RUM-7543 Allocate rwlock on the heap

[maxep]

What and why?

Given this exemple:

var rwlock = pthread_rwlock_t()
pthread_rwlock_rdlock(&rwlock)

rwlock is not a real pointer that is long-lasting valid. Instead the lock pointer should be allocated on the heap.

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)
• Make sure each commit and the PR mention the Issue number or JIRA reference
• Add CHANGELOG entry for user facing changes
• Add Objective-C interface for public APIs (see our guidelines (internal) and run make api-surface)

[datadog-datadog-prod-us1]

Datadog Report

Branch report: maxep/RUM-7543/rwlock-heap-allocation
Commit report: bd1e60e
Test service: dd-sdk-ios

✅ 0 Failed, 51 Passed, 3847 Skipped, 2m 0.35s Total duration (2m 32.45s time saved)

[mariedm]

Nice find! Thanks for this fix. 🛠️ I wonder how often this lead to unexpected crashes given that we use this lock in many parts of the SDK.

[maxep]

@mariedm I don't expect it to be much of a problem in its current state since the lock is wrapped within a class, but still it was at risk.

[simaoseica-dd]

Can you add more tests to the ReadWriteLockTests? For instance, tests that trigger the ReadWriteLock deinit concurrently?

[maxep]

@simaoseica-dd, the ReadWriteLock is now 100% covered 👍

[simaoseica-dd]

LGTM

[maxep]

/merge

[dd-devflow]

View all feedbacks in Devflow UI.

2025-05-20 11:49:37 UTC ℹ️ Start processing command /merge

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2025-05-20 11:49:42 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in develop is approximately 1h (p90).

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2025-05-20 12:34:25 UTC ℹ️ MergeQueue: This merge request was merged