fix(wallet): serialize mixing-only lock state

[PastaPastaPasta]

Issue being fixed or feature implemented

CWallet::Lock(true) updated the mixing-only lock flag without holding cs_wallet, while Unlock() updated the same flag under the mutex. IsLocked() could also read the flag before acquiring the mutex. Concurrent wallet lock transitions could therefore race and expose an inconsistent lock state.

What was done?

• Guard fOnlyMixingAllowed with cs_wallet and annotate that invariant.
• Serialize both reads and all lock transitions through the wallet mutex.

No release note is included because this is an internal synchronization fix with no interface or workflow change.

How Has This Been Tested?

Built on Apple Silicon with the depends toolchain using --without-gui --disable-bench, then ran:

• make -j13
• ./src/test/test_dash --run_test=wallet_tests --log_level=message
• test/lint/all-lint.py
• git clang-format --diff upstream/develop -- src/wallet/wallet.cpp src/wallet/wallet.h

Breaking Changes

None.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests (not applicable; guarded by Clang thread-safety analysis)
• I have made corresponding changes to the documentation (not applicable)
• I have assigned this pull request to a milestone (for repository code-owners and collaborators only)

This pull request was created by Codex.

[thepastaclaw]

🕓 Ready for review — 12 ahead in queue (commit 956e1e0)
Queue position: 13/13

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 01d7ac8d-f288-4c72-9f08-bd4222c6a79a

📥 Commits

Reviewing files that changed from the base of the PR and between b3e5295 and 46dfad3.

📒 Files selected for processing (3)

• src/wallet/test/wallet_tests.cpp
• src/wallet/wallet.cpp
• src/wallet/wallet.h

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Walkthrough

CWallet::IsLocked now acquires cs_wallet before checking mixing-only access. CWallet::Lock performs key cleansing and updates fOnlyMixingAllowed within the same lock scope. The wallet state declaration now marks fOnlyMixingAllowed as guarded by cs_wallet. A concurrency test verifies blocking and mixing-only lock behavior.

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

Mergeability Score: ⚪ Minimal · up to 46dfa

The change serializes wallet mixing-only lock state reads and transitions and adds focused concurrency coverage; no actionable merge-blocking risk remains after normal checks.

Possibly related PRs

• dashpay/dash#7600: Modifies the same wallet locking methods and mixing-only state.

Suggested reviewers: knst

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
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.
Title check	✅ Passed	The title clearly and concisely describes the main change: synchronizing the wallet’s mixing-only lock state.
Description check	✅ Passed	The description directly explains the synchronization issue, the implemented mutex changes, and the related regression test.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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

[chatgpt-codex-connector]

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