PR Stack (Callback Errors)

• fix(core): Handle callback errors #6140
• fix(core): [Callback Errors 1] Report callback failures #6141
• ref(core): [Callback Errors 2] Mark SDK-owned event processors #6162
• fix(core): [Callback Errors 3] Drop failed processor data #6142
• fix(core): [Callback Errors 4] Drop failed breadcrumbs #6143
• fix(core): [Callback Errors 5] Handle tracesSampler failures #6163
• fix(core): [Callback Errors 6] Handle profilesSampler failures #6164
• fix(core): [Callback Errors 7] Handle replay sampling failures #6165
• fix(core): [Callback Errors 8] Report dropped profiles #6166
• fix(integrations): [Callback Errors 9] Guard custom callbacks #6167
• feat(callbacks): [Callback Errors 10] Add opt-in strict callback mode #6173

📜 Description

Disable profiling when profilesSampler throws, without changing trace sampling. Skip the configured profilesSampleRate and do not inherit a parent's profiling decision after callback failure.

The parent path preserves the trace sampling decision, trace sample rate, and sample-random value, including backfilling when needed. It does not mutate the original parent decision. A callback deliberately returning null still uses the existing fallback behavior. Error logging and catch types are unchanged.

If tracesSampler also throws, the failure behavior from #6163 disables both tracing and profiling regardless of the parent's decision. Its immediate callback_error reports and accepted duplicate sampling-loss reports remain unchanged.

💡 Motivation and Context

A failed profiling callback must not enable profiling through a static rate or parent inheritance. Returning the parent's entire sampling decision would bypass the local failure result and could re-enable profiling, so the failure path retains only the parent's trace fields.

• refs: Align callback error handling with other SDKs #6081
• Spec discussion: docs(sdk): Specify callback error isolation for user callbacks sentry-docs#19189

💚 How did you test it?

• ./gradlew spotlessApply apiDump
• Original focused validation passed 395 tests; all four original regression tests failed before the production fix and passed afterward.
• After merging the updated fix(core): [Callback Errors 5] Handle tracesSampler failures #6163, reran TracesSamplerTest, ScopesTest, OpenTelemetry SentrySamplerTest, and the core API check successfully.
• Covered absent/zero/full static profile rates with zero sample-random value, a working trace sampler after profiling failure, sampled and unsampled parents, and both samplers failing despite a sampled parent.
• Updated existing null-result tests to invoke callbacks actually returning null.
• After merge-forward through fix(integrations): [Callback Errors 9] Guard custom callbacks #6167, 3,814 core/OpenTelemetry tests passed, along with formatting and API checks.

📝 Checklist

• I added GH Issue ID & Linear ID
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.
• Public API changes reviewed by another Mobile SDK team member or implemented according to the develop docs spec.

🔮 Next steps

Profile discard accounting is handled separately in #6166. Profile/replay artifact cleanup remains a follow-up. The broader callback-boundary catch-type changes remain deferred to the next major.

⚠️ Merge this PR using a merge commit (not squash). Only the collection branch is squash-merged into main.