ICU causes crash, when running on Mac (.NET8)

[i-nikityuk]

Description

Firebase.Crashlytics library requires "_ExportSymbolsExplicitly" set to "false" for net8.0-ios TFMs to avoid issues with crash reporting.
see here

However installing IPA on Mac silicon with such key causing ICU crash.
Removing "_ExportSymbolsExplicitly" at build time is impossible as I can't predict if app will be run on iOS or Mac or both.

Thread 10 Crashed:: Dispatch queue: com.google.fira.worker
0 libsystem_kernel.dylib 0x182709388 __pthread_kill + 8
1 libsystem_pthread.dylib 0x18274288c pthread_kill + 296
2 libsystem_c.dylib 0x18264bc60 abort + 124
3 Firebase.Test.iOS 0x100d99000 sigabrt_signal_handler.cold.1 + 48 (mini-posix.c:248)
4 Firebase.Test.iOS 0x100d5c824 sigabrt_signal_handler + 196 (mini-posix.c:246)
5 Firebase.Test.iOS 0x100495164 FIRCLSSignalSafeInstallPreexistingHandlers + 244
6 Firebase.Test.iOS 0x100494f28 FIRCLSSignalHandler + 564
7 libsystem_platform.dylib 0x18277c624 _sigtramp + 56
8 libsystem_pthread.dylib 0x18274288c pthread_kill + 296
9 libsystem_c.dylib 0x18264bc60 abort + 124
10 libsystem_malloc.dylib 0x182550174 malloc_vreport + 892
11 libsystem_malloc.dylib 0x182553c90 malloc_report + 64
12 libsystem_malloc.dylib 0x18255821c ___BUG_IN_CLIENT_OF_LIBMALLOC_POINTER_BEING_FREED_WAS_NOT_ALLOCATED + 32
13 libicucore.A.dylib 0x185f9dad8 icu::Locale::setToBogus() + 52
14 libicucore.A.dylib 0x185f9de40 icu::Locale::operator=(icu::Locale const&) + 40
15 libicucore.A.dylib 0x186109800 icu::number::LocalizedNumberFormatter::LocalizedNumberFormatter(icu::number::impl::MacroProps&&, icu::Locale const&) + 212
16 libicucore.A.dylib 0x1860a8390 icu::DecimalFormat::touch(UErrorCode&) + 240
17 libicucore.A.dylib 0x1860a8d78 icu::DecimalFormat::DecimalFormat(icu::UnicodeString const&, icu::DecimalFormatSymbols*, UNumberFormatStyle, UErrorCode&) + 424
18 libicucore.A.dylib 0x18612710c icu::NumberFormat::makeInstance(icu::Locale const&, UNumberFormatStyle, signed char, UErrorCode&) + 1668
19 libicucore.A.dylib 0x1861268c0 icu::LocaleCacheKeyicu::SharedNumberFormat::createObject(void const*, UErrorCode&) const + 88
20 libicucore.A.dylib 0x186029948 icu::UnifiedCache::_get(icu::CacheKeyBase const&, icu::SharedObject const*&, void const*, UErrorCode&) const + 168
21 libicucore.A.dylib 0x186072bd0 0x185f7e000 + 1002448
22 libicucore.A.dylib 0x186126a28 0x185f7e000 + 1739304
23 libicucore.A.dylib 0x1861262f0 icu::NumberFormat::createInstance(icu::Locale const&, UNumberFormatStyle, UErrorCode&) + 64
24 libicucore.A.dylib 0x1861b9d64 unum_open + 360
25 CoreFoundation 0x1828574e0 __cficu_unum_open + 64
26 CoreFoundation 0x1828570a0 CFNumberFormatterCreate + 276
27 Foundation 0x183e1b568 -[NSNumberFormatter _regenerateFormatter] + 232
28 Foundation 0x183e767ac -[NSNumberFormatter decimalSeparator] + 292
29 Foundation 0x183e295ec getObjectValue + 436
30 Foundation 0x183e76378 -[NSNumberFormatter getObjectValue:forString:errorDescription:] + 312
31 Foundation 0x183e6086c -[NSNumberFormatter numberFromString:] + 56
32 Firebase.Test.iOS 0x100439208 -[APMRemoteConfig numberFromString:] + 68
33 Firebase.Test.iOS 0x100439460 -[APMRemoteConfig numberFromCacheWithKey:defaultValue:maxValue:minValue:block:] + 304
34 Firebase.Test.iOS 0x10043975c -[APMRemoteConfig intValueFromCacheWithKey:defaultValue:maxValue:minValue:] + 160
35 Firebase.Test.iOS 0x1003c1b10 +[APMDataTypeValidator isValidPublicEventParameterValue:failureCode:] + 68
36 Firebase.Test.iOS 0x1003cfaa0 APMNormalizedParametersForParametersAndEventName + 476
37 Firebase.Test.iOS 0x1003cbd38 -[APMEvent initWithOrigin:isPublic:name:timestamp:previousTimestamp:parameters:] + 360
38 Firebase.Test.iOS 0x1003e3294 -[APMMeasurement logEventOnWorkerQueueWithOrigin:isPublicEvent:name:parameters:timestamp:enabled:ignoreEnabled:ignoreInterceptor:interceptor:addedScreenParameters:] + 224
39 Firebase.Test.iOS 0x1003e3154 __151-[APMMeasurement logEventWithOrigin:isPublicEvent:name:parameters:timestamp:enabled:ignoreEnabled:ignoreInterceptor:interceptor:addedScreenParameters:]_block_invoke + 60
40 Firebase.Test.iOS 0x100439d34 __51-[APMScheduler scheduleOnWorkerQueueBlockID:block:]_block_invoke + 44
41 libdispatch.dylib 0x18258ab2c _dispatch_call_block_and_release + 32
42 libdispatch.dylib 0x1825a485c _dispatch_client_callout + 16
43 libdispatch.dylib 0x182593350 _dispatch_lane_serial_drain + 740
44 libdispatch.dylib 0x182593e2c _dispatch_lane_invoke + 388
45 libdispatch.dylib 0x18259e264 _dispatch_root_queue_drain_deferred_wlh + 292
46 libdispatch.dylib 0x18259dae8 _dispatch_workloop_worker_thread + 540
47 libsystem_pthread.dylib 0x18273ee64 _pthread_wqthread + 292
48 libsystem_pthread.dylib 0x18273db74 start_wqthread + 8

Reproduction Steps

Minimal project zip file is around 35MB as it is using non-public binding libraries for Firebase. I couldn't attach it here (seems too big). Let me know if you need a sample project and where I can send it to.

Steps to replicate:

1. Update "GoogleService-Info.plist" file
2. Update "Bundle identifier" in Info.plist
3. Build test project: (dotnet publish Firebase.Test.iOS.csproj -f net8.0-ios -c Release -p:ArchiveOnBuild=true -p:RuntimeIdentifier=ios-arm64)
4. Install IPA on Mac
5. BOOM

full_crash_report.txt

Expected behavior

No crash

Actual behavior

Crash

Regression?

"_ExportSymbolsExplicitly" is a workaround for NET8 builds, NET7 works fine

Known Workarounds

1. Build using net9.0-ios TFM (.NET 9.0.300 works for me)
2. Remove "_ExportSymbolsExplicitly(false)" from project file (Crash reporting will stop working)

Configuration

.NET SDK:
Version: 9.0.300
Commit: 15606fe0a8
Workload version: 9.0.300-manifests.87b8cca8
MSBuild version: 17.14.5+edd3bbf37

Runtime Environment:
OS Name: Mac OS X
OS Version: 15.5
OS Platform: Darwin
RID: osx-arm64
Base Path: /usr/local/share/dotnet/sdk/9.0.300/

.NET workloads installed:
[ios]
Installation Source: SDK 9.0.300
Manifest Version: 18.4.9289/9.0.100
Manifest Path: /usr/local/share/dotnet/sdk-manifests/9.0.100/microsoft.net.sdk.ios/18.4.9289/WorkloadManifest.json
Install Type: FileBased

[maccatalyst]
Installation Source: SDK 9.0.300
Manifest Version: 18.4.9289/9.0.100
Manifest Path: /usr/local/share/dotnet/sdk-manifests/9.0.100/microsoft.net.sdk.maccatalyst/18.4.9289/WorkloadManifest.json
Install Type: FileBased

[android]
Installation Source: SDK 9.0.300
Manifest Version: 35.0.61/9.0.100
Manifest Path: /usr/local/share/dotnet/sdk-manifests/9.0.100/microsoft.net.sdk.android/35.0.61/WorkloadManifest.json
Install Type: FileBased

Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.5
Architecture: arm64
Commit: e36e4d1

.NET SDKs installed:
8.0.409 [/usr/local/share/dotnet/sdk]
9.0.300 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 8.0.16 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 8.0.16 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
x64 [/usr/local/share/dotnet/x64]
registered at [/etc/dotnet/install_location_x64]

Environment variables:
Not set

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

Other information

No response

[filipnavara]

This was an issue that was previously fixed in various configurations. It was caused by a conflict between the system ICU libraries and the ones bundled with .NET application. As you found, this is already fixed in .NET 9.

.NET 8 iOS is out of support since May 14, 2025 (https://dotnet.microsoft.com/en-us/platform/support/policy/maui) so this is unlikely to get any fixes.

[dotnet-policy-service]

Tagging subscribers to 'os-ios': @vitek-karas, @kotlarmilos, @ivanpovazan, @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-globalization
See info in area-owners.md if you want to be subscribed.

[vitek-karas]

I agree with Filip on this one. .NET 8 is out of support, so we would have a hard time even shipping the fix. Additionally, this seems to have a workaround, which is not ideal, but makes it possible. And .NET 9+ doesn't have this problem.

Thank you for reporting the issue, but we're not going to consider this for servicing. If you have more information, feel free to reopen or open a new issue.

[i-nikityuk]

Thank you for your responses @filipnavara @vitek-karas I have completely forgot about separate support terms for MAUI and was relying on .NET support terms, my mistake. Feel free to close.