fix: Add persistence for context to fix watchdog termination events

[philprime]

📜 Description

• Adds file persistence of the scope context to serialize for watchdog termination events

• Changes the watchdog termination scope observer as a collective entry point forwarding events to multiple processors to segment the logic into individual, testable components

• Refactors the existing breadcrumb persistence logic into a SentryWatchdogTerminationBreadcrumbProcessor. The implementation is not changed in this PR but prepared for future refactoring. A lot of the file operations are split with the SentryFileManager and would require more work.

• Adds a SentryWatchdogTerminationContextProcessor to process and persist the context to the file system. It uses the newly introduced `Sentry

• To not add even more logic to the SentryFileManager I added a wrapper store SentryScopeContextPersistentStore which handles encoding/decoding and file operations using the file manager.

• The SentryWatchdogTerminationContextProcessor is dispatching the saving via the persistent store on a background thread to reduce the impact on the main thread.

• The dispatch queue wrapper is created by the SentryDispatchFactory

In general I tried to bring a more constructor-based dependency injection style architecture into this PR, to make them replaceable and testable as individual units.

Originally the logic of SentryScopeContextPersistentStore was in the SentryWatchdogTerminationContextProcessor, therefore it's functionality is now slim and we could consider moving the method directly to the SentryWatchdogTerminationScopeObserver, but that would then. not match with the breadcrumb processor.

I believe the additional file is fine for now and can be refactored again at a future point.

💡 Motivation and Context

Closes #5182

💚 How did you test it?

📝 Checklist

You have to check all boxes before merging:

• 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.

Blocked by

• test: Add test target for SentryTestUtils with additional mock testing #5303
• fix: Add nullability to deserialization method #5313

[codecov]

Codecov Report

Attention: Patch coverage is 99.31973% with 9 lines in your changes missing coverage. Please review.

Project coverage is 92.996%. Comparing base (864caac) to head (ee02a86).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...tence/SentryScopeContextPersistentStoreTests.swift	98.009%	4 Missing ⚠️
...stence/TestSentryScopeContextPersistentStore.swift	60.000%	4 Missing ⚠️
Sources/Sentry/SentryDependencyContainer.m	96.428%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #5242       +/-   ##
=============================================
+ Coverage   92.805%   92.996%   +0.190%     
=============================================
  Files          691       702       +11     
  Lines        86693     87809     +1116     
  Branches     30112     31512     +1400     
=============================================
+ Hits         80456     81659     +1203     
+ Misses        6140      6050       -90     
- Partials        97       100        +3     

Files with missing lines	Coverage Δ
...ors/SentryWatchdogTerminationBreadcrumbProcessor.m	100.000% <100.000%> (ø)
Sources/Sentry/SentryFileManager.m	94.744% <100.000%> (+0.307%)	⬆️
Sources/Sentry/SentrySDK.m	88.800% <100.000%> (+0.060%)	⬆️
...es/Sentry/SentryWatchdogTerminationScopeObserver.m	55.555% <100.000%> (-19.170%)	⬇️
Sources/Sentry/SentryWatchdogTerminationTracker.m	100.000% <100.000%> (ø)
...try/SentryWatchdogTerminationTrackingIntegration.m	84.285% <100.000%> (-0.090%)	⬇️
...rs/SentryWatchdogTerminationContextProcessor.swift	100.000% <100.000%> (ø)
...ersistence/SentryScopeContextPersistentStore.swift	100.000% <100.000%> (ø)
...yTests/Helper/SentryDependencyContainerTests.swift	100.000% <100.000%> (ø)
...ts/SentryTests/Helper/SentryFileManagerTests.swift	97.083% <100.000%> (+0.035%)	⬆️
... and 13 more

... and 25 files with indirect coverage changes

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1224.10 ms	1245.00 ms	20.90 ms
Size	23.76 KiB	835.19 KiB	811.43 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
676fe22	1220.71 ms	1240.14 ms	19.43 ms
06bc323	1223.12 ms	1252.88 ms	29.76 ms
9158639	1216.86 ms	1236.89 ms	20.03 ms
b9a9dca	1196.09 ms	1225.14 ms	29.05 ms
2334b81	1246.76 ms	1254.48 ms	7.72 ms
a716092	1234.94 ms	1255.18 ms	20.24 ms
f1c36e0	1210.96 ms	1228.22 ms	17.27 ms
2124551	1246.10 ms	1254.84 ms	8.74 ms
0ecf042	1228.25 ms	1250.67 ms	22.42 ms
9f0d9e0	1226.31 ms	1242.70 ms	16.40 ms

App size

Revision	Plain	With Sentry	Diff
676fe22	21.58 KiB	698.12 KiB	676.54 KiB
06bc323	22.30 KiB	832.29 KiB	809.99 KiB
9158639	22.31 KiB	821.12 KiB	798.81 KiB
b9a9dca	21.58 KiB	414.59 KiB	393.01 KiB
2334b81	23.76 KiB	821.44 KiB	797.68 KiB
a716092	21.58 KiB	424.34 KiB	402.76 KiB
f1c36e0	21.58 KiB	670.39 KiB	648.81 KiB
2124551	22.85 KiB	411.69 KiB	388.84 KiB
0ecf042	21.58 KiB	631.82 KiB	610.24 KiB
9f0d9e0	21.58 KiB	424.28 KiB	402.70 KiB

Previous results on branch: philprime/issue-5182

Startup times

Revision	Plain	With Sentry	Diff
c5b273a	1212.13 ms	1235.94 ms	23.81 ms
c34e9ed	1223.86 ms	1249.84 ms	25.98 ms
bcd1b71	1217.71 ms	1229.96 ms	12.25 ms
c9efa02	1229.42 ms	1251.57 ms	22.16 ms
69ce027	1232.45 ms	1251.65 ms	19.21 ms
9b69890	1244.68 ms	1258.16 ms	13.48 ms
8c53c21	1223.46 ms	1246.42 ms	22.96 ms
496853a	1225.18 ms	1244.33 ms	19.15 ms
35d6c88	1229.02 ms	1254.54 ms	25.52 ms
a24ff85	1209.27 ms	1239.76 ms	30.48 ms

App size

Revision	Plain	With Sentry	Diff
c5b273a	23.76 KiB	829.41 KiB	805.65 KiB
c34e9ed	23.76 KiB	829.34 KiB	805.59 KiB
bcd1b71	23.76 KiB	829.42 KiB	805.66 KiB
c9efa02	23.76 KiB	829.31 KiB	805.55 KiB
69ce027	23.76 KiB	829.42 KiB	805.66 KiB
9b69890	23.76 KiB	874.87 KiB	851.11 KiB
8c53c21	23.76 KiB	829.42 KiB	805.66 KiB
496853a	23.76 KiB	830.09 KiB	806.33 KiB
35d6c88	23.76 KiB	821.23 KiB	797.47 KiB
a24ff85	23.76 KiB	830.18 KiB	806.42 KiB

[philprime]

This PR grew quite in size. I am now going to extract smaller PRs for necessary changes than can be seen as isolated changes (i.e. fixing compiler flags or serialization).

[metcalfealex]

👋 Any idea when this fix might get merged? We are very interested in it 😄 as its blocking us from upgrading Sentry from 8.43.0 to the latest version (we are using Sentry RN and would like to upgrade to pick up the Xcode 16.3 fixes)

[philprime]

Hi @metcalfealex I believe the PR is ready for review now. As soon as my colleagues get a chance to review it, we'll make sure to merge it soon. This issue has the highest priority right now, but grew larger in size than expected.

[github-actions]

🚨 Detected changes in high risk code 🚨

High-risk code can easily blow up and is hard to test. We had severe bugs in the past. Be extra careful when changing these files, and have an extra careful look at these:

• Sources/Sentry/SentryFileManager.m

[philprime]

I had to do this because. SENTRY_TEST || SENTRY_TEST_CI alone did not work for macOS and defined(SENTRY_TEST) || defined(SENTRY_TEST_CI) did not work for iOS.