does. The typed payload is kept only if it decodes from all the bytes and re-encodes to them, otherwise the bytes are kept raw. Blocks always decode and txids stay right.
• UnknownPayloadType is renamed RawPayloadType, as it now also holds payloads of known types. get_type() reports the known type.
• TransactionType::consensus_decode alone decides between the typed and the raw payload. A Transaction deserialized through serde or bincode passes a raw payload back to it, so payloads persisted raw by an earlier version decode typed once their layout is known. Its bincode Decode is hand-written for that, with the derived layout.

Breaking: UnknownPayloadType is renamed, and a payload that fails to decode is kept raw instead of failing the transaction.

Testing

• Unit: a ProUpRevTx payload with the known layout decodes typed, with a trailing byte or truncated stays raw, keeps its type, re-encodes to the same bytes and leaves the next transaction aligned; a raw payload of a known layout deserializes typed through JSON, binary serde and bincode.
• cargo test -p dashcore -p key-wallet -p key-wallet-ffi -p key-wallet-manager -p dashcore-rpc-json, clippy -D warnings.

🤖 Generated with Claude Code

PR Hygiene · e760a6a

• Bots — coderabbitai ✓
• Self-review — post /self-reviewed
• Build failed
• Approvals
  • files with no dedicated owner (dash/src/blockdata/transaction/mod.rs, dash/src/blockdata/transaction/special_transaction/mod.rs, key-wallet-ffi/src/special_payload.rs) — QuantumExplorer or xdustinface
  • key-wallet (key-wallet/src/transaction_checking/transaction_router/tests/classification.rs) — QuantumExplorer or xdustinface

When every merge requirement is met, the PR Hygiene check passes. Reviewer limits do not block merging; other required GitHub checks and protections still apply.

Summary by CodeRabbit

• Bug Fixes
  • Special transactions with unrecognized types or payload layouts now retain their original payload data when decoded and re-encoded.
  • Valid payloads for known transaction types are recognized during decoding, including after transactions are saved and reloaded. Truncated, unsupported, or otherwise invalid payload layouts remain preserved as raw data.
  • Transactions with unrecognized special payloads continue to be classified as standard transactions.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Repository: dashpay/rust-dashcore/.coderabbit.yaml
• Review profile: CHILL
• Plan: Advanced
• Run ID: 5c4d8e2c-8519-49fd-9d31-1d3218f3e623

---

📥 Commits

Reviewing files that changed from the base of the PR and between 70bc91e and e760a6a.

---

📒 Files selected for processing (3)

• dash/src/blockdata/transaction/mod.rs
• dash/src/blockdata/transaction/special_transaction/mod.rs
• key-wallet-ffi/src/special_payload.rs

---

Included review availability: This review used your included allowance. Your plan provides up to 1 included review per hour; 0 remain after this review.

---

---

📝 Walkthrough

Walkthrough

Special transaction decoding retains payload bytes when the layout is unsupported or invalid. Transaction deserialization attempts to decode raw payloads as typed payloads. Tests cover valid and malformed layouts, persisted payloads, type zero, and wallet classification.

Changes

Special transaction payload decoding

Layer / File(s)	Summary
Raw payload model and consensus decoding dash/src/blockdata/transaction/special_transaction/mod.rs	RawPayloadType represents unrecognized transaction types and known types with unsupported layouts. Consensus decoding retains payload bytes when decoding fails or does not reproduce the original bytes.
Transaction deserialization and validation dash/src/blockdata/transaction/mod.rs, key-wallet/src/transaction_checking/transaction_router/tests/classification.rs, key-wallet-ffi/src/special_payload.rs	Serde and bincode deserialization attempt to decode raw payloads as typed payloads. Tests cover valid and malformed layouts, persisted payload conversion, and type zero. Wallet classification uses the renamed variant, and FFI documentation allows all provider pointers to be null for raw payloads.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Suggested reviewers: kwvg

---

Merge Risk: ⚪ Minimal · up to e760a

Special payloads with unfamiliar layouts are now kept as raw bytes, so blocks still decode and transaction IDs stay correct. No actionable merge-blocking risk remains. The only breaking change is the rename of the payload variant, which is intentional.

Pre-merge checks | 4 | 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 76.47% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 17 functions across 4 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the primary change: retaining special payloads as raw bytes when their layout is unknown. The breaking-change marker is appropriate because the public enum va…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

---

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 2

📝 Generate docstrings 💡

• Commit to this branch
• Create a new PR

---

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

---

🛠️ Fix failing CI checks 💡

• Commit to this branch
• Create a new PR

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

---

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.}

[github-actions]

Waiting for bot review — coderabbitai not yet. Wait for the missing reviews, or a writer can post /skip-bots to proceed without them; blocking findings still need addressing.
Full checklist in the description.

[github-actions]

Bots are done — your move: post /self-reviewed.
Full checklist in the description.

[codecov]

Codecov Report

❌ Patch coverage is 96.55172% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.60%. Comparing base (2102cac) to head (e760a6a).

Files with missing lines	Patch %	Lines
...c/blockdata/transaction/special_transaction/mod.rs	91.89%	3 Missing ⚠️
dash/src/blockdata/transaction/mod.rs	98.73%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1154      +/-   ##
==========================================
+ Coverage   78.52%   78.60%   +0.07%     
==========================================
  Files         302      302              
  Lines       80413    80505      +92     
==========================================
+ Hits        63147    63279     +132     
+ Misses      17266    17226      -40     

Flag	Coverage Δ
core	77.10% <96.55%> (+0.29%)	⬆️
ffi	51.24% <ø> (+0.14%)	⬆️
rpc	49.36% <ø> (ø)
spv	92.61% <ø> (-0.07%)	⬇️
wallet	82.12% <ø> (ø)

Files with missing lines	Coverage Δ
key-wallet-ffi/src/special_payload.rs	92.60% <ø> (ø)
dash/src/blockdata/transaction/mod.rs	89.73% <98.73%> (+1.31%)	⬆️
...c/blockdata/transaction/special_transaction/mod.rs	51.90% <91.89%> (+6.96%)	⬆️

... and 26 files with indirect coverage changes

[github-actions]

Bots are done — your move: post /self-reviewed.
Full checklist in the description.

[github-actions]

Waiting for bot review — coderabbitai not yet. Wait for the missing reviews, or a writer can post /skip-bots to proceed without them; blocking findings still need addressing.
Full checklist in the description.

[shumkov]

Looks right to me, and it matches what we had in mind on #1047. Re-decoding raw payloads on load is a nice touch we hadn't thought of. A few things, none blocking:

• No test exercises the re-encode check: every case here fails on consumption, not on re-encoding. Two decoders lose information and would reach it. read_fixed_bitset ignores the padding bits of the last byte (consensus/encode.rs:1077), and LLMQType::from(u8) maps an unknown type to LlmqtypeUnknown, which re-encodes as 0 (sml/llmq_type/mod.rs:590). A quorum commitment with a padding bit set, or with an unknown LLMQ type, should stay raw and re-encode to its original bytes.
• key-wallet-ffi/src/special_payload.rs:319-325 documents "Non-null iff payload_type == 1" (and 2-4). A raw ProRegTx now has payload_type == 1 with every pointer null. Worth rewording, even if the API is barely used.

A note for Platform, not for this PR: the change alters which instant asset-lock proof bytes Platform accepts, because a wrong payload length prefix used to be ignored. Platform will take it with a compatibility shim in its bump; we track that on our side.

[github-actions]

Bots are done — your move: address shumkov left a review thread unresolved, then post /self-reviewed.
Full checklist in the description.

[github-actions]

This PR has merge conflicts with the base branch. Please rebase or merge the base branch into your branch to resolve them.

[ZocoLini]

@shumkov all comments addressed, I am merging as soon as CI finishes

[github-actions]

Waiting for bot review — coderabbitai not yet. Wait for the missing reviews, or a writer can post /skip-bots to proceed without them; blocking findings still need addressing.
Full checklist in the description.

[github-actions]

Bots are done — your move: post /self-reviewed.
Full checklist in the description.