fix: AOT interop with managed .NET runtimes

[jpnurmi]

📜 Description

Prevent the Cocoa SDK from capturing managed .NET exceptions.

First of all, we need to avoid overriding Mono's Mach exception port for EXC_BAD_ACCESS and EXC_ARITHMETIC to allow handling the respective Unix signals. Secondly, Sentry's signal handler has to first invoke Mono's signal handler to give it a chance to convert it into a managed exception and redirect execution into the managed runtime’s exception handling machinery, so that managed code can catch and process the exception as if it were a normal .NET exception. Finally, Sentry's crash capturing kicks in only if we do not detect instruction or stack pointer modifications in the context.

💡 Motivation and Context

Fixes a long-standing issue with redundant crash events with Sentry.NET on iOS:

• Prevent Native/Cocoa SDKs from capturing errors that also get captured by .NET sentry-dotnet#3954

See also similar Sentry Native changes for Android:

• fix: AOT interop with managed .NET runtimes sentry-native#1392

💚 How did you test it?

1. With the newly developed Sentry .NET integration test for iOS:
   • iOS & Android integration tests sentry-dotnet#4559
2. Manually with Sentry.Samples.Maui in Sentry.NET:
   • WIP: Prevent Cocoa SDK from capturing errors that also get captured by .NET sentry-dotnet#4537

📝 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.

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.070%. Comparing base (1655116) to head (be528ee).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...ash/Recording/Monitors/SentryCrashMonitor_Signal.c	0.000%	24 Missing ⚠️
...ording/Monitors/SentryCrashMonitor_MachException.c	25.000%	3 Missing ⚠️
Sources/Sentry/PrivateSentrySDKOnly.m	50.000%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #6193       +/-   ##
=============================================
- Coverage   85.169%   85.070%   -0.100%     
=============================================
  Files          452       452               
  Lines        27659     27696       +37     
  Branches     12117     12128       +11     
=============================================
+ Hits         23557     23561        +4     
- Misses        4054      4091       +37     
+ Partials        48        44        -4     

Files with missing lines	Coverage Δ
Sources/Sentry/SentryCrashIntegration.m	100.000% <100.000%> (ø)
...entryCrash/Recording/Monitors/SentryCrashMonitor.c	80.952% <100.000%> (+0.624%)	⬆️
...SentryCrash/Recording/Tools/SentryCrashCPU_arm64.c	100.000% <100.000%> (ø)
Sources/Sentry/PrivateSentrySDKOnly.m	81.818% <50.000%> (-0.535%)	⬇️
...ording/Monitors/SentryCrashMonitor_MachException.c	35.123% <25.000%> (-0.171%)	⬇️
...ash/Recording/Monitors/SentryCrashMonitor_Signal.c	49.253% <0.000%> (-9.675%)	⬇️

... and 6 files with indirect coverage changes

---

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1216.42 ms	1251.93 ms	35.52 ms
Size	23.75 KiB	1.00 MiB	1000.37 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
4a7a005	1229.15 ms	1243.35 ms	14.20 ms
ae7be93	1236.24 ms	1258.18 ms	21.94 ms
b9ceffb	1222.57 ms	1247.96 ms	25.39 ms
884b224	1221.11 ms	1255.88 ms	34.77 ms
2a9a505	1221.49 ms	1238.49 ms	17.00 ms
00d9740	1223.53 ms	1249.75 ms	26.22 ms
e8f9a1d	1229.02 ms	1264.17 ms	35.15 ms
6502818	1229.08 ms	1245.46 ms	16.37 ms
5712478	1220.10 ms	1239.69 ms	19.59 ms
8da82b4	1220.08 ms	1248.24 ms	28.16 ms

App size

Revision	Plain	With Sentry	Diff
4a7a005	23.75 KiB	979.96 KiB	956.22 KiB
ae7be93	23.75 KiB	879.24 KiB	855.49 KiB
b9ceffb	23.75 KiB	969.07 KiB	945.32 KiB
884b224	23.75 KiB	879.55 KiB	855.80 KiB
2a9a505	23.75 KiB	874.46 KiB	850.71 KiB
00d9740	23.75 KiB	938.32 KiB	914.57 KiB
e8f9a1d	23.75 KiB	969.78 KiB	946.04 KiB
6502818	23.75 KiB	959.45 KiB	935.70 KiB
5712478	23.75 KiB	969.28 KiB	945.54 KiB
8da82b4	23.75 KiB	913.63 KiB	889.88 KiB

Previous results on branch: jpnurmi/mono-interop

Startup times

Revision	Plain	With Sentry	Diff
f651762	1232.57 ms	1259.68 ms	27.11 ms
d171c8f	1226.86 ms	1256.95 ms	30.09 ms
1666de5	1208.65 ms	1245.50 ms	36.85 ms

App size

Revision	Plain	With Sentry	Diff
f651762	23.75 KiB	975.29 KiB	951.55 KiB
d171c8f	23.75 KiB	1.02 MiB	1016.31 KiB
1666de5	23.75 KiB	1.01 MiB	1016.19 KiB

[jpnurmi]

Screen.Recording.2025-09-18.at.11.54.52.mov