[WIP] fix: interop with managed Mono/CoreCLR runtimes

[jpnurmi]

📜 Description

WIP: Prevent the Cocoa SDK from capturing managed .NET exceptions.

First, if a managed Mono/CoreCLR runtime is detected based on previously installed Mach exception ports, we avoid overriding the port to let the managed runtime keep its null exception port for EXC_BAD_ACCESS and EXC_ARITHMETIC.

Secondly, when running within a managed runtime, Cocoa SDK's signal handler invokes the previously installed signal handlers to give the managed runtime first 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.

💡 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

💚 How did you test it?

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

📝 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 55.00000% with 36 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.606%. Comparing base (e70670c) to head (ed98b04).
⚠️ Report is 3 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...ash/Recording/Monitors/SentryCrashMonitor_Signal.c	3.030%	32 Missing ⚠️
...ording/Monitors/SentryCrashMonitor_MachException.c	76.470%	4 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #6193       +/-   ##
=============================================
- Coverage   86.697%   86.606%   -0.092%     
=============================================
  Files          436       436               
  Lines        37076     37151       +75     
  Branches     17390     17420       +30     
=============================================
+ Hits         32144     32175       +31     
- Misses        4890      4931       +41     
- Partials        42        45        +3     

Files with missing lines	Coverage Δ
...SentryCrash/Recording/Tools/SentryCrashCPU_arm64.c	100.000% <100.000%> (ø)
...entryCrash/Recording/Tools/SentryCrashCPU_x86_64.c	100.000% <100.000%> (ø)
...ording/Monitors/SentryCrashMonitor_MachException.c	41.747% <76.470%> (+2.021%)	⬆️
...ash/Recording/Monitors/SentryCrashMonitor_Signal.c	55.681% <3.030%> (-11.215%)	⬇️

... and 8 files with indirect coverage changes

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1232.57 ms	1259.68 ms	27.11 ms
Size	23.75 KiB	975.29 KiB	951.55 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
7c7ac56	1225.90 ms	1250.22 ms	24.33 ms
8ea5293	1242.70 ms	1262.25 ms	19.55 ms
35c962f	1207.61 ms	1235.90 ms	28.29 ms
aa98fe8	1227.69 ms	1253.18 ms	25.50 ms
339539a	1219.58 ms	1254.63 ms	35.05 ms
0ac4c65	1236.85 ms	1267.84 ms	30.98 ms
6ee4973	1228.42 ms	1252.26 ms	23.84 ms
b13e93a	1236.24 ms	1247.33 ms	11.08 ms
2e79f5f	1220.53 ms	1249.35 ms	28.82 ms
5ae9ff1	1222.31 ms	1250.96 ms	28.65 ms

App size

Revision	Plain	With Sentry	Diff
7c7ac56	23.75 KiB	902.49 KiB	878.74 KiB
8ea5293	23.75 KiB	852.24 KiB	828.49 KiB
35c962f	23.75 KiB	854.77 KiB	831.02 KiB
aa98fe8	23.75 KiB	891.01 KiB	867.26 KiB
339539a	23.75 KiB	968.24 KiB	944.50 KiB
0ac4c65	23.75 KiB	968.24 KiB	944.50 KiB
6ee4973	23.75 KiB	896.53 KiB	872.79 KiB
b13e93a	23.75 KiB	855.37 KiB	831.62 KiB
2e79f5f	23.75 KiB	928.87 KiB	905.12 KiB
5ae9ff1	23.74 KiB	971.82 KiB	948.08 KiB

[jpnurmi]

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