🐛 FileHandler actor's append(line:) method crashes on some devices #5667
Description
Describe the bug
I am getting rare crashes from some users. The problem starts with PaywallEventsManager.track(featureEvent:) which seems to call PaywallEventStore.store(_:) and that calls FileHandler.append(line:). Perhaps due to insufficient space or some other problem, this method crashes at line 81 on self.fileHandle.write(line.asData)
The issue can happen both in background or while the app is open. I see crashes from iOS 15 and 18, so perhaps it affects all iOS versions.
Platform
iOS
SDK version
RevenueCat 5.44.0
SDK integration method
Swift Package Manager
StoreKit version
StoreKit 2 (default on versions >=5.0.0)
OS version
iOS 15-18
Xcode version
26.0
Device and/or simulator
Device
Environment
Production
How widespread is the issue
Rare, perhaps 1%
Debug logs
Last Exception Backtrace:
0 CoreFoundation 0x18f2880c0 __exceptionPreprocess + 164 (NSException.m:249)
1 libobjc.A.dylib 0x18c721abc objc_exception_throw + 88 (objc-exception.mm:356)
2 Foundation 0x18e07054c _NSFileHandleRaiseOperationExceptionWhileReading + 272 (NSFileHandle.m:72)
3 Foundation 0x18de6a8ac -[NSConcreteFileHandle writeData:] + 300 (NSFileHandle.m:905)
4 MyApp 0x101233f28 FileHandler.append(line:) + 20 (FileHandler.swift:81)
5 MyApp 0x101233f28 protocol witness for FileHandlerType.append(line:) in conformance FileHandler + 20 (/<compiler-generated>:77)
6 MyApp 0x101233f28 PaywallEventStore.store(_:) + 144 (PaywallEventStore.swift:50)
7 MyApp 0x1012b23ad specialized PaywallEventsManager.track(featureEvent:) + 1 (PaywallEventsManager.swift:50)
8 MyApp 0x1012a12a1 <deduplicated_symbol> + 1
9 MyApp 0x100dce341 <deduplicated_symbol> + 1
10 MyApp 0x100eff831 <deduplicated_symbol> + 1
11 MyApp 0x100dce6bd <deduplicated_symbol> + 1
12 MyApp 0x100e3c591 specialized thunk for @escaping @isolated(any) @callee_guaranteed @async () -> (@out A) + 1
13 MyApp 0x100dce6bd <deduplicated_symbol> + 1
14 libswift_Concurrency.dylib 0x19abd1241 completeTaskWithClosure(swift::AsyncContext*, swift::SwiftError*) + 1 (Task.cpp:537)Steps to reproduce
I myself cannot reproduce the problem.