Bugfix FXIOS-31023 [Logins] Fix crash when multiple addLogin calls race across threads

[Aniket-pd]

:scroll: Tickets

Jira ticket Github issue

:bulb: Description

Wraps storage/FFI calls in RustLogins with dispatch to the serial queue after getStoredKey to prevent race conditions. Adds a concurrent test to verify multiple logins can be added safely.

:pencil: Checklist

• [x] I filled in the ticket numbers and a description of my work
• [x] I updated the PR name to follow our PR naming guidelines
• [x] I ensured unit tests pass and wrote tests for new code
• [ ] If working on UI, I checked and implemented accessibility (Dynamic Text and VoiceOver)
• [ ] If adding telemetry, I read the data stewardship requirements and will request a data review
• [ ] If adding or modifying strings, I read the guidelines and will request a string review from l10n
• [ ] If needed, I updated documentation and added comments to complex code

[mobiletest-ci-bot]

	Messages
:book:	Project coverage: 37.66%

💪 Quality guardian

1 tests files modified. You're a champion of test coverage! 🚀

🧹 Tidy commit

Just 2 file(s) touched. Thanks for keeping it clean and review-friendly!

✅ Per-file coverage

All changed files meet the threshold of 35.0%.

libStorage.a: Coverage: 54.52

File	Coverage
RustLogins.swift	37.48%	⚠️

Generated by :no_entry_sign: Danger Swift against 5f2a5f7328949d8a776aec598b2a25f640598798

[mergify[bot]]

This pull request has conflicts when rebasing. Could you fix it @Aniket-pd? 🙏

[Aniket-pd]

Nice work @Aniket-pd, thanks for taking this ticket on!

It makes more sense to jump back to the queue for the work in the completion blocks.

One issue I noticed. When I ran the full test suite (or even the full test class) locally, your test passed just fine. Now, as I was about to try running it repeatedly, I noticed it crashes when I run even just once individually. Are you able to see this crash as well? 🤔

Yes, I’m able to reproduce the crash locally as well when running the test individually I’ll investigate the cause

[ih-codes]

Hi @Aniket-pd , looks like we have some compiler errors building the unit test suite. Could something maybe have gotten changed after the merge conflicts were addressed?

❌  /Users/[REDACTED]/git/firefox-ios/Storage/Rust/RustLogins.swift:227:20: type 'RustLogins' does not conform to protocol 'LoginsProtocol'

public final class RustLogins: LoginsProtocol, KeyManager, @unchecked Sendable {
                   ^