feat(key-wallet): track internal address pools for CoinJoin accounts

[ZocoLini]

Summary by CodeRabbit

• New Features

  • CoinJoin accounts now track separate external and internal address pools, matching how addresses are used in practice.
  • Address selection, routing, and transaction checks now recognize both receive and change branches for CoinJoin accounts.

• Bug Fixes

  • Improved address classification so CoinJoin addresses can be identified as external, internal, or other more accurately.
  • FFI access to address pools now returns the correct pool for more account types and scenarios.

[coderabbitai]

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: f929f732-d621-401e-abcf-ccf82c1fc59e

📥 Commits

Reviewing files that changed from the base of the PR and between 2f6e1f7 and 23d0260.

📒 Files selected for processing (10)

• key-wallet-ffi/src/managed_account.rs
• key-wallet-ffi/src/utxo_tests.rs
• key-wallet/src/managed_account/managed_account_collection.rs
• key-wallet/src/managed_account/managed_account_trait.rs
• key-wallet/src/managed_account/managed_account_type.rs
• key-wallet/src/tests/account_tests.rs
• key-wallet/src/transaction_checking/account_checker.rs
• key-wallet/src/transaction_checking/transaction_router/tests/conversions.rs
• key-wallet/src/transaction_checking/transaction_router/tests/routing.rs
• key-wallet/src/transaction_checking/wallet_checker.rs

📝 Walkthrough

Walkthrough

ManagedAccountType::CoinJoin is changed from holding a single addresses pool to holding separate external_addresses (child index 0) and internal_addresses (child index 1) pools. This struct change is propagated through pool accessors, trait methods, address classification, the FFI address-pool selector, and all affected tests.

Changes

CoinJoin Dual-Pool Refactor

Layer / File(s)	Summary
CoinJoin variant: dual-pool struct definition and pool accessors key-wallet/src/managed_account/managed_account_type.rs	Redefines ManagedAccountType::CoinJoin with external_addresses and internal_addresses fields. Updates address_pools, address_pools_mut, and from_account_type to derive two pools from child indices 0 and 1 and return both.
Trait methods and collection derivation updated for dual pools key-wallet/src/managed_account/managed_account_collection.rs, key-wallet/src/managed_account/managed_account_trait.rs	ManagedAccountCollection::build_managed_account_type now derives both pools for CoinJoin. Four ManagedAccountTrait default-method match arms (get_next_address_index, next_address, next_address_with_info, gap_limit) bind addresses from external_addresses.
Address classification and FFI pool selection for CoinJoin key-wallet/src/transaction_checking/account_checker.rs, key-wallet-ffi/src/managed_account.rs	classify_address merges the CoinJoin match arm with Standard, enabling Internal classification. FFI managed_core_account_get_address_pool now serves External/Internal pool types for both Standard and CoinJoin, and the FFIAddressPool wrapper is constructed once at the match end.
Test fixtures updated to dual-pool CoinJoin key-wallet/src/tests/account_tests.rs, key-wallet/src/transaction_checking/transaction_router/tests/conversions.rs, key-wallet/src/transaction_checking/transaction_router/tests/routing.rs, key-wallet/src/transaction_checking/wallet_checker.rs, key-wallet-ffi/src/utxo_tests.rs	All test fixtures and destructuring patterns updated to construct ManagedAccountType::CoinJoin with external_addresses and internal_addresses, and to derive addresses from external_addresses.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• dashpay/rust-dashcore#804: Introduced configurable CoinJoin gap limits and modified ManagedAccountType::from_account_type CoinJoin derivation, which is the same code path this PR extends with dual-pool support.

Suggested labels

ready-for-review

Suggested reviewers

• xdustinface

🐇 Two pools now bloom where once was one,
External and internal, derivation done!
CoinJoin hops down both branch 0 and 1,
Addresses sorted beneath a clear sun.
The rabbit rejoices — dual pools have won! 🌿

🚥 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 summarizes the main change: CoinJoin accounts now track internal address pools.
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 unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/coinjoin-external

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

key-wallet/src/managed_account/managed_account_collection.rs (1)

588-613: 📐 Maintainability & Code Quality | 🔵 Trivial | 🏗️ Heavy lift

Consolidate CoinJoin pool construction into one helper.

This branch now duplicates the same dual-pool CoinJoin build logic in ManagedAccountType::from_account_type, and those two constructors have already drifted in adjacent Standard-path error handling. Keeping both copies in sync is going to be fragile. Extract the pool-building logic once and have both call sites delegate to it.

🤖 Prompt for 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.

In `@key-wallet/src/managed_account/managed_account_collection.rs` around lines
588 - 613, The CoinJoin dual-pool construction logic is duplicated and should be
centralized to avoid future drift. Extract the shared external/internal
AddressPool setup into a single helper used by
ManagedAccountType::from_account_type and the other CoinJoin constructor path,
keeping the base_path cloning, ChildNumber indices, AddressPoolType values, gap
limit, network, and key_source wiring in one place.

🤖 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 `@key-wallet/src/transaction_checking/account_checker.rs`:
- Around line 559-563: The CoinJoin address matching flow is now classifying
internal addresses, but they are not included in the returned payload. Update
the CoinJoin branch in account_checker.rs, specifically the
ManagedAccountType::CoinJoin handling and the CoreAccountTypeMatch::CoinJoin
builder, so the internal_addresses collection is carried through and merged
alongside the receive/other addresses instead of being dropped. Verify the
returned CoinJoin match data includes external, internal, and any other
classified addresses consistently.

---

Nitpick comments:
In `@key-wallet/src/managed_account/managed_account_collection.rs`:
- Around line 588-613: The CoinJoin dual-pool construction logic is duplicated
and should be centralized to avoid future drift. Extract the shared
external/internal AddressPool setup into a single helper used by
ManagedAccountType::from_account_type and the other CoinJoin constructor path,
keeping the base_path cloning, ChildNumber indices, AddressPoolType values, gap
limit, network, and key_source wiring in one place.

🪄 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: 219b56cf-621c-400d-82dd-d66c78cf142f

📥 Commits

Reviewing files that changed from the base of the PR and between d9fe0a3 and 2f6e1f7.

📒 Files selected for processing (10)

• key-wallet-ffi/src/managed_account.rs
• key-wallet-ffi/src/utxo_tests.rs
• key-wallet/src/managed_account/managed_account_collection.rs
• key-wallet/src/managed_account/managed_account_trait.rs
• key-wallet/src/managed_account/managed_account_type.rs
• key-wallet/src/tests/account_tests.rs
• key-wallet/src/transaction_checking/account_checker.rs
• key-wallet/src/transaction_checking/transaction_router/tests/conversions.rs
• key-wallet/src/transaction_checking/transaction_router/tests/routing.rs
• key-wallet/src/transaction_checking/wallet_checker.rs

[codecov]

Codecov Report

❌ Patch coverage is 69.56522% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.01%. Comparing base (d9fe0a3) to head (23d0260).

Files with missing lines	Patch %	Lines
key-wallet-ffi/src/managed_account.rs	30.43%	16 Missing ⚠️
...allet/src/managed_account/managed_account_trait.rs	25.00%	3 Missing ⚠️
.../src/managed_account/managed_account_collection.rs	92.85%	1 Missing ⚠️
...wallet/src/managed_account/managed_account_type.rs	95.23%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #821      +/-   ##
==========================================
- Coverage   73.04%   73.01%   -0.03%     
==========================================
  Files         323      323              
  Lines       72046    72064      +18     
==========================================
- Hits        52623    52619       -4     
- Misses      19423    19445      +22     

Flag	Coverage Δ
core	76.74% <ø> (ø)
ffi	47.35% <30.43%> (-0.01%)	⬇️
rpc	20.00% <ø> (ø)
spv	90.17% <ø> (-0.14%)	⬇️
wallet	71.85% <89.13%> (+0.02%)	⬆️

Files with missing lines	Coverage Δ
...wallet/src/transaction_checking/account_checker.rs	53.98% <100.00%> (-0.05%)	⬇️
...-wallet/src/transaction_checking/wallet_checker.rs	99.22% <100.00%> (+<0.01%)	⬆️
.../src/managed_account/managed_account_collection.rs	58.83% <92.85%> (+0.34%)	⬆️
...wallet/src/managed_account/managed_account_type.rs	41.29% <95.23%> (+1.62%)	⬆️
...allet/src/managed_account/managed_account_trait.rs	36.80% <25.00%> (ø)
key-wallet-ffi/src/managed_account.rs	63.52% <30.43%> (+0.08%)	⬆️

... and 7 files with indirect coverage changes